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2014 BIOT Expedition Blog Jump to project background

  • BIOT Science Expedition 2014 contribution to Chagos Science Resource Portal - Dr Elizabeth Widman

    Chagos Science Resource Portal

    Dr Elizabeth Widman, University of Warwick

    I am leading on the ambitious ‘Chagos Science Resource Portal’ project which is, among other things, aiming to develop an online relational database summarising all Chagos scientific output (Figure 28). The resource portal developed out of earlier BIOT Science Advisory Group (SAG) requests for expedition logs and the project was approved by the SAG and BIOT Administration two years ago. The CCT is providing some limited funding for the portal at present which will enable the development of the site architecture. 

    The expedition has greatly added to the development of the resource portal by giving me a first-hand understanding of Chagos as a whole as well as the research being undertaken there. Having had the opportunity to do 27 dives, 63 sea-cucumber transects, countless hours snorkelling around the boats, assisting directly in both bird work (capturing and banding sooty tern chicks and also doing estimates for egg density) and with crab counts on Eagle Island has given me a better understanding of the data-sets I will be incorporating into the resource portal and also the needs of the scientists that will be accessing it.

    As part of the Pacific Marlin seminar series I presented the ‘Chagos Resource Portal’ as a concept to the 2014 expedition team. This created a platform for discussions on how to best incorporate existing and future datasets.

    A major initiative of the 2014 science expedition was to consolidate and identify key longterm monitoring sites and document these using GPS points, detailed site descriptions and photography. These sites, and the data associated with them, will be a key part of the ‘Chagos Resource Portal’.

     

    Figure 28: Overview of Chagos Science Resource Portal

     

  • Pete Carr BIOT Science Expedition 2014 Initial Report Terrestrial Invasive Species

    Monitoring the Spread of Terrestrial Invasive Species

    Peter Carr, Permian Global

    From a terrestrial perspective, along with the decline of certain breeding seabirds, the spread of invasive species throughout the Chagos Archipelago is of gravest concern and requires urgent practical conservation management and scientific base-lining.  Invasive species in the Chagos that require management now include native as well as introduced species.  The species of main concern are native Coconut Cocus nucifera where it has been planted as a crop in areas that were cleared of native forest and where it is detrimentally encroaching on other habitats, e.g. mangroves; native Hawaiian Dodder Cassytha filiformis where it is growing over and destroying Sooty Tern fairs (breeding sites); introduced Rat-tail Stachytarpheta sp. where it is growing over and rendering useless Sooty Tern fairs; Native Mulberry Pipturus argenteus where it is encroaching on other habitat, especially on the Bois Mangues where it is choking out new growth Pisonia grandis; introduced White Trumpet Tree Tabebuia pallida where it is choking out other species, especially on North Brother and Diego Garcia and, introduced Longhorn Crazy Ants Paratrechina longicornis to confirm they have not spread to the outer islands from Diego Garcia.

    While conducting the coconut crab surveys on Vache Marine, Middle Brother and Eagle Island, the introduced house gecko, Hemidactylus frenatus, was recorded on all three islands for the first time. The ecological impact of this species on these islands is unknown. On Eagle Island, a quick site assessment was completed for one of the two mangrove forests on Chagos. While there was evidence of choking of the mangroves by coconut and other invasive species, there was also signs of mangrove recruitment which was encouraging.  

    The species above require management now before their negative impact is irreversible; this is especially relevant on the rat-free Important Bird Area (and potentially Important Plant Area) islands.  This management requires funding, prioritisation, scientific base-lining and justification immediately.  Similar to the demise of the breeding Common Noddy and possibly Sooty Tern, the management of invasive species needs to be the UK FCO top priority before the loss of biodiversity through their negative impact is irretrievable.

    Figure 27: Exotic species, the house gecko Hemidactylus frenatus, documented on Middle Brother

     

     

     

     

  • Pete Carr BIOT Science Expedition 2014 Initial Report Seabird IBAs

    Long-term monitoring of Important Breeding Areas for Seabirds

    Peter Carr, Permian Global

    The primary aim was to continue long-term monitoring of internationally important breeding seabirds with the focus being on the ten designated and two proposed Important Bird Area (IBA) islands that hold > 98% of the breeding populations.  Secondary aims were:

    • Initiate a Sooty Tern Onychoprion fuscatus study to analyse the breeding habitat requirements of this, the most numerous seabird in and, prime ecological indicator of the health of the Chagos Marine Protected Area (MPA).
    • Trial Mataki tracking devices on Red-footed Booby Sula sula to study their feeding and foraging behaviour throughout the Chagos MPA.
    • Monitor the spread of invasive species throughout the Chagos Archipelago.

    General findings

    Eleven of the twelve designated and proposed IBA islands were fully surveyed plus four other islands of ecological importance.  Diego Garcia, the missing IBA was not surveyed due to time constraints, it taking five full days to cover the breeding colonies associated with this island.  The seabirds were having a catastrophic breeding episode, caused primarily by the failure of Sooty Tern to successfully breed.  The Sooty Tern breeding habitat study was successfully initiated but with limited numbers of chicks ringed due to the breeding failure mentioned above.  The Red-footed Booby tracking project was initiated but was severely hampered by the time and location constraints imposed due to the necessity of meeting all scientists’ aspirations on the expedition.  Notes on the spread of invasive species were taken, to be used to steer future terrestrial management plans.  All are dealt with in greater detail below.

    What these scientific research expeditions achieve for terrestrial monitoring is to provide a snap-shot of what is occurring at that time and this caveat is particularly relevant when interpreting dynamic events such as seabird breeding episodes.  For the breeding seabirds of the Chagos the expedition surveys do not provide a definitive figure for the annual breeding populations, as they would in a northern hemisphere environment where there is a defined breeding season and the entire breeding population can be surveyed.  This is because seabirds in the Chagos either breed throughout a calendar year or breed at less than 12 month intervals.  Further, the lack of regular long-term monitoring (including at different times of the year) means that what data is gathered cannot be fully interpreted in a population trend context.  This is because we do not know, for example, how often complete breeding failures as happened this expedition with Sooty Tern, actually occur.  With these caveats in mind, a summary of the results of the key avian indicator species follows:

     

     

    Long-term monitoring of Seabird Breeding

    Sooty Tern Onychoprion fuscata:  This species has had a catastrophic breeding episode.  This should be the most numerous breeding seabird and over 100,000 breeding pairs is the annual expected norm on four to ten islands.  This year (at least to date) 400 pairs bred on two islands.  On Parasol in Peros Banhos 26% of chicks examined held avian parasitic ticks and the main colony of approximately 32,000 pairs deserted at the egg-laying stage.  On Middle Brother, a survey in February 2012 recorded 32,000 breeding pairs.  This year there were less than 300 pairs and these were also tick-infested but to a lesser degree (˃7%). It is unlikely that tick-infestation was responsible for lack of breeding on all islands.

     

    Figure 23: Onychoprion fuscata breeding pairs recorded through February 1996 – April 2014.

    It is clear from figure 23 that much data are lacking and an incomplete picture is presented.  In July 2009 and August 2010 there were breeding episodes that would not have been recorded on “the annual” scientific expeditions.  It is not known if breeding episodes occurred in years not surveyed and crucially, the context of the 2014 tick infestation cannot be assessed in a historical or episodic context.

     

    Figure 24: a) An Onychoprion fuscata chick displaying a tick-infested foot.  b) A dead Onychoprion fuscata chick with ticks.

     

    Red-footed Booby Sula sula:  The three largest breeding colonies (3,000+ pairs) are on Nelson and Danger Island and Diego Garcia and the total annual breeding population is in the region of 10,000-12,500 pairs.  Diego Garcia was not surveyed on this trip as it takes at least five days to cover all the breeding area.  Nelson’s Island held approximately 557 breeding pairs and Danger 400.  Elsewhere there were 1169 breeding pairs. The total of 2,126 breeding pairs falls well short of the expected norm and is a cause for concern.  However, this species has a north to south breeding gradient in that it nests earlier in the northern atolls than further south, therefore both Nelson’s and Danger Island have not reached peak breeding numbers yet.  Further, some birds breed throughout the year and what oceanographic event(s) that trigger breeding is as yet unknown.  Therefore, whilst there has been a decline in breeding numbers in comparison to previous surveys at this time of year, the true extent of the decline cannot be completely recognised without counts from later in this calendar year.

    Wedge-tailed Shearwater Puffinus pacificus: Burrow-nesting shearwaters are notoriously difficult to accurately census, particularly when different counters are employed over the years.  Dedicated shearwater researchers use state of the art heat-sensors or infra-red cameras to ascertain burrow occupancy.  On the positive side, in the Chagos, with the exception of a tiny population on Diego Garcia, all shearwaters breed between November and April and therefore virtually the entire population can be counted by a one-off count in the right month.  Even taking in to consideration the difficulties of accurately counting breeding shearwaters, there appears to have been a ≈ 66% decline in the breeding population since 2012.  This figure is made more relevant by the fact that the same counter, using the same census method has counted the shearwater colonies since 2009.

     

    Figure 25:  Puffinus pacificus breeding pairs recorded through February 1996 – April 2014.

    It is worth noting that Sooty Tern, Red-footed Booby and Wedge-tailed Shearwater are all deep water/pelagic feeders that are reliant to a certain degree on pelagic fish, i.e. tuna, to locate and catch prey.  It is possible that the decline in numbers of these three species could be associated with problems with their pelagic feeding associates.  This hypothesis would require further research to assess.

     

    Brown Booby Sula leucogaster:  This beautiful bird produced an annual record count of over 740 breeding pairs on North Brother, the majority at the egg-laying stage.  There is one other large colony in the Chagos, on Danger Island.  This colony only held 38 breeding pairs and these were all at the fledgling stage.  In addition there were between 50-70 recently fledged juveniles hanging around the colony area.  With the addition of smaller numbers breeding on three other islands the total Chagos breeding population in 2014 stands at approximately 850 pairs.  This a significant portion of the total Indian Ocean population.

    Lesser Noddy Anous tenuirostris:  This species also appears to be sustaining its breeding population in the Chagos.  It is problematical to survey due to an erratic/unknown breeding season.  Counts throughout the year since 2008 have revealed an annual breeding population in the region of 35,000 – 40,000 pairs centred upon three major colonies on Nelson’s Island, South Brother and Petite Ile Bois Mangue and smaller colonies on many other islands.  This year’s survey has coincided with breeding in these three main colonies and the total recorded has been comfortably above 35,000 pairs.

    It is worth noting that Brown Booby and Lesser Noddy are regarded as inshore feeders and their present successful breeding status may be a reflection of the health of the banks, reefs and shoals of the Chagos MPA.

    Common Noddy Anous stolidus:  This species continues to be of grave concern in the Chagos.  In the 1970’s, Nelson’s and Danger Island and Sea Cow each held terrestrial breeding populations of 10,000+.  In 1996 there were c. 42,000 breeding pairs recorded.  These numbers had declined to the low thousands by 2006 and terrestrial breeding had all but ceased by then.  This situation has not changed and the annual breeding population has remained at under 2,000 pairs.  Crucially, this species no longer breeds in dense colonies on the ground.  It now breeds in isolation in trees.  Whilst still common, the population is likely to be in very serious decline but has not manifested itself yet due to longevity. 

    Assessing the Breeding Habitat Requirements of the Sooty Tern Onychoprion fuscatus

    The Sooty tern is the cornerstone of the designation of Important Bird Areas (IBAs) in the Chagos Archipelago with eight of the twelve IBAs being dependent upon this species for designation.  However, surveys conducted since 2006 have demonstrated that not all islands are bred upon every year and Carr proposed in 2011 in British Birds and again in 2013 in Coral Reefs of the UKOTs that this designation system be changed to clusters of islands rather than individual islands.  This system better reflects the bird’s actual use of the islands for breeding.  This study aims to prove the shifting nature of the breeding colonies by individually ringing flightless chicks on breeding islands and then recapturing them at a later date in a breeding colony.  This study was successfully started on the 2014 expedition with 135 chicks ringed on two breeding islands.  It was hoped this figure would have been substantially greater but was hampered by the catastrophic breeding failure of this species during the period of the visit.

    Testing Mataki Tracking Devices on Red-Footed Booby, Sula sula

    The aim of this study is to track breeding Red-footed Booby on feeding and foraging flights to better understand their use of the Chagos MPA.  It may also reveal pelagic fish movement in and through the MPA as Red-footed Booby is a near obligate-associate with pelagic fish when feeding.  This trial was successfully started with devices attached to two adult birds.  No data were derived from these tags but the experience gained from handling the birds and managing the tags will prove invaluable in this ongoing study.

     

    Figure 26:  Attaching a Mataki transmitter to an adult Red-footed Booby.

    Conclusion

    The surveys this year demonstrated this has been a season of highs and lows for breeding seabirds.  The take-away point is if we are serious about conserving birds (and other terrestrial organisms) in the Chagos we have to understand their ecology, part of which is their breeding phenology.  This aspiration is still a long way off and can only be achieved by regular surveys throughout the year over a long period of time.  Only by knowing such simple things as when and where a seabird breeds, how often and in what numbers, what on an island is impacting their breeding and most important, what oceanographic events trigger breeding, will we really be able to implement effective conservation management plans.  Sadly, time may be running out for effective conservation measures in the Chagos for Common Noddy and Sooty Terns.

     

     

  • Pete Carr BIOT Science Expedition 2014 Initial Report Coconut Crab Surveys

    Population Assessment of the Coconut Crab, Birgus latro

    Peter Carr, Permian Global and Heather Koldewey, ZSL

    A base-line study of a non-harvested population of coconut crab, Birgus latro, in a native, mature, mixed forest was undertaken on Diego Garcia in 2011 by a US scientist.  It is thought this base-line represents “the ideal population” only achieved in conditions of plentiful food, adequate recruitment and where there is no harvesting. For the first time, coconut crab surveys were conducted in the northern atolls to determine population dynamics for this IUCN Red-Listed Data Deficient species.

    On this expedition, three islands each were surveyed (Vache Marine, Middle Brother, Eagle) using the same methodology as that used in previous Diego Garcia surveys. After dark, starting at 1930 hours, 25 x 30m transects were conducted using DISTANCE methodology, involving remaining on islands overnight. Data were collected on the size, sex and weight of crabs along the transects. The islands were selected for their size, vegetation composition and rat presence/absence.  The results are still being analysed, however, there appears to be a possible correlation between island size, vegetation composition and rats.  The hypothesis being tested is that rats on small, vegetation impoverished islands predate adult coconut crabs.

     

     

    Figure 22: Pete Carr undertaking night surveys of coconut crab

     

     

  • Dr Elizabeth Widman Initial Report BIOT Science Expedition 2014 Sea Cucumbers

    Long-term monitoring of Sea Cucumber Populations

    Dr Elizabeth Widman, University of Warwick

    Background

    Holothurian (sea-cucumber) surveys lead by Professor Andrew Price were conducted in 2006 (76 transects Price et al. 2009) and 2010 (68 transects Price et al. 2013). Due to illness Prof Price was not able to participate in the 2014 expedition and I continued the long-term monitoring surveys in his absence using the established survey sites and sampling protocol (see below).

     

    Methods

    The sites identified for resampling were those that had been surveyed in both 2006 and 2010 (68 sites in total). In total 63 of the targeted 68 sites were resampled. Surveys at two sites in the northwest lagoon of Diego Garcia (Site 12 and 13 Price et al. 2009) were attempted but visibility proved too poor, two sites at North Brother were attempted (sites 42a and b Price et al. 2009) but rough conditions did not allow for an accurate survey to be undertaken, and one transect in the Salamon atoll (31c Price et al. 2009) was too deep to make accurate identifications and was therefore abandoned.

     

    At each site a 2m x 100m (200 m2) transect was surveyed and the abundance and identity of any holothurians, substrate type and depth were recorded. If accurate identifications could not be made in the field, photos were taken and taxonomic experts consulted. GPS tracks were recorded for most transects, which will facilitate future resampling. 

     

    In addition to the long-term monitoring of shallow habitats outlined above, photo-transect surveys were taken at 27 sites and will be used to assess the holothurian populations present in deeper reef habitats (25m - 5m). This will complement the long-term shallow surveys nicely by providing insight on the diversity and abundance of holothurian populations in deeper reef habitats across the Archipelago, something that has not, to my knowledge, previously been assessed.

    Output

    The 2014 holothurian data has now been compiled and added to survey data from previous expeditions. Statistical analyses are currently being undertaken to assess the temporal variability across the 63 sites and 5 atolls (Salomon, Peros Banos, Great Chagos Bank, Egmont, and Diego Garcia) and a manuscript summarising the results will be submitted for publication (target journal: Aquatic Conservation: Marine and Freshwater Systems). This publication will provide a summary of the status and potentially indicate any evidence of continued poaching of holothurians in Chagos. GPS tracks of transects and survey sites will be incorporated into the Chagos Resource Portal.

    Figure 21: Juvenile seacucumber (Pearsothuria graeffei) near Danger Island on the Great Chagos Bank. Remarkably, juveniles mimic the exact colouration of the toxic nudibranch (Phyllidia varicosa). Photo credit: Dr Courtney Couch

     

     

  • Dr Ronan Roche BIOT Science Expedition Initial Report 2014 Parrotfish and Reef Erosion

    Assessing the Contribution of Parrot Fish in Reef Erosion

     

    Dr. Ronan Roche, Bangor University

    Continuing work started during the 2013 Darwin expedition, parrotfish bite rate data were collected whenever possible during dives, and whilst snorkelling. Based on the previous year’s data, collection the Steephead parrotfish (Chlorurus strongylocephalus) was chosen as the parrotfish species on which to focus research efforts.

     

    The net calcium carbonate accretion/erosion state of reefs worldwide is an issue of increasing importance, as evidence shows that reefs in important locations are now in net erosional status. Work which will be carried out in the Darwin Initiative 2015 expedition will gather information to allow calculation of the rate of calcium carbonate production at sites around Chagos. Parrotfish are corallivorous, and so form an important part of the calcium carbonate cycle on reefs, by consuming and excreting coral skeletal material. To calculate the volume of coral skeletal material removed, information on parrotfish abundance and bite rate frequency must be collected.

     

    During the 2014 expedition I recorded parrotfish bite rate data at fourteen sites around the Chagos Archipelago, Each parrotfish was followed underwater for five minutes, and size, life-cycle stage, number of bites taken, and the nature of the substrate targeted were recorded. Twenty nine parrotfish were observed over 145 minutes.

          

     

    Figure 20: a) Parrotfish bite marks on coral head

     

    b) Steephead Parrotfish Chlorurus strongylocephalus

     


  • Dr Melita Samoilys BIOT Science Expedition 2014 Initial Report

    Diversity and population abundance of reef fishes

    Melita Samoilys, CORDIO and Heather Koldewey, ZSL

    Objectives

    The objectives of the reef fish surveys were to:

    i) measure the diversity of reef fishes in Chagos using a standardised method used in the Western Indian Ocean (WIO) based on an inventory of all species from a pre-defined list of 19 families;

    ii) measure abundance and biomass of a broad cross section of the fish community to determine the densities and biomass of key trophic groups considered important in coral reef resilience;

    iii) estimate the abundance and biomass of groupers as taxa that are generally highly vulnerable to overfishing and consequently depleted and threatened in most coral reef regions. Chagos may represent some of the most pristine populations of coral reef groupers in the world

    Having recently quantified coral reef fish diversity and population abundance in Madagascar, Comoros, Mozambique and Tanzania, a core region representing the highest biodiversity in the West Indian Ocean (WIO), the Chagos survey provided a unique opportunity to collect comparable data to this WIO dataset. Chagos potentially may provide baseline or reference values as Chagos reefs arguably represent reefs least damaged by humans in the Indian Ocean.

    Methods

    Species diversity

    Reef fish diversity measures were recorded using a method standardised for the WIO which is designed to provide sufficient breadth of species sampling, while remaining practically feasible for relatively rapid dive surveys across a number of locations. It is based on compiling a complete species inventory of 19 families at each location. Family selection was based on a number of diversity criteria, encompassing a) most speciose; b) known indicators of aspects of fish communities; c) fishery importance; and d) taxonomic diversity. These families include potentially around 460 species in total from the WIO (Allen in McKenna and Allen 2005, Davidson et al. 2006, Obura 2004, Samoilys 1988). This was considered to be broad enough and diverse enough to capture patterns in diversity of fishes within the WIO region. For example, the potential species list represents 51% of the total number of coral reef species from 92 families reported from Madagascar (Allen 2005), one of the most diverse coral reef areas in the WIO. At each location two 30-40 minute dives were completed recording presence/absence of all species from the 19 families. In total 31 dive sites were surveyed giving species richness measures for 16 locations.

     

    Fish abundance and biomass

    Fish abundance and size class data were recorded across pre-selected taxa that can be assigned to different trophic groups with a strong focus on herbivory (after Green and Bellwood 2009), but also including other functional groups of fish, to provide a broad and representative cross section of the reef fish community. The data can be used to ask general questions about the status of reef fish populations as well as specific questions about the densities and biomass of key trophic groups considered important in coral reef resilience. Thus, fish species were categorised across seven broad functional trophic groups (Samoilys and Carlos 2000, Obura and Grimsditch 2009), with the herbivores further broken down into the six functional groups (Green and Bellwood 2009). Most fish were recorded to species level so that they could be easily assigned to the correct trophic group. Fish densities and size classes were estimated using 50 x 5 m transects on SCUBA, a standard method set since the 1980s. Sizes of all species that were >10cm TL were estimated to obtain biomass values based on published length–weight relationships. In total 31 dive sites were surveyed giving 13 fish abundance and biomass measures for 13 locations. A further restricted list of species were counted using long timed swims (10 mins) to estimate the abundance and biomass of species that are a) roving or pelagic taxa which are generally though not exclusively large that associate with coral reefs: the Scombridae, Carangidae and Carcharinidae; b) contribute significant  biomass on a reef such as Cheilinus undulatus, Bolbometapon muricatum and other large excavating Scarinae, are in the top trophic categories of piscivores or omnivores such as large (> 56cm TL) serranids, lutjanidae and lethrinids.

    Preliminary results and observations

    Species diversity

    Species diversity is lower in Chagos compared with the northern Mozambique Channel (NMC) of high diversity in the WIO, with total species counts in the order of 102 per site, compared with 135-150 in Cabo Delgado, Mozambique and Mafia island, Tanzania. Around 214 species known from the WIO were not observed in Chagos, with a total species richness of around 226 recorded across all sites, compared with 335 in the NMC. Data are still being analysed so these figures are provisional and not final.  2-3 species ranges have been extended and the Chagos Fish List compiled by Sheppard from various surveys since the 1970s will be compared.

    Fish abundance

    The fish abundance and biomass data require analysis, but provisional observations suggest that fish abundance was generally higher than observed elsewhere in the WIO, particularly for scarids and acanthurids, but with certain key taxa absent or rarely observed, overall biomass was not as high as expected. However, what was noticeable was the large size of the Plectropomid groupers, with 100cm TL frequently observed in Plectropomus laevis, which is the maximum size this grouper attains. This suggests little to no fishing pressure on this species. These grouper were also abundant, being present at almost every site. Reef sharks were relatively common – seen on every dive - when compared to other locations in the WIO, where they are very rarely observed. This shows the generally dire situation for reef sharks in the WIO, as these fish are known to be very depleted in Chagos (Graham et al., 2010) and poaching continues to be a problem. Grouper densities were patchy and require analysis to try and determine the reasons for this. Notable was the camouflage grouper, Epinephelus polyphekadion, which was very common and may reflect natural population abundance of this species in the absence of fishing. This fish is extremely unwary of divers and therefore very vulnerable to spearfishing. It is rarely or never seen in mainland east Africa.

     

    Figure 19: Chlororus enneacanthus and other scarids in Middle Brother lagoon.

  • Prof Charles Sheppard and Anne Sheppard's initial report on Sea Temperature recording BIOT Science Expedition 2014

    Documenting Sea Temperature in Chagos

    Prof Charles Sheppard and Anne Sheppard, Warwick University

    After the severe warming event in the Indian Ocean in 1998 that caused such widespread coral mortality, we installed temperature data loggers at various points around all five Chagos atolls in 2006.  Since then, the data have been downloaded and the loggers reinstalled during each expedition.  A publication has resulted from initial data(Sheppard, 2009) that introduced the remarkable (and so far unexplained by oceanographers) temperature plunges that occur on all ocean facing slopes. The data loggers are maintained and replaced on each expedition, and this year several new loggers were also installed.

    The loggers are at 5, 15 and 25 metre depths, but not always all 3 depths at all sites. For example in exposed seaward sites the 5m loggers do not survive the storms and some lagoon sites do not reach 25m depth.  Recovery rates are high due to the system of installing them with GPS fixes.  Presently there are 15 loggers recording temperature at 2 hourly intervals.

     

     Figure 15: A logger at 15 metres in Peros Banhos lagoon.  Despite being difficult to see, this one has been found on each expedition (2010, 2012, 2013 and 2014) the data downloaded and the logger replaced.

    Figure 16: Rebar stakes are hammered into the reef onto which the loggers are secured.

    Figure 17: The logger is attached to the stake inside a protective tube to stop it being damaged by parrotfish.

    photo J Slayer

    Figure 18: The newly installed logger at 25m at Ile du Coin, Peros Banhos.

     

  • Dr Elizabeth Widman Initial Report BIOT Science Expedition 2014

    Scleractinian Coral Functional Diversity Surveys

    Dr Elizabeth Widman, Warwick University

    Background

    Investigations into how species diversity relates to system-level properties, such as ecosystem functioning, have been largely unsuccessful and have failed to produce general principles (Lawton 1999; Simberloff 2004; McGill et al. 2006). To address the shortcoming of species-only approaches a renaissance of sorts is taking place in community ecology (McGill et al. 2006): species-level data is being supplemented with trait-level data in some systems. It has been discovered that functional trait diversity plays an important role in: ecosystem processes (Hooper et al. 2005), the resilience of ecosystems to environmental stressors (Folke et al. 2004), and the provision of ecosystem services (Díaz et al. 2007). While trait-based approaches have shown great promise in other branches of ecology, such as plant ecology (Shipley et al., 2006) it remains largely unexplored in marine and especially coral reef ecology.

    One major advantage in quantifying the abundance and diversity of traits rather than species alone is that it allows one to link empirical measurements on the species level directly to macro-scale functioning (Cadotte et al. 2009). Another key reason for embracing trait-based approaches in coral reef ecology is that focusing on trait diversity bypasses taxonomic uncertainties brought about by genetic and genomic tools (Fukami et al. 2008) while retaining ecological identities.

    Gaining an understanding of what makes reefs in Chagos far more resilient to climate related stressors, compared to other regions of the Indian Ocean, is central to its appropriate management. In turn gaining such insights require that we understand and quantifying organismal fitness relative to the changing environmental variables associated with climate change (i.e. increased water temperatures, acidity, storm frequency and intensity). The traits which species possess, their environmental plasticity, and their combinations are the ultimate determinants of whether a species will survive, thus, any monitoring and research program operating under the vision of conserving resilience must logically account for, on some level, the species traits presents on the reefs of the Chagos Archipelago.

    Constructing a coral trait-database for Chagos (see output section) and conducting a functional diversity survey on the Chagos archipelago are the first step towards understanding the coral species traits and trait-combinations that are present on the reefs. Explorations into what different trait diversities and combinations mean in terms of resilience and/or resistance to future stress events can then be explored.

    Methods

    Analytical approaches used in assessing a broad range of functional diversity metrics require a minimum of two datasets: a species x site matrix (i.e. species site composition) and a species x trait matrix. Species composition was determined for 27 sites using an established phototransect methodology (Widman 2012). Phototransect sites were surveyed across five atolls (Salamon, Peros Banhos, the Great Chagos Bank, Egmont, and Diego Garcia) and at 6 depths (25m, 20m, 15m, 8m, 5m, and 2m) where possible. For reference each image is geotagged (by syncing the camera timer with a GPS on a buoy which is dragged throughout the dive) and also depth tagged (by including a dive computer in every image; see Figure 1 for details). The species composition for each site will be determined by analysing the images using CPCe software (Kohler & Gill).

     

    Figure 14: Overview of the underwater sampling method (far left diagram). Images of the reef surface were taken along a transect from a known distance, measured by a PVC pole attached to a camera rig (centre image). A GPS unit fixed to a floatation device (far right image) was towed throughout the dive in order to record the position of each image taken.

    Output

    A trait database will be constructed for the coral species in Chagos using the species list compiled by Doug Fenner on the 2014 expedition and a number of existing coral trait databases (i.e. Widman 2012 2014). Using this trait database, along with the species composition that will be derived from analysing the photos, a battery of trait-based analyses will be undertaken to understand the functional composition of reefs on the Chagos archipelago.

    The relationship between coral trait diversity and other relevant datasets collected on the same reef sites during the 2014 expedition will be explored. These datasets include fish diversity (Dr Samoilys and Dr Koldewey), coral disease (Dr Couch), and temperature history (Prof Charles Sheppard and Anne Sheppard). Future collaborations have already been discussed to maximise the depth and breadth of this functional analysis.

    When the analysis is complete the result will be an archipelago-wide survey of reef functional composition. This will improve not only our basic understanding of how the reef functions but also give insight on macro-ecological properties such as functional redundancy and resilience to specific stressors. Ultimately, understanding macro-ecological reef properties such as ‘functioning’, resilience and resistance to stressors helps inform managers and decision makers.

     

     

  • Dr Courtney Couch BIOT Science Expedition 2014 Initial Report

    Assessing Coral Disease Prevalence, Severity and Susceptibility

    Courtney Couch, University of Hawai‘i

    Background

    Although disease is a natural component of healthy ecosystems coral disease has steadily increased during the last four decades and is considered one of the major contributors to global coral reef degradation. Originally restricted to the Caribbean, the ecosystem-wide effects of disease, acting synergistically with other environmental stressors are now threatening the regions of the Indo-Pacific and Indian Ocean. Large marine protected areas such as the Chagos archipelago and others within the Big Ocean Network provide a unique opportunity to study the effects of climate change on coral diseases and overall reef health in the absense of local anthropogenic stressors such as pollution and overfishing. Assessments conducted in Chagos in 2006 suggest that coral disease prevalence is low compared to other inhabited regions. My primary goal during the 2014 Chagos expedition was to develop a coral disease monitoring programme that is consistent with programmes in other regions to facilitate  broad-scale analyses and understand the processes driving disease. Specifically I: (1) Assessed the spatial variation in prevalence and severity of coral disease and other biological interactions (e.g. algal overgrowth, predation, sedimentation) and identify disease hot spots; (2) Assessed which coral taxa were most susceptible to disease; (3) Collected tissue and mucous samples from healthy and diseased tissue for histopathological and microbial analysis; (4) Established permanent transects at a subset of sites.

      

     Figure 12: Courtney Couch conducting a coral health and disease survey at Ile de la Pass in Peros Banhos Atoll. Photo: J. Schleyer

    I conducted coral health and disease surveys at a total of 31 sites in Salomon Atoll, Peros Banhos Atoll, Blenheim Reef, Three Brothers Islands, Eagle Island, Danger Island, Egmont Islands and Diego Garcia Atoll. At each site, I surveyed two 18m belt transects along which I counted and identified all coral colonies, as well as recorded signs and severity of disease, bleaching and other biological interactions. These data will be used to calculate prevalence (# of coral colonies with a condition/total # of colonies) of each condition across all coral taxa and by taxon. I also took photoquads along each transect to estimate % coral cover. To confirm field observations and identify potential agents involved in these diseases, I collected 50 samples of diseased and healthy tissue, which will be sent to laboratories in Hawaii and London. To lay the framework for future surveys, I established 6 permanent transects in Diego Garcia along which I mapped and photographed diseased colonies to quantify disease progression.

    Preliminary Observations

    Overall most of the study sites appeared quite healthy with low disease prevalence. I recorded five disease types including white syndrome, sub-acute tissue loss, multifocal tissue loss, growth anomalies and skeletal eroding band. Disease susceptibility varied considerably across coral taxa with disease recorded on 9 scleractinian coral families, most notably Acroporidae, Pocilloporidae, Poritidae and Faviidae. In addition, corals were also minimally affected by partial bleaching, Drupella cornus predation, algae and sponge overgrowth, physical damage (mostly on exposed seaward sites) and smothering from sedimentation (lagoon sites). Coral bleaching was highly patchy across the reefs and manifested as partial bleaching of the colonies rather than mass bleaching observed during thermal stress events. 

     

    Figure 13: (A) Acropora white syndrome, (B) Porites sub-acute tissue loss, (C) Acropora multifocal tissue loss, (D) Acropora growth anomalies, (E) Stylophora skeletal eroding band, (F) Algal overgrowth, (G) Drupella predation, (H) Sedimentation stress, (I) Partial bleaching. Photos by Courtney Couch

    One of my primary discoveries during this expedition was the presence of Acropora white syndrome throughout the Archipelago. White syndrome is characterised by healthy tissue bordered by a region of white skeleton next to algae colonized skeleton. This disease affects a wide range of coral taxa and is found across the Indo-Pacific and Indian Oceans and can cause rapid and widespread colony mortality. Acropora white syndrome, specifically, had low overall prevalence and was nowhere near outbreak levels, but was locally severe at several sites suggesting that not all sites are affected equally.  This disease also appeared to target large/older (>40cm) tabular Acroporids, which is not only concerning given this group’s important reef-building status, but may help to explain the recent die-off of large tabular Acroporids in Chagos. It is important to keep in mind that this disease has been found in other remote regions such as Palmyra and the Northwestern Hawaiian Islands and has been strongly linked with thermal stress.  Therefore, it is crucial that we continue monitoring this disease in Chagos to understand how fast it is spreading, which reefs are most affected, the relative importance of environmental stress and its long-term implications on reef structure and function.

     

     

     

     

     

     

  • Dr Doug Fenner's initial report from the 2014 BIOT Science Expedition

    Coral Species Diversity and Abundance

    Douglas Fenner

    This research project recorded coral species and relative abundance at each dive site, plus record some information on coral diseases.  This was conducted on a total of 30 dive sites.  I began each dive at the lower end of the allowed depth range, approximately 24 meters depth, then spent my dive slowly working my way shallower, ending under the dive boats in about 10 m of water after about 60 minutes.  I attempted to photograph all coral species multiple times, and particularly concentrated photography on corals I have not seen before, have not been reported before for Chagos, and/or I cannot identify.  I also photographed many diseased corals, particularly those that look different from those I have photographed previously. I took some pictures of scenes, showing what the reef was like, plus some photos of fish or other interesting marine life.  I took a total of about 2800 underwater photographs.  I collected 30 small samples of corals that I could not identify or to confirm species that I was not sure of for further analysis.

    I recorded a total of about 143 species of coral (that number will increase slightly when I examine my photographs), 32 of which have not previously been reported from Chagos, and 16 of which are outside their known ranges.  Two previous lists of coral species, one by Sheppard (1999) and the other by Obura, each found about 220 species, but when combined had a total of about 310 species.  Veron has reported a total of 275 species, but his sources need confirmation (he has not been to Chagos).  I found an average of about 40 coral species per dive site.  Previous studies by the author found an average of 35 species per site in Rodrigues, 65 species per site in the Andaman Islands, and 49 per site in SW Madagascar.  One species which was first described in 2003, Plerogyra diabolotus, was found which is the first record I am aware of other than the type location which was in Borneo.  Also, Parasimplastrea sheppardi was found for the first time in Chagos.  It was first found in Oman by C.R.C. Sheppard and is known from the Arabian Peninsula.  Also, the author reported it from Rodrigues in 2004.  This is the farthest east it has been recorded so far.  It may be more widespread in the Indian Ocean.

     

    Blenheim and Paros Banos had the most coral species and Salomon had the least, however the number of sites was small enough that these results are likely not significant.  Outer slopes and lagoon sites had the same number of species as shown in figure 10.

     

     

    Coral diseases were much more common than reported from a survey in 2006.  The most common and threatening disease was “white syndrome”. This disease kills coral that it infects, and often kills rapidly.  Although it sometimes stops before killing an entire colony, it kills many colonies.  It primarily infects tabular Acropora colonies. There were large numbers of tabular Acropora colonies that grew after the 1998 El Niño mass coral bleaching, primarily on the upper reef slope and on patch reefs.  Acropora paniculata was the most common table, and A. clathrata was much less common.  There are many dead table corals at many sites, which may have been produced by senescence, and/or white syndrome.  This disease is throughout the archipelago.  A second disease is a tissue loss disease that affects branching corals such as Pocillopora and Stylophora pistillata.  It is also widespread in the archipelago and can be lethal for a colony, but is not common enough to have killed large numbers of colonies.  Growth anomalies, which have been called “tumours” in the past, are common some other places such as American Samoa on tabular Acropora and massive Porites colonies, but were rare in Chagos.  Two types of growth anomaly were seen and photographed for the first time here, but both were extremely rare, being found only in one colony each, out of hundreds or thousands of colonies seen of the coral species they were found on.  Three kinds of discoloration were also found, but they were also exceedingly rare.

     

  • Prof Charles Sheppard's initial report from the BIOT Science 2014 Expedition

    Assessment of Coral Cover

    Prof Charles Sheppard and Anne Sheppard, Warwick University (with support from David Curnick, ZSL/UCL)

    We collected the first coral cover data from the Chagos Archipelago in 1978 and then again in 1996.  After the Indian Ocean warming event in 1998, we have regularly monitored the coral cover in the same locations in Chagos (2006, 2010, 2012 and 2014) to determine how well Chagos' reefs have recovered from the 1998 trauma, especially in comparison to other Indian Ocean sites.

    During this expedition we surveyed 25 sites at depths of 25, 20, 15, 10 and 5 metres and collected coral cover data from 718 quadrats, covering 180 square metres of reef in both lagoon and seaward locations.  Quadrats were collected at all five islanded atolls, from ocean facing slopes facing the strong  southeast tradewinds to more sheltered western and northwestern ocean slopes, and from several lagoon areas of varying degrees of shelter.  Many of the reefs were sampled where temperature loggers were also deployed.

    In each quadrat, data were collected, where relevant, on the number of coral colonies, number of coral interactions, dominant coral species, % coral cover, % soft coral cover, % algae, % sand, % sponge, % crustose coralline algae (CCA), % bare space and % dead coral. An estimation of overall cover at each depth was made in case the quadrats selected were not representative of the overall area.

    Figure 6: A simple folding metre stick used as an effective quadrat

     

    These data will be analysed and the results compared with the data collected for the preceding 35 years, to determine trends.

    Figure 7: In an example quadrat, showing 2 coral colonies, 1 coral interaction, 60% live coral, 30% algae,5% CCA and 5% sand.

     

     

    Figure 8: According to circumstances sometimes the quadrats were laid along a transect tape and other times they were laid randomly.

     

                                                                                                                                                   

     

  • Dr Ronan Roche BIOT Science Expedition 2014 Initial Report

    Understanding Coral Reef Structure

    Dr. Ronan Roche, Bangor University

    During the Darwin Initiative March/April 2014 expedition I built on the work carried out during the February/March 2013 expedition to examine reef structure to provide data that complement video transect surveys.

    Reef structure data collected followed the protocol developed during 2013, in which the following variables were collected at 5-meter depth intervals during the dive:

    • reef slope
    • abundance of Acropora sp.
    • proportion of Acropora sp. which are recently dead
    • broad scale reef rugosity
    • coral colony scale rugosity

     

    Slope data provide information on the context of video coral reef surveys, to allow correct interpretation of the video footage obtained on the expedition. Acropora species are one of the most abundant branching species on many of the reefs around the Chagos archipelago, and provide a refuge for numerous species of reef fish. The proportion of dead Acropora corals can be used as an indication of reef health, and provides a complementary visual assessment to video surveys. This variable may also provide information on impacts such as storm damage to reefs, crown-of-thorns starfish feeding on branching corals, coral disease, or coral bleaching events.

     

    Figure 4: Ronan Roche surveying reef rugosity, here encountering a cave on the reef slope at Egmont atoll

     

     

    Rugosity assessments are important as reefs with higher rugosity provide a greater range of habitats, particularly for reef fish and generally exhibit higher biodiversity. Broad scale rugosity is an indication of the degree to which the reef surface undulates and has a topography that includes features such as caves or a spur and groove system. Colony scale rugosity is the degree to which the corals at a site are fully developed and contribute complexity to the reef structure.

     

    Twenty-four sites were surveyed utilising this methodology during the March/April 2014 expedition, with contemporaneous underwater video survey. The Chagos archipelago contains sites which range from those with extremely complex reefs with high levels of rugosity, to those which are currently less developed and have minimal levels of rugosity. These differences primarily relate to the position of sites inside or outside of atoll lagoons, and to the degree of exposure to strong currents and wave impacts, whilst remaining differences are likely the result of storm impacts and biological impacts such as bleaching and disease. Initial examination of the data collected from the 2014 expedition indicates that many sites are being impacted by large dead Acropora colonies with ‘table’ morphology moving down reef slopes during storm events.

     

     

    Figure 5: Dead Acropora tables at Egmont atoll

     

  • Dr John Turner Science Expedition 2014 Initial Report

    Video Archive for Long Term Monitoring of Coral Reef Benthic Communities:   

    John Turner and Ronan Roche, School of Ocean Sciences, Bangor University, UK.

    During the 2014 Expedition, John Turner and Ronan Roche continued to develop an archive of video of coral reef benthic community structure across depths at sites throughout the atolls.  The aim is to produce a record that can be analysed and compared with video records made at the same sites in 2006, and for comparison in future years.

    The reefs of Chagos represent an important reference site because they are remote from human activities that cause impacts, such as overnutrification, resource extraction and habitat modification.  However, they are exposed to impacts caused by change in climate such as ocean warming, storms and ocean acidification.  The reefs provide a bench mark for observing the effect of changing conditions in the absence of direct human impact, and indicate how relatively intact and functional reef communities respond to these conditions.  Previous studies have shown that benthic cover, especially of hard corals, reduced following bleaching related mortality after warming events in 1997, 2003 and 2005 but that Acropora corals re-established across the shallow reef slopes and terraces.   Although benthic cover measurements were made on the first expeditions in the 1970s, photography and video techniques were limited, and it is difficult to compare the state of today’s reef communities with those of the past.  However recent investigations have shown that visual surveys and video surveys provide comparable measures of cover, and therefore a video archive can provide important data for assessing change.   Video recording has a number of advantages over traditional survey techniques; the main advantage being that a relatively large tract of reef can be recorded during one dive and imagery can be then be analysed in the laboratory without the constraints imposed on an observer underwater.  Because many randomly grabbed frames (equivalent to sampling from quadrats) can be assessed from video, the sites need only be approximately located because sampling is representative of the reefs.

    The project tests the hypothesis that the reefs of Chagos are highly resilient because they are functionally and structurally intact, and that the reef communities are returning to pre bleaching levels of cover and development.  In addition, the video archive will be used in collaborative work with other expedition teams, for example to test the hypothesis that no diseased corals were present in 2006, but are now evident on all reefs.  Diversity and abundance of grouper and other large reef fish species were recorded on the same reefs by the fish team, and the video data will be used to assess topography/rugosity as a measure of complex reef habitat for fish.  The seaward and lagoon sites at Salomon, Peros Banhos, Great Chagos Bank (including Nelson, The Brothers, Eagle, Danger Island), Egmont and Diego Garcia were surveyed, most of which were first recorded using video in 2006.   Some new sites were added (e.g. at Blenheim – a submerged atoll) for future comparisons. Accurate site identification has previously been confounded by poor position fixing (probably due to inferior GPS technology in 2006; user-error in ensuring best satellite configuration and possibly transfer errors in recording positions), and therefore a database of monitoring sites was established by carefully recording site positions using a high specification Garmin Montana GPS with built in camera to record the nearest land feature where appropriate. 

    Ten minute sequences of video were recorded across 5 m depth intervals from 25 m depth to 5 m depth using a Sony HDR 550 video camera  in a Light and Motion Blue Fin housing equipped with a Fathom 90 wide angle port lens and Sola 1200 lumen video lights (figure 1).  Scale was provided by

     

    Figure 1: John Turner with underwater video camera equipped with wide angle lens, LED lights and red lasers.  A Go Pro camera mounted on top of the video housing recorded habitat scale images at 30 second intervals

    two red lasers which projected red dots 10 cm apart on the video image. Approximately 80 wide angle habitat images were recorded randomly on each dive by a Go Pro Hero 3 camera with red filter and set to record high definition images at 30 second intervals.  In addition, close up digital photographs were recorded to ‘truth’ the video, and observations of reef topography and large scale rugosity were recorded (see report by Ronan Roche).

    Twenty four sites were surveyed in 2014, accounting for over 55 hours underwater and 24 hrs of video records, 2200 Go Pro habitat images and about 2000 truthing images.  15 of these sites were visited in 2006, 12 in 2013 and 8 sites were new to the archive.  It is anticipated that the sites surveyed during the 2013- 2015 expeditions will duplicate all survey sites recorded in 2006.

    Video sequences from four 5 m depth intervals (5-10 m, 10-15m, 15-20m and 20-25m) from a sub group of sites will be compared between 2013 and 2014, but most emphasis will be placed on comparing current data with 2006.   Fifty frame grabs will now be randomly taken from each depth interval at each site using Pinnacle software, and these will be imported into CPCe software (NCRI Florida) and overlaid by 16 randomly generated points.  The substrate, benthic life form, and where appropriate genus and species underlying each point are then automatically collated in an Excel spreadsheet using tab keys in CPCe, and the spreadsheet data is then imported into statistical software for analysis.  Frame grabs can be moved frame by frame to assist in identification, and the ‘truthing’ images will be used to identify species where video image resolution is insufficient.  The Go-Pro images will provide reef descriptions and context, especially for reef fish habitat.  In a separate analysis, every video sequence will be run and presence of diseased coral will be recorded, with extent in colony and size of colony assessed. 

     

    Figure 2: A video frame in which live and dead coral is evident, including some Acropora tables showing signs of disease, and dead standing tables close to collapse.  The red laser dots provide a scale of 10cm in the foreground of the image.

    A preliminary review of the video archive shows that Acropora coral colonies are now less abundant on most reef terraces throughout the atolls, and many of those remaining display signs of disease or have died.  At present, we do not know whether these corals have perished due to old age, bleaching, disease or storms, or a combination of these factors.  Even dead standing Acropora tables appear to have been removed from exposed reefs, probably being swept off the steep slopes by storms. This reduction in reef structure and habitat may have an effect on the reef fish communities.  On some reefs it is evident that small and diverse corals are replacing the Acropora tables, and it is probable that these will develop into a new and more diverse community with time.  Of concern is that some of these corals also display symptoms of disease.  Recruits were observed on dead standing corals, but many of these will be lost when the dead coral framework collapses.  Last year, there was very high mortality in corals below 15 m in Salomon atoll lagoon, probably due to a warming event which caused warm dense seawater to sink in this relatively enclosed atoll, and to kill deeper corals.  However, some recovery was evident in corals below 15 m depth this year, which may be an indication of resilience and is an encouraging signal.

    Figure 3: A randomly recorded image from the Go-Pro camera to illustrate reef slope community structure which will be used to provide context for fish habitat descriptions.

  • 14 04 17 Spreading to the wind - BIOT Science Expedition 2014 Day 21

    Spreading to the wind

    The last three days have completed our time in BIOT ending in an epic day packing all of our science and dive gear away until next years science expedition comes round. After an incredibly busy three weeks in the British Indian Ocean Territory our expedition participants have dispersed around the world. Kenya, Hawaii, American Samoa, Ireland and the United Kingdom being amongst the return destinations for our international crew. Whilst wishing everyone a safe return home it is worth looking back at what we have achieved in our time in the Chagos Archipelago.

    We’ve revisited many coral reef sites that have been monitored regularly in the past continuing the progression of data on the environment there. In addition we have explored new sites, some of which have certainly never been sampled before. On top of this marine work terrestrial surveys and seabird work have been carried out on a number of islands. This ground and sea effort has been conducted in all of the emerged atolls of the territory as well as Blenheim reef, a submerged atoll in the northern reaches of the archipelago.

    The research has been broad ranging and included work investigating coral biodiversity, coral community change over time, coral health, coral trait composition, sea temperature and conditions, sea cucumber population, reef fish biodiversity, Coconut Crab populations on the islands, seabird breeding, and manta satellite tagging. Doubtless plenty of interesting analysis and publication will follow some of which will be posted to this blog to show what results have come from the field time on BIOT Science Expedition 2014.

    Before signing off from the expedition blog until these results are available we must remember the folk that made our work possible. Thanks must go to the BIOT leadership both in the Territory and in the United Kingdom who hosted us directly on location or administratively from afar.

    Our warmest thanks must go to the crew of the BIOT Research Vessel who offered us cheerful support at any time of the day and night creating a working atmosphere that many of the scientists described as one of the most pleasant they had worked in around the world. And the food was incredible, a massive boost on any physically demanding field trip.

    It was an absolute pleasure being on board. All of the science would not have been possible without the crew’s hard work. A big thumbs up to you from all of our expedition participants! 

    Lastly, thanks to all the expedition participants for their hard work and good company throughout. Looking forward to more of the same next year!

  • Stalking mantas and swimming with sharks - BIOT Science Expedition 2014 Day 18

    Stalking mantas and swimming with sharks

    Today was a day for large pelagics. There was not a breath of wind this morning and the sea around the BIOT Research Vessel was flat calm and inviting. Perfect conditions for the wrap up day in the outer islands of the Chagos Archipelago. Visibility underwater was phenomenal making sharks easy to spot and there were a lot of them on the steep reef wall that we dropped in on.

    Turtles, rays and mantas added themselves into the mix while on the shallower reef top the rubble and bedrock offered nooks and crannies for plenty of octopus to peer from with curiosity.

    In these quality surrounds the morning’s data collection went ahead at various dive sites around the reefs of the atoll. But the afternoon offered up a new opportunity as David set himself to deploy some satellite tags.

    “Today we woke up to find that the water was a flat as a pond and the sun was shining brightly. This made for perfect manta tagging conditions. Myself, Jon, Sophie and Pete set off after lunch on the hunt for mantas feeding in the lagoon. Several transects were completed with no sign of a single manta despite a green turtle doing its best manta impression. However, our luck would soon change.  On our final transect we came across a group of 5/6 mantas feeding in the middle of the lagoon. Jon positioned the boat carefully ahead of the group so I could cut them off. The first time I approached the mantas turned on the side exposing their ventral side. Not an ideal location for tagging. I could see the dorsal side on my second attempt but for the manta to make a swift exit as I approached. The third attempt was a far stealthier affair. This time I came at the manta from behind, and undetected, positioned myself above the 2 metre ray and successfully deployed the tag. A bull’s-eye, perfectly placed! And a second successful deployment soon followed. After the second manta was tagged the group had dispersed so we headed back to the ship. It was great to tag two of these ocean giants but we now have an anxious three month wait to get the data back. Where will they go? We will see!”

    Unfortunately we didn’t get any pictures whilst tagging the mantas as we were all focused on the task at hand but we were entertained by a friendly common noddy tern as we motored back to the BIOT Research Vessel. At first he landed on Pete’s hand before trying my head for a perch and then dropping in front of Sophie as shown below.

    As per usual while we were getting underwater Pete was on his way ashore to continue his terrestrial studies. His work in the outer islands on this expedition is done and he offers some insights on his findings below.

    “After surveying eleven of the twelve designated and proposed Important Bird Area (IBA) islands and a number of other (rat-infested) islands, what can be said about the breeding seabirds of the Chagos after this expedition?  First, let us look at the context of the results.  What these scientific research expeditions achieve for bird monitoring is to provide a snap-shot of what breeding is occurring at that time.  In the Chagos they do not provide a definitive figure for the annual breeding populations, as they would in a northern hemisphere environment where there is a defined breeding season and the entire breeding population can be surveyed.  Further, the lack of regular long-term monitoring (including at different times of the year) means that what data is gathered cannot be fully interpreted in a population trend context.  This is because we do not know, for example, how often complete breeding failures as happened this trip with Sooty Tern, actually occur.  With those caveats in mind, a brief summary of the results of the more numerous breeding species follows:

    Sooty Tern:  This species has had a catastrophic breeding season.  This should be the most numerous breeding seabird and over 100,000 breeding pairs is the expected norm on four to six islands.  This year less than 1,000 pairs bred on two islands.  On Parasol in Peros Banhos 26% of chicks examined held ticks and the main colony of approximately 32,000 pairs deserted at the egg-laying stage.  On Middle Brother, the previous survey in 2012 recorded 32,000 breeding pairs.  This year there were less than 500 pairs and these were also tick-infested.  What is not known is, is this a “normal,” periodic phenomena or a one-off event possibly leading to an overall decline in numbers?  Collaboration with colleagues working on this species in the western Indian Ocean may answer this question.

    Red-footed Booby:  This species appears to be holding its own.  The three largest breeding colonies (3,000+) are on Nelson’s and Danger Island and Diego Garcia.  Diego Garcia will not be surveyed on this trip as it takes at least five days to cover all the breeding area.  To further complicate the surveying, the birds in the northern atolls start breeding earlier than those on the southern atolls.  On Peros Banhos and the Solomons breeding was well underway and 95% of nests checked in these atolls held chicks that were between one and two months old.  Further south on Danger Island and the Egmont’s all nest bar one were at the egg-laying stage.  Previous surveys I have undertaken on Diego Garcia tell me that breeding there will not get fully underway until May.  And then, to complicate the assessment further, small numbers of this species breed throughout the year!

    Brown Booby:  This beautiful bird produced a record count of over 700 breeding pairs on North Brother, the majority at the egg-laying stage.  There is one other large colony in the Chagos, on Danger Island.  This colony only held 38 breeding pairs but, these were all at the fledgling stage!  With several recently fledged juveniles in the air around the northern point of the island, it was obvious I had missed the main breeding period.  So, it is difficult to make a true comparison but it appears this species is doing well and may be expanding its breeding range with a nest being found on Ile Longue, Peros Banhos.

    Lesser Noddy:  This species also appears to be sustaining its breeding population in the Chagos but has historically proven problematical to survey due to an erratic breeding season.  Counts throughout the year since 2008 have revealed an annual breeding population in the region of 35,000 – 40,000 pairs centred upon three major colonies on Nelson’s Island, South Brother and Petite Ile Bois Mangue and smaller colonies on many other islands.  This year’s survey has coincided with breeding in these three main colonies and the total recorded has been comfortably above 35,000 pairs.

    Common Noddy:  This species continues to be of grave concern in the Chagos.  In the 1970’s, Nelson’s and Danger Island and Sea Cow held terrestrial breeding populations of 10,000+.  These numbers had declined to the low thousands by 1996 and terrestrial breeding had all but ceased by 2006.  This situation has not changed and the annual breeding population has remained at under 5000 pairs.  Crucially, this species no longer breeds in dense colonies on the ground.  It now breeds in isolation in trees.  Whilst still common, the population is likely to be in decline but has not manifested itself yet due to longevity. 

    Conclusion:  A season of highs and lows.  The take-away point is if we are serious about conserving birds (and other terrestrial organisms) in the Chagos we have to understand their ecology, part of which is their breeding phenology.  This aspiration is still a long way off and can only be achieved by regular surveys throughout the year over a long period of time.  Only by knowing such simple things as when and where a seabird breeds, how often and in what numbers, what on islands is impacting their breeding and most important, what oceanographic events trigger breeding, will we really be able to implement effective conservation management plans.  Sadly, time may be running out for effective conservation measures in the Chagos for Common Noddy and Sooty Terns.”

     

  • Crabs, birds and a profusion of fish - BIOT Science Expedition Day 16 & 17

    Crabs, birds and a profusion of fish

    As we were out in the dark hours pursuing the nocturnal kings of the islands, the impressive coconut crabs, I was nowhere near the internet last night so it is another double up on the blogs today. This overnight effort completed the work we were doing ashore and Pete has a few words on how things have gone.

    “Tired and rain-sodden, a craft came to retrieve the overnight shore party as the day broke.  We had just completed the final night of surveying for Coconut Crabs.  Three very different islands and 75 transect lines later, our nocturnal activities continued to raise more questions than they answered.  One island without rats had a fairly even distribution of adults and juveniles; the small rat-infested island had no adults at all and the large rat-infested island had many very large adults, the majority being males.

    We intend to fully analyse our data and hope to publish a short paper on our findings.  So little is known of this IUCN Red-Listed Data Deficient species in the Chagos that all published information is important as it could assist with management plans to protect and conserve it.  This is particularly pertinent as its range and numbers are declining globally.  Similar to some of the bird species that are thriving in the Chagos, these breeding stocks are of critical importance in the Indian Ocean as they can act as reserves to restock depleted populations elsewhere.  It is hoped our Coconut Crab surveys on this expedition will be the catalyst for further studies of this unique gastropod, the largest in its family.  Watch this space in 2015 for more information.”

    Although night activities on the islands have curtailed sleeping hours a little there has been no let up in the dive programme. So it has been a full couple of days with a busy night in between. The dives during the day have seen us both lagoonside and Oceanside of a couple of islands which have provided a good bit of variation in the environment underwater. There have been a few areas where there have been large die offs of coral which are showing signs of stabilising and in contrast to this areas very rich in coral diversity and health. Over the reef the fish life has been varied and prolific. Some dives provided a wealth of megafauna, large grouper and sharks gathered eyeing us inquisitively, whilst other dives had a profusion of smaller fish schooling around the outcrops of reef.

    An amazing setting for the last two days work, John Turner has penned a few words to share more on his efforts here.

    “While undertaking  long term monitoring of coral reefs, myself and Ronan Roche are also building up a picture of the larger scale structure at each reef site.  Greater structural complexity provided by coral colonies can provide a greater variety of niches for other species, particularly fish which are being assessed by Melita and Heather at the same reef sites.   The video archive being recorded by myself provides a high definition close up view of the coral structure at a scale of a few metres , while a small camera mounted on top of the underwater video camera records a wide angle image every 30 seconds at a scale of tens of metres, dependent on underwater visibility. Ronan records notes to describe reef structure at a scale of up to 100m, and also records some close up photographs at a scale of 50cm to 1m to ‘truth’ the video imagery. 

     Ronan and I will combine our image data and observations to describe the topography and rugosity (roughness) of each reef, and these results will provide an important factor in understanding the structure of fish communities.”

    The dive and work programme has been very busy on this trip and left little time for reflection. There are moments of quiet though when we can just enjoy the richness of the environment and wildlife here. Surfacing from the dive today to find the sky around the dive boats teeming with curious seabirds from the nearby rat free island was such an opportunity. Whilst we sat on safety for the following dive team as they drifted beneath the waves we had the company of energetic boobies and terns as they breezed about on the gentle wind. In our discussions now realization is dawning amongst our group that we are almost at the end of our time here. Better make the most of it and keep busy. There will be time for reflection when we are home, for the moment soak up and discover as much of the great environment of this remote territory as is possible.

  • Sharks and shoals - BIOT Science Expedition 2014 Day 15

    Sharks and shoals

    Today saw us sampling two quite different sites. The first, a steep drop off on the Oceanside of the atoll offered a shoal of baitfish that drew in a host of predators. Tuna, jacks and rainbow runners knifed through the shimmering curtain of tiny fish shoaling about them. All this action distracting us from our work on the reef below, apart from Heather and Melita who were kept busy trying to keep track of the various species taking part in the action.

    The second lagoonside site was teeming with big predators of a different sort. Grey Reef and Silvertip sharks cruised around us while a large gathering of sizeable Coral Trout kept track of us with their goggling eyes. Not the most comfortable of companions to share the reef with while trying to keep your head down and examining the corals below. Frequent glances upward with big eyes to match those of the trout...

    Professionals that they are the expedition crew scribbled down the data they needed and photographed various subjects of interest despite the finned ones swishing about. All of the information they gather needs to be recorded suitably for later use and it is this that really turns the days on expedition into long ones as people work late into the night to process all of the day’s gleanings. Anne has penned a couple of paragraphs to describe this work.

    “For every hour long dive there are many more hours of work, from the preparation of different recording materials to assembling the data collected.  The first stage of this is the recording of all the various measures that have been made, from fish biomass numbers through various coral records to data logger readouts. 

    This is done each evening on the ship, transcribing from underwater slates or prepared sheets of underwater writing paper onto various computer spreadsheets, databases and the like.

    On return to our various home institutions the analyses begin, but that is in the future for us at the moment, now we are concentrating on collecting all the necessary information, from the data needed, to the data that just might be needed as getting out here is so difficult and expensive and we don't want to miss anything out.”

  • Rest Day? BIOT Science Expedition 2014 Day 14

    Rest day? BIOT Science Expedition 2014 Day 13

    24 hours without diving. Opportunity for a rest? Not likely when there is data entry, expedition equipment maintenance and terrestrial work to be done. Let’s not bore you with the former two that every scientist and expeditioner will be familiar with and go straight for the ground based efforts.

    The scene on shore was reminiscent of Jurassic Park with giant beasts pursuing tiny squeaking prey through the tropical undergrowth. On this occasion the tiny squealers were Sooty Tern chicks and our researchers took the part of T-Rex on the prowl as they raced around to gather the small birds for ringing. Pete has penned a few words on the purpose of this effort.

    “Today we woke to gentle rolling and the sound of seabirds overhead, we were anchored off rat-free islands.  On taking my morning tea to the back deck, overhead were some 500 frigate-birds, using the heat from the ship’s stack as a thermal to rise high in to the blue skies.

    It was a rest morning for the divers and the opportunity was taken to take a large team ashore and, hopefully, ring a host of Sooty Tern chicks in this new area.  This is another island cluster where it is believed the Sooty Tern alternate which island they nest on.  Ringing the flightless chicks with a unique serial numbered ring on one island and catching them again as adults, should prove if these birds do indeed switch breeding islands.  With minimum training the marine scientists soon picked up how to handle chicks and record bird-style data. 

    Sadly, the expected Sooty Terns were not on this island in the numbers expected.  There were some young chicks on the island so it was decided, as per the previous island that held terns, we would take a closer look at these chicks.  Our worst fears were met when we found that these chicks were tick-infested too. 

    It appears that the Sooty Tern peak breeding period in the Chagos in 2014 has been catastrophically impacted throughout all atolls by parasitic tick infestations.  Only long-term monitoring and scientific research will reveal if this event happens periodically (likely) or, the Chagos Sooty Terns are in terminal decline (hopefully not likely).” 

    By lunch time our 24 hours out of the water were up and some returned for a beautiful Oceanside dive off the atoll rim. This differed from previous dive sites in having a steady plateau at ten meters that shelved a long way out toward the west before dropping down a steep sandy bank to 20 meters that then shelved off once again and gradually descended to the darkness as a sandy slope. The coral gardens on the uppermost plateau contrasted markedly with the sand. Fortunate for me the scientist I was paired with required a data set just under 10 meters so I explored the gardens with my camera and shot some stills like this pic of a Regal Angelfish.

    The days activities did not end there though. Now anchored alongside a fresh island we went ashore for the dark hours to measure coconut crab numbers again.

    This time there were large adult crabs aplenty to count. On some occasions the scenes of the morning seemed reversed as these giant arthropods turned their fearsome claws on the scientists trying to measure them. Cue the advance of primitive armoured beasts and retreat of squealing scientists. Pleasing to see how healthy the crab populations can be under the right conditions. The Chagos provides just the right combination to be a great haven for these giant characters of the crab world.

     

  • Coconut crabs at night - BIOT Science Expedition 2014 Day 12 & 13

    Coconut crabs at night

    After a bit of sleuthing of satellite imagery a few unexplored coral knolls in the lagoon were selected for diving discovery today. There is a satisfying feeling that accompanies the prospect of getting underwater in a place that has is new. Both of the knolls proved to be in keeping with the condition of the reefs elsewhere in this atoll.

    As we entered the water we were presented with a great diversity of coral and accompanying fish sloping down into the depths. The days research diving routine preceded a different approach to the evening though.

    On this night we had some terrestrial transects planned. Heather will share a little more on what we got up to.

    “Being part of a science expedition to Chagos is a real privilege, spending a night on a tiny uninhabited island in the middle of the Indian Ocean is extraordinary. It seemed only apt for me to get involved with terrestrial ecology with a species that breeds in the ocean – the coconut crab. I’d seen Pete and Jon B returning hot and blistered from the tough work of preparing the transect lines while I spent the day underwater doing fish surveys.

    After a quick turnaround, the ‘island team’ were dropped off as the sun went down on Vache Marine. I’ve heard a lot about this island as it’s the target for a pilot rat eradication programme later this year and as I set up my tent, one of this island’s unwelcome rodents watched on curiously, not showing quite as much caution around humans as I’d have liked!

    Our job for the night was to use a standard survey method to assess the coconut crab population on Vache Marine, providing an important baseline prior to the eradication programme. Before it got dark, the first task was to hack open some coconuts and deploy them as bait along the prepared transect lines.

    Following the patchy weather of the last few days, we were lucky enough to have a stunning starlit night, making the surveys a lot easier and more pleasant. As night fell, armed with a transect tape, notebook and head torches, our approach was to walk 30 metres from the beach towards the centre of the island, recording where we found coconut crabs and documenting relevant details about them. It quickly became apparent that there were very few coconut crabs at all, and those that we did find were juveniles. The piles of crabs on the bait were primarily other hermit crab species and after the 12 prepared transects we’d recorded very few crabs.

    We then did a series of unbaited surveys in a more ‘freestyling’ fashion, with me following Pete into the bush at periodic intervals. Along the way we also documented other key observations – notably the first record of a non-native gecko that’s found in other parts of the archipelago.

    A few hours later, we sat on the beach and discussed the many questions raised by our findings. Where were the adult coconut crabs? Were they being eaten by rats? Were they outcompeted by the other crab species? We hope to start to shed light on these questions through other surveys we’ve planned on two other islands. Having added some field notes, we were ready for sleep. I was very glad of my tent when I was woken very early with something scratching at my head through the fabric – though I didn’t find out whether it was a crab or a rodent! I will be very glad when there are no more rats wreaking havoc on the island and it’s restored for the wildlife that should be there, including native plants, birds and coconut crabs.”

    Greeted by clear skies at sunrise another fine day offered us a comfortable setting to get underwater at a few dive sites we have visited several times over the last decade. On this occasion the reef shelved out gently until a precipitous cliff that dropped cleanly to darkness below with open blue water stretching out into the ocean ahead. Great stretching gorgonian fans dotted the vertical reef with clouds of fish hovering over the abyss. On the surface in between dives one of our crew was accompanied by an inquisitive turtle that swam alongside her for several minutes. Perhaps this turtle had never encountered a human before. Great to be in a place where for a change people are a novelty rather than the wildlife!

  • Coral gardens – BIOT Science Expedition 2014 Day 11

    Coral gardens

     

    Last night the clouds cleared their curtain away revealing the stars and so today dawned with blue skies and sunshine. A welcome change and just the right conditions to enjoy a couple of superb sites in the lagoon close to our overnight spot. Whereas Oceanside reefs can often be battered by storms from the open sea which break up larger coral formations, those corals in the lagoons can develop with unconstrained grandeur.

    Today we broke the surface to find diverse gardens of thriving coral stretching in each direction awaiting our exploration. On completion of dives our scientists returned to the surface with smiling faces and phrases rich with superlatives for the environment below.

    Although the condition of these reefs is largely due to their remoteness from human civilization, they are not completely removed from humanities influence. There is much debate over global warming and temperature is one of the things that is being measured here in the Chagos Archipelago. Anne has a few words on this work.

    “When 90% of corals were killed in the Indian Ocean in 1998 due to a huge warming event, we were dismayed to see that the Chagos reefs had been hit just as badly as the rest.  But the following few years showed the corals returning and surveying  the amount of new, live, coral and comparing that figure to coral cover data that we had from the late 1970s, showed that Chagos, unlike most of the rest of the Indian Ocean, was recovering, and recovering remarkably well.

    As a result of this we have been regularly monitoring the seawater temperature (in case of another warming event), the coral cover and the recruitment of new, juvenile, corals on the Chagos reefs.  Data loggers record the seawater temperature every two hours and can store the accumulated data - the batteries can last for three to four years.  Every expedition we download the data from the loggers and replace them, but the trick is finding them again each time!  We have GPS coordinates for each one, and these are now remarkably accurate, but it still sometimes takes a good bit of searching to locate one small length of rebar with a six inch piece of plastic pipe cable tied to it.  Often it is because the rebar is the only straight thing on the reef that gives it away.  The logger is in the plastic pipe to stop it being bitten by parrotfish.

    There have been other small warming events in recent years but thankfully nothing like the episode in 1998.  Chagos reefs have recovered better than almost anywhere else in the Indian Ocean, with only a very few small areas having recovered as well.  The pattern of recruitment is interesting, with parallels with terrestrial vegetation - first come the weeds then comes the forest.  The huge Acropora tables seem to be the weeds - very beautiful weeds certainly - and we are now seeing large numbers of them die off.  Is this natural senescence or something else?

    The numbers of juvenile corals we are seeing is vast.  Last year they were tiny spots seen through a hand lens, this year they are all bigger and much more obvious.  Dead Acropora tables are a favourite base for them to settle on and it remains to be seen what will happen to these juveniles when the Acropora tables break up and erode.  The tables may possibly (hopefully) become cemented onto the reef in some cases and allow the young corals to continue to grow.”

    As we were examining the world beneath the waves Pete continued his terrestrial efforts with our intrepid expedition Doctor in tow.

    “The weather was calm enough this morning for Jon Bailey and me to head to the island where it is hoped a rat eradication attempt will be carried out later this year.  We intended to “kill several birds with one stone” (excuse the pun!) today.  The most pressing job was to identify and prepare transect lines to survey this island for Coconut Crabs.  This would be extremely useful data to gather for three reasons.  The most important being it will facilitate a before and after rat eradication analysis of their numbers, along with bird, turtle, hermit crab and vegetation information gathered already.  This is vital information in order to assess the impact of removing invasive introduced predators from an oceanic island ecosystem.  The intent is also to compare this island’s Coconut Crab density and demographics with a rat-free island we hope to visit later in the expedition and also with a control site that is not harvested on Diego Garcia.

    The second bird to fall was to map and establish the grid system that requires cutting in to the island’s vegetation in order to disperse rat poison later this year.  To achieve at least in part this goal, the Coconut Crab transects were doubled up as grid-lines.  The actual days work involved recording way points and physically marking key points, following compass bearings, using measuring wheels and the cutting of 300m of transect lines, not to mention swimming ashore with iron marking posts!.  This was hot, hand-blistering work but a fun and essential day to the long-term ecological improvement of these islands.”

  • You can't order the weather...BIOT Science Expedition Day 10

    You can’t order the weather

    Climatic shenanigans continued today. The squalls of yesterday developed into a consistent wail of wind into the morning. We managed to launch for the day’s planned dive in the lee of an obliging island but this ingenuity on our part only seemed to convince the storm that it hadn’t tried hard enough. On surfacing we were battered by the tempests less than gentle gusts and barged up and down by the jumping waves it had roused from the sea. After an entertaining recovery to the BIOT Research Vessel we conceded to the weather and spent the afternoon catching up on the growing pile of data and samples that needed processing from the last 10 days activities.

    On the dive the beautifully calm clear waters below restored balance to the morning’s conditions above. Well worth risking the weather for the pleasing coralline vista sloping gently from the island to the depths. Shoals of triggerfish had their home amongst the whip corals in the deeper darker edges of the slope.

    A deep cave revealed a host of lobster jostling away from the torchlight that disturbed the darkness of their retreat. In the shallows closer to the revealing light filtering down despite the turmoil above, large grouper paraded in between mounds of coral while groups of pastel painted parrotfish hurried about scraping their fodder from the stony seabed. Needless to say such an idyllic setting was still not sufficient to tempt us back into the storm for the afternoon. Tomorrow is another day. Until then I’ll let Melita explain a little more of her research.

    “This is the first time I’ve surveyed reef fish in Chagos which makes it very exciting for me to be part of this expedition. I have long wanted to be here as I come from Kenya and so working in Chagos is highly relevant to the work I’m doing in the western Indian Ocean. I’ve been surveying fish in Tanzania, Mozambique, Comoros and Madagascar measuring the diversity of species on reefs and also their population abundance. I’m hoping that Chagos will provide me with a baseline for fish population abundance for the region because the reefs here have not had intense fishing like elsewhere. However Chagos did have a specific commercial line fishery for some reef species until the area was turned into a marine park in 2010. So it might be early days before we see populations of those species return to unfished populations levels.

    The “fish team” do three things on a dive covering around 200-300m along the reef: we make a complete species inventory for 19 families, using photographs as a back up for identifying the tricky species; we do a 10 minute “long swim” to count big and elusive species like sharks, tunas, trevally, groupers and Napoleon wrasse, and then we do 50x 5m transects counting the numbers and sizes of a broad range of species that range from snappers to surgeon fish. One of the most exciting things I’ve seen so far is how big the coral trout grouper are – we are seeing 1 metre long males; this is the maximum size they reach! I’ve never seen this before and I’ve worked on this species in the Indo-Pacific since the 1980s.”

  • Squalling Away - BIOT Science Expedition 2014 Day 9

    Squalling away

    Squalls happened today. Frequently and tropically. Swollen seas, gusty winds and torrential downpours were our companions for the day’s activities. Luckily diving involves getting wet anyway so the latter was par for the course but the former two had effect on our plans. Of the two dive parties venturing out this morning the first had to turn back from their Oceanside target site and select an alternative in the shelter of the lagoon. The second dive party negotiated some dominating seas to find their calmer waters on the far Oceanside of an island to the wind. While those beneath explored the watery beauty around the reef, those on safety watch above could see the approaching squalls and watch the gradual arrival of tumultuous curtains of rain before an overcast break between downpours allowed a little drying for soaked bodies.

    Despite the less than ideal conditions a full days diving and terrestrial work went ahead. Temperature loggers were recovered and replaced, fish, coral health, coral biodiversity and other surveys were the order of the day, all contributing to the build up of scientific knowledge of the Archipelago. In some respects the weather worked in our favour as we explored new dive sites within the lagoon that proved to be stunning in the richness and health of their corals, and biodiversity and abundance of fish life.

    Whilst we all were getting wet diving Pete continued his terrestrial forays.

    “Today another two islands were visited, both proposed as IBAs due to their breeding seabirds.  The tide was on the rise when we reached the first and we could not navigate the boat over the coral reef fringe surrounding the island.  This meant we had to jump over the side of the boat swim-surf over the reef fringe and then walk the remaining distance to the shore; a bracing start to a day of monitoring!

    The first of the islands has held over 20,000 breeding pairs of Sooty Tern in previous years though none were present today.  The island did hold approximately 1600 pairs of Lesser Noddy and the usual numbers of breeding Red-footed Booby, Common Noddy and Common White-tern.  By the time we finished our survey the tide was high enough for the boat to collect us from shore and deliver us to the nearby sister island.  This island has spectacular stands of Pisonia grandis trees and these are home to the largest number of breeding Lesser Noddy in the Chagos.  Despite some of the veteran trees being blown down in the recent storms, the Lesser Noddy were breeding in all stands and, a new sight for me, in stands of smaller Neisospermia (Ochrasia) oppositifolia on the island too.  This extension of breeding range on the island produced the highest count of breeding Lesser Noddy for this island, some 14,000 breeding pairs.  Whilst the storms have damaged trees and chicks of tree-nesting seabirds have been lost by being blown out of the nests, other species benefit.  On the forest floor large numbers of Coenibita hermit crabs were waiting for their next feed, including the giant among this family, the Coconut Crab.  More to follow on this unique omnivore tomorrow, if the expedition plan is unaffected by the weather!”

    Jon, our expedition doctor, who accompanied Pete on his island explorations during the day arrived back at the boat early in the afternoon. This allowed him the time to turn his healing skills to the air compressors which fill our scuba tanks. Critical to achieving our underwater aims these need to be kept in tip top condition so the engine surgery kit of spanners, spares and nuts and bolts came out with a few cans of oil and perhaps a little dose of profanity. Duly sworn into wellbeing the compressors did their duty and we’re set for diving in the morning. Fingers crossed we won’t be getting quite so sodden and windswept while not submerged.

     

  • Back to diving...BIOT Science Expedition Day 8

    Back to diving...

    Sharks ate the whole expedition crew...I’m the only survivor and typing this with my remaining left hand. April Fool’s day and after a week the expedition crew are sufficiently settled for a unique community sense of humour to have developed. Banter is up and after a day out from diving yesterday everyone was full of energy and raring to get underwater again. All are more comfortable in the routine after a week on board and are happy that their work is going well. Today I followed John beneath the surface and gleaned a little more on what he is getting up to.

    “One of the most important functions of the Chagos Marine Protected Area is that it serves as a reference site to measure change in the absence of direct impacts from human populations.  However long term changes can be difficult to assess, especially if those scientists measuring the changes also change over the years! By recording what the reefs look using video, it is possible to compare sites across years.

    Each day, Ronan Roche and I are selecting coral reef sites which I first visited in 2006. Our aim is to dive a similar profile and record on video what the reef looks like today, and to be able to compare these observations with those made in 2006. The video records are being carefully filed so that they can be compared in future years as well.

    Coral cover on Chagos reefs has been assessed for more than 20 years, providing a valuable long term record of change over time in response to major environmental variables, such as  warming events and bleaching induced mortality. Although photographs of many reef communities exist, these have been taken selectively and do not really present an objective record of the state of the reefs. High resolution video recorded across wide tracts of reef can show the state of that reef. A video archive of the structure of communities allows documentation of change and the identification of features that may not previously have been recorded in counts because their significance was not evident at that time.  It also enables new generations of scientists to revisit reefs visually, and the video can be reanalysed to identify changes and to address questions of resilience and response.

    10 minute sequences of video are being recorded over 5 m depth intervals on both seaward and lagoon sites, and these will be compared with video recorded in 2006.   We are already noticing that many of the shallow table corals that grew rapidly at shallow depths following the 1997 mortalities, and were very prevalent in 2006 and now being replaced by a more diverse range of species, which can be expected to increase in biomass in subsequent years unless affected by further impacts.  Many table corals appear to have died and are being dislodged by water movement and are falling down the  reef slope.  Last year, we saw that corals below about 15m depth in Salomon lagoon had died, probably due to warm, dense water at depth, and low circulation due to the reefs that surround most of the atoll. We have been delighted to see recovery of many of these corals in just 12 months.   Some site displayed damage from plagues of the Crown of Thornes starfish, and we are now eager to revisit these sites to see whether they have recovered too.   Such fast recovery shows that the coral reefs of Chagos are very resilient, and this is almost certainly because there are no direct impacts from humans."

    The terrestrial work is also continuing and today measured impact of a different kind. Pete can elaborate from their trip ashore today.

    “Today a Chagos bird mystery was solved and a pleasant surprise was had.  The pleasant surprise was finding a new breeding island for Brown Booby.  This species does not tolerate human disturbance at its breeding islands and the new location is a testimony to the control of access to certain islands in the Chagos.  The mystery that was solved was why Sooty Terns desert breeding islands periodically in the Chagos.

    My morning was spent assisting Liz with sea cucumber transects.  The return deal was Liz was to assist me in the afternoon monitoring two islands that are IUCN categorised Important Bird Areas.  On approaching the first of the IBAs it was immediately apparent there was no mass breeding episode happening on the island.  The same thing happened when I visited this island in 2009.  I suspected then that avian parasitic ticks were the cause of the breeding failure as I found a small number of chicks with ticks attached.

    We moved on to the second island on which I had been told that in January of this year there were over 10000 breeding pairs present.  Alarm bells rang when on approaching the island there were no “Wideawakes” calling over the island.  As we walked in to what should have been the breeding area, instead of the cacophony normally associated with a Sooty Tern colony, all that was heard was the food-begging call of a small number of chicks.  We decided to investigate.  On walking around we noticed huge numbers of abandoned eggs, our calculations estimated 32000 pairs had tried to breed.  Then we noticed some small chicks which we captured for examination.  They had ticks.  On further investigation we found that 26% of the chicks had ticks, some carrying as many as 20.  Similar to what has been experienced in the Seychelles, Chagos Sooty Tern was experiencing breeding failure through excessive parasitic tick loads.

    Although awful to witness, the fact that it was ticks causing Sooty Tern to desert breeding islands in the Chagos offered opportunities.  The first was to assist other researchers who are working on gaining a better understanding of the impact and distribution of avian ticks on seabirds in the Indian Ocean.  We collected a large sample (thanks Liz!) that will eventually find their way to colleagues in the Seychelles who specialise in this niche.  The second opportunity was to review how we categorise what islands are ecologically “important.”  Had these IBAs been assessed this year their true value would have been missed.  In 2011 I suggested in press that most of the individual islands designated as IBAs should be classified as IBA in clusters on account that Sooty Terns did not nest on them all annually.  This argument was expanded upon in a scientific publication edited by Professor Charles Sheppard.  Today’s findings add more weight to the IBA cluster proposal, and give credible evidence why Sooty Tern do not nest on all breeding islands every year.”

     

     

     

     

  • Day out from diving - BIOT Science Expedition Day 7

    Day out from diving

    As much as we would like to continue diving all the way through this expedition, safe practice suggests a breather once a week. Today was that day. Instead of diving we ventured ashore with Pete to gain an insight into his work with the bird populations here in BIOT. He describes our experiences below…

    “Today we woke to a new experience for those of the science team who have not conducted research in the Chagos before.  To date we have only anchored by islands that were rat-infested, this morning we woke anchored off a rat-free island.  The contrast was immediate.  As dawn broke streams of Lesser and Common Noddy departed the island for feeding grounds.  Above them Red-footed Booby were heading purposefully to their deep water feeding areas, alongside were smaller numbers of Brown Booby heading for shallower waters to feed.  Frigatebirds glided over looking as though they were inspecting the ship whilst the occasional Wedge-tailed Shearwater lived up to its name as it headed out to sea. 

    It was a rest day for the divers and they were to head ashore later in the day to feel some terra firma for the first time since leaving Diego Garcia.  First, Jon Bailey and I were to spend the morning ashore continuing the long-term monitoring of the breeding seabirds on this IUCN recognised Important Bird Area (IBA).  Concurrently Jon Schleyer and Sophie were filming on the island.

    There are three senses that are immediately bombarded when coming ashore on a rat-free island when seabirds are breeding, aural, visual and olfactory.  We landed next to a breeding colony of Lesser Noddy, some 11,000 pairs.  The smell of guano was keen in the air, the hungry calling of chicks and the chattering of parent birds was a cacophony of sound and there were birds literally all around us.  After this grand start we walked the circumference of the island stopping along route to measure the density of the other key breeding species, frigatebirds and Brown and Red-footed Booby.  It was difficult not to be distracted by the superb photo opportunities of the other wildlife on the island; the endemic sub-species of Argus Meadow butterfly and hawkmoth were both showing well today.

    The afternoon was a well earned break on land for the marine scientists.  Whilst a “terrestrial-science guided tour” by me was the intent of the afternoon, it was soon apparent that the marine scientists were not only keen to hear about the island environment, they were also keen to further their skills as photographers.  Some of the results illustrate today’s blog.”

    Spending time enjoying the rich terrestrial life was not the only activity, these rest days are important for the participating scientists to catch up on their data entry and catch up physically after 6 days of a busy diving and working routine. In between these ‘resting’ moments meals through the day were rich with discussion on what had been observed over the last week and plotting for the next window of diving opportunities coming on the morrow. One week down and two to go!

  • Exploring Fresh Territory

    Exploring fresh territory BIOT Science Expedition Day 6

    It is a rare thing these days to be able to explore a place that perhaps no one else has ever seen first hand. The reef we visited today is a place where, on entering the water on scuba, you may well be the first person to see that seabed ever before. In the early hours of the morning we cruised to a fully submerged atoll that reaches to within meters of the surface but never breaks it. It is sufficiently remote that people rarely visit, and even more rarely get beneath the surface.

    One of our party dived here in 1979, and David, who has just joined us from the Bertarelli Foundation's research vessel, ventured underwater on this reef in the last few days whilst undertaking his shark research. Although I’ve been to the territory many times I have never had the opportunity to dive this reef and was very excited at the prospect. I was not disappointed. The corals were beautiful, receding into the distance in branched, mounded and encrusting growths with thousands upon thousands of varied fish flitting, shoaling and cruising overhead. A storm of colour pleasing the eye. Giants floated through, a turtle stopping to occasionally rest amongst the coral garden, Napoleon Wrasse regally parading overhead, nurse shark hurrying along and grey reef sharks eyeing everything keenly while cruising by.

    In this distracting environment Courtney showed a lot of resolve to keep her head down (most of the time...) to survey the corals. I’ll let her elaborate a little on what was keeping her busy beneath the hive of life in these waters.

    “The scope and magnitude of the global coral reef crisis is daunting for most, especially those of us who understand all too well how complex the threats can be. So how do we bring this seemingly unapproachable issue to a level at which local management action can be effective while still addressing the synergistic nature of global and local threats? While I will be the first to admit that I chose a slightly morbid career path, I’m fascinated with how disease shapes and reshapes coral reefs. Disease, much like other ecological processes, is a part of all wildlife populations and nature’s way of weeding out the weaker individuals.  However, the steady increase in coral disease during the last 40 years, together with the daunting list of other stressors, have drastically reshaped the structure and function of reef ecosystems and are now considered one of the major contributors to global coral reef degradation. As a disease ecologist what’s especially concerning is that disease levels can be exacerbated by environmental stress. With atmospheric CO2 predicted to rise as high as 900 ppm by the end of the 21st century and predicted climate-induced increases in disease, it is crucial to understand how reefs will respond to climate change in the absence of other anthropogenic stressors (such as pollution). This is particularly challenging given the lack of ‘baseline’ data for most regions, but is possible to address using datasets with large geographic coverage across a wide range of environmental conditions. The British Indian Ocean Territory is one of the few places on the planet that we can study the effects of climate change on coral disease in the absence of other stressors.

    During the 2104 BIOT cruise, I am helping develop BIOT’s first coral disease monitoring program by building on initial surveys conducted in 2006, identifying major conditions affecting coral health, describing the patterns in coral health and disease, and identifying disease hot spots. After a lot of deliberation, trial and error and several doses of reality, I’ve found a plan that works for this remote region where we have limited days and bottom time to cover a very large area. To describe disease patterns across the Chagos Archipelago, I'm surveying as many sites as possible. At each site I roll out transect tapes, record all types of coral disease, count and identify all corals, and essentially spend 60-70 minutes with my face buried in the reef. When I have a few minutes to spare, I’m roving the reef looking for other diseases. It looks as though we’ll be spending several days in at least one region, so if all goes according to plan, I will also track several diseased colonies over time using photographs to determine how rapidly these diseases are killing the coral tissue.”

    Pete has also continued his work with birds and this atoll without islands presents some different opportunities for his work.

    “After yesterday’s deluge it was good to wake to see the storm had passed over and that we had moved location and are now out at sea.  As dawn was breaking I found a juvenile Bridled Tern on deck, it had probably sought refuge from the rain in the night in the shelter provided by the ship.  Bridled Tern is not a common species in the Chagos so I took this as a good omen for the day to come.

    Today’s survey location was one of the submerged banks of the Chagos and this gave another opportunity to show Louis a different seabird census technique – monitoring seabirds at sea.  We use a standardised period and method of scanning the ocean from the bridge wing, recording all birds seen in a specified arc.  Being at sea and next to a submerged bank allowed me to further another part of my research, how seabirds use the Chagos MPA for foraging and feeding.  Every opportunity has been taken on previous expeditions to record seabirds at sea, noting the species, number, behaviour and any associations with marine mammals or fish throughout the different marine habitats the MPA provides.  Data is now revealing that there are feeding hot-spots in the MPA that are used regularly by certain species of seabirds and these are mostly associated with sea mounts, banks and shelves.  These submarine features provide the required habitat and resources for concentrations of fish and these concentrations attract hungry seabirds.

    Again, knowing how organisms actually use the different marine habitats, in what numbers and whether there are feeding associations is extremely useful information for protection and conservation within the MPA.  For the internationally important breeding seabirds of the Chagos it is vital that not only are they provided with a safe, introduced predator-free island to breed on, they require their food source protecting too.  Some seabirds rely on predatory fish and marine mammals to drive small fish to the surface where they can then predate them – this means for the seabirds to prosper, the underwater predators (and their ecosystems) require protecting and conserving too.

    Overfishing and the by-catch from certain fishing practices have negatively impacted seabirds globally.  In this No Take Marine Protected Area science has proven that, excluding some top predatory fish such as sharks that have declined through illegal poaching, fish stocks are very healthy.  It is likely that as food is abundant it is a lack of successful breeding that is limiting population increase in ground nesting seabirds.  If more islands provided safe breeding conditions (i.e. free of introduced rats and cats) then the numbers of breeding seabirds could increase.  There is a wonderful opportunity here in the Chagos to buck the global trend of decreasing numbers of seabirds by investing in real terms a small amount of money to eradicate introduced predators from throughout the archipelago.  I look forward to tomorrow when we visit a rat-free island to show Louis and the marine scientists what an introduced predator-free island looks, sounds and smells like, where thousands of seabirds should be present!”

     

  • Pouring tropical rain - BIOT Science Expedition Day 4

    Pouring tropical rain

    Today rain poured from the sky. Not the half hearted wettening that many of us are familiar with in Europe but rather the humid heart of the tropics poured out in a torrent from the heavens. We may have got more than a little damp during the days activities. When we awoke the curtain of rain was so dense that there was no prospect of diving or indeed any other excursion from the boat. Lucky for us the clouds were kind and parted for us to depart and get underwater.

    Some headed out to conduct sea cucumber surveys, check autonomous reef monitoring systems or recover long term temperature loggers, while the remainder headed to the northernmost point of the atoll for an Oceanside dive. Hundreds of spinner dolphin greeted us as we motored out of the lagoon, careening along in formation around our bows and jumping in unison alongside us, almost within arms reach. It was a shame to break away from this mutual entertainment and stop to dive. But the sights underwater were just as delightful, if slightly less mobile. Once again beautiful vistas of corals with clouds of colourful fish festooned all around. The god of tides and weather played funny again though and a roaring current picked up tearing at the divers trying to hold position over the reef. Getting back into the boat holding on for dear life with one hand while trying to unclip gear without it being swept away was a task and a half. The remaining dives for the day would be within the lagoon. A far calmer enterprise. I did see Doug hard at work before the current picked up and flicked off a few photographs of him doing his thing whilst randoming across the reef. He has written a few words to explain what he is getting up to out here in BIOT...

    “I am studying the coral diversity and coral diseases of Chagos.  Corals are particularly important on coral reefs, of course, because they are a primary builder of the reefs, and also because they provide habitat for many other species, particularly fish and small animals that live among coral branches.  There are many fewer species of coral on most reefs than species of fishes, however, most individual coral species are harder to identify than fish.  All studies of corals need to be able to identify the corals that are being studied, and corals are an important part of the biodiversity of coral reefs and the reef ecosystem.  Many corals can be identified alive, underwater, but it takes lots of experience to learn to identify corals, learning to identify one species at a time.  Further, different corals are present in different parts of the world, on different reefs, and in different zones of reefs, and even what we think are the same species can look different in different areas.  The most secure identifications of corals are done with skeletons, because the actual taxonomy is based on the skeletons.  So some collecting of samples of problematic or interesting species is helpful, and even collecting a sample to confirm identifications of all species strengthens a study.

         In my study of coral species in Chagos, I take a slate with me on dives, with names of about 450 coral species on it, and check off the species as I find them.  After each dive, I make estimates of the abundance of each species I found on a 1-5 scale.  I like to survey from deep to shallow on a dive, since some species only live deep and others only live shallow.  So looking both deep and shallow increases the number I can find.  Further, I do a roving search dive, looking for more coral species.  I start deep and work my way up into shallow water, since that is the safest way to do a dive.  As I go, I photograph corals, trying to get a photograph of each species of coral in the expedition, and also trying to get photos of all the particularly interesting looking corals that I may not immediately be able to identify.  Later I will work with various books to identify as many corals in photos as I can.  I also will collect a few samples occasionally to use them to help me to try to work out what they are.  I have this type of data from many dive sites from a variety of areas of the Indian and Pacific Oceans to compare my data with.  This data compliments data from quadrats or video which gives more quantitative accuracy but usually doesn’t have corals identified to species and doesn’t find as many species.

         Coral diseases are a threat to coral reefs.  Diseases have killed the majority of two of the most common corals in the Caribbean, and more and more diseases are being found in the Caribbean.  So far, diseases have been less of a problem in the Indo-Pacific and fewer diseases have been recognized in the Indo-Pacific.  However, diseases may be on the increase in the Indo-Pacific and they aren’t studied nearly well enough to know.  So I am photographing what appear to be diseases as I find them, and if the opportunity presents I am counting diseased colonies and healthy colonies as I survey coral species.  My disease work will compliment that of Courtney, since she is primarily doing transects at one depth.”

    So on completion of our sopping rainy day there is one last important thing to mention. Our number has been augmented. David Curnick, who has been doing shark research on board the research vessel provided by the Bertarelli Foundation, has crossdecked from that vessel to ours. Now that the Bertarelli Foundation's vessel has completed her research voyage she is departing but David is remaining with us to assist with coral reef data collection for the remainder of our trip. Welcome aboard...

     

  • Diving the dropoff and working with seabirds...BIOT Science 2014 Day 3

    Diving the drop off and working with seabirds

    We’re settling into a routine on board now so deploying for the morning dive was somewhat slicker than yesterday’s attempt. Despite a couple of boats being out the water for running repairs and the distraction of a playful pod of dolphins en route we still plunged in for the days first dive well ahead of schedule. We could hear the dolphins whistles throughout our submersion but they’re really wary of divers and only ventured close enough to be visible on a couple of occasions. An invisible choir for our listening pleasure whilst working the reefs.

    The site we chose was a busy one, rich with corals and clouds of fish. From previous dives here we know that the place is prone to strong currents and this is evident in the abundance of anemones. They like to have the tentacles wafted by the moving water. With the anemones come the inevitable anemonefish. And special for this site, a large number of these beautiful little anemone symbionts are the endemic Chagos Anemonefish. These are not the only fish that provided a spectacle while we worked, a small snapper proved to be very tame and kept flitting from dive pair to dive pair for company. More to come on the marine side of things tomorrow...for today I thought I’d ask Pete to fill you in on the birding programme in a little more detail so here are a few words from him...

    “Today presented the opportunity for me to introduce Loius to a different island in the Chagos and to show him some techniques for monitoring breeding seabirds.  An early start saw us dropped on the beach.  Fortunately there was no requirement to swim ashore.  We then walked the circumference of the island counting the number of nesting Red-footed Booby using a standard technique called Apparently Occupied Nests (AONs).  I am looking at trying to confirm the peak breeding period for this species in the Chagos (they nest throughout the calendar year) so I take AON a stage further and try to ascertain at what stage of the breeding cycle the birds are at, e.g. eggs, small chicks, large chick, etc.  This is possible for many nests that are low down on trees, but does normally involve wading out in to the sea to look back at the shoreline!  This expedition’s survey data will be combined with counts I have made at other times of the year to and unravel the breeding phenology of this species and, whether it is linked to any oceanographic events.

    Loius witnessed first-hand some of the dangers and challenges facing seabirds, not only in the Chagos but throughout the world.  The first example was of a small chick that had fallen from its nest on to the beach and was being devoured by crabs.  Whilst sad and grisly this is a natural process.  The distressing example of the challenges facing seabirds worldwide was of an adult Red-footed Booby hanging upside-down, dead in a tree.  Despite there being no fishing in the Chagos Marine Protected Area, this bird had become tangled in monofilament fishing line, carried it back to its nesting/roosting tree where it became snagged and died, likely through exhaustion from trying to free itself.

    Despite the challenges to the breeding seabirds, they are faring well in the Chagos.  Today’s example of the importance of the Chagos for seabirds comes from the Red-footed Booby.  Throughout the Indian Ocean breeding colonies of this species have declined or totally disappeared.  Historically this was the case in the Chagos too but things are changing.  In the first major survey of the breeding seabirds in 1996 the island Loius and I looked around today held no breeding Red-footed Booby.  Today, thanks to some surviving magnificent Takamaka trees on the shoreline that provide a suitable nesting platform, this island had a minimum of 169 breeding pairs.  Globally there are very few oceanic islands, atolls or archipelagos that can boast of increasing or recently increased breeding seabird numbers; the British Indian Ocean Territory can.

    The Chagos Archipelago is a sanctuary for breeding seabirds in an ocean and world where seabirds are generally not faring well.  Everything should be done to protect this breeding stock and where possible, facilitate an environment in which they can increase breeding numbers.  With sympathetic shoreline habitat management that would increase native trees that seabirds prefer to breed in e.g. Takamaka, Pisonia and Barringtonia, coupled with an invasive mammal eradication programme, the British Indian Ocean Territory could be the Indian Ocean reservoir of seabirds to repopulate protected but impoverished islands elsewhere.  Ecological improvement of oceanic islands is not a green dream; it is occurring worldwide and has already been achieved in other UK Overseas Territories.  The time must surely be near where the will and the finances will become available to allow the ecologically devastated islands of this wonderful archipelago to be restored to something of their former glory.”

     

  • Getting to work...BIOT Science 2014 Day 2

    Getting to work...

    The crew of the BIOT Science Expedition 2014 gathered on the deck of the BIOT Research Vessel.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Today we got to work. As if that isn’t what we’ve been doing for the last few days already but now we are getting to the tasks that we have all been working towards. The science and data collection. I’ve been dive buddying Elizabeth throughout the day and here are a few words from her.

    “Today I have been taking photos of the coral communities around the northern atolls of the Chagos Archipelago. I take photos of the reef and also record the exact location and depth at which each photo is taken. Since GPS devices cannot receive signals underwater, we attach it to a flotation device which we drag along and then later match up to photos using specialized software. Later, back in the UK I will analyze these photos, determining what coral species are present in each image and what type of environmental conditions exist at the particular location at which they are located. I will then take a rather unusual approach to understanding how the reef ‘functions’ by translating the coral species composition into life-history trait composition. These traits describe among other things coral morphology (i.e. shape, size), reproductive behaviour, and aggression towards neighbouring corals. By focusing on traits we can gain insight into not just the diversity of species present (i.e. taxonomy) but also what they ‘doing’ (i.e. their function).”

    Although the majority of scientists on the expedition are focussed on marine work there is a party that have been doing terrestrial science and that is rattling along at pace too. Pete and Louis have ventured ashore with Jon B to start the bird work. So perhaps airborne could be a better descriptor than terrestrial but here are a few words from Pete on the bird programme.

    “The ornithological programme is varied and challenging on this year’s scientific expedition.  The long-term monitoring of the internationally important breeding seabird populations, especially of the Important Bird Areas (IBAs) will occur as far as the expedition programme allows.  This is extremely important information as an indicator of the health of the Marine Protected Area (MPA) and the data set now stretches back to 1996.  In addition to the repeat surveys of the islands, as part of his PhD research, I am trialling GPS tracking devices on Red-footed Booby in order to try and identify key feeding and foraging areas for seabirds in the MPA.  Today we fitted two Red-footed Booby with devices and it is hoped these birds will start to reveal the potential Marine Important Bird Areas within the overall MPA.  In addition I am starting a long-term ringing and tracking project on Sooty Tern in the Chagos Archipelago.  Sooty Tern is a key species in the designation of IBA status for islands in the MPA.  It is thought that Sooty Tern move breeding islands periodically, probably due to excessive parasitism by ticks.  We will be attempting to ring as many Sooty Tern chicks as possible (if breeding) in order to assess natal site fidelity and to ascertain if they do indeed “swap” breeding islands.  This is important information from a conservation perspective and if proved, will bolster the argument I have made in press for making clusters of islands IBAs, rather than individual islands.  I will also be collecting ticks on chicks for identification as part of a wider Indian Ocean project on tick associations with Sooty Tern.”

    So the science expedition has now truly taken off. More tales of our exploration and discoveries to follow!

  • Getting the gear on...

    Getting the gear on (14 03 26)   

    There are few things that will motivate a marine scientist to do dull tasks better than the prospect of an amazing dive. That prospect was a distant one when everyone arrived bleary eyed at the air terminal in Diego Garcia shortly before midnight yesterday. But we hustled them straight into a vehicle, or perhaps hustled their equipment onto a vehicle and squeezed them in somewhere between the piles of luggage they brought with them. Researchers are not renowned for packing lightly. Fortunately it was a short transit to the jetty where our vessel for the expedition was waiting.

    We duly threw their gear onto the BIOT research boat which predictably resulted in the scientists scuttling on board in pursuit of their precious gizzits. All participants safely tempted on board the skipper cast off and we were away across dark waters. Bunks were sought and occupied with purpose. A good night’s rest would not only be a good soothe for a few days build up of jetlag but also set people up for what would be a full day of action starting in the morning.

    Elizabeth readying her underwater cameraInevitably the day started with an interminable health and safety brief detailing the various ways which we should avoid maiming ourselves over the coming weeks. The side benefit of this process was that everyone in a fog of dulled senses agreed to help set up the entire dive infrastructure on board in two and a half hours in order to get a refresher dive in by mid-afternoon (that’s right, drills and briefs took up the entire morning). Their plight in being so deceived was soon overcome by the prospect of getting underwater in one of the most pristine and prolific coral reef environments on the planet. Not a shabby spot for a shake-out dive before the work starts in earnest on the morrow.

    Now motivated, the tortoise pace of the mornings activities was replaced by a fervour of dive hungry preparation. Compressors set up, boats prepped, pony tanks fitted, fuel mixed, cylinders filled and boats in the water by 3 pm. Not bad from a standing start. Concurrent to this Pete and his shore party of avian enthusiasts readied themselves to get ashore on Ile Mapou. A reconnaissance trip for subtly accosting seabirds to fit radio tags on the following day.

    All the anticipation was not unfounded. Once deployed on the water in our dive dinghies the Salomon Atoll served up a rich late afternoon of treats for us as we tested our dive kit. A pod of dolphins gambled in the afternoon sun as we exited the lagoon. Huge grouper gaped at us as we dropped in at our selected dive site off the northern edge of Ile Anglaise. A lazily large manta appeared effortlessly out of the haze of dusk lit water before dissipating into a curtain of late afternoon sunrays slicing down through the water. A curious grey reef shark ushered us from the water back onto our dive boat and sent us, a happily dived up crew, back on our way to the research vessel.

    The evening threw up a final treat for the day. The opportunity to share the adventure of getting out here through a maze of logistical hurdles and administrative difficulty to the first viewings of the Chagos Archipelago’s environmental treasures with the crew of our sister research vessel out here provided by the Bertarelli Foundation. Whilst our vessel is a working boat turned to science. Their’s is a luxury motor yacht turned to the same task at the behest of the boat’s owner, a benefactor of the BIOT MPA. It was fantastic to share our first experiences of this amazing place with another science crew who are just drawing to a close with their work out here. Our work will compliment theirs as they have placed the gear to monitor sharks and large pelagics while we pursue the secrets of the reefs and smaller reef fishes and seabirds above. And so the pursuit of further knowledge of the natural environment in BIOT progresses...now to bed. More tomorrow!

  • The promise of things to come

    Professors pumping up raft with footpumps

    Seeing Professors kicking away at footpumps to fill inflatable boats with air in preparation for a science expedition is an entertaining way to start things off. A bit like an academics aerobics symposium in a boat warehouse. This was the illustrious start point to this year’s trip when all the planning and discussions coalesce to action on the ground – in this case researchers blowing hot air into inflatable tubes by a repetitive foot thrust to the floor. On such small beginnings rest grand ambitions and the Chagos Archipelago is a suitable hunting ground for those.

     

     

     

     

     

     

     

     

     

    As previous voyages through the outer islands have shown through their results, the natural environment here sets benchmarks globally. Whilst clumping your foot on a wheezing canvas bellows may seem a strange way to get there it is a necessary chore in the pursuit of such exploration results here. In this remote place without making thorough preparation access to the secrets of the reefs of the outer atolls would be unattainable. So pushing your foot to the floor to pressurize an inflatable boat takes on a new significance when it means that you will be well set to cast off a mooring line in a few days time and dive on some of the healthiest reefs with the richest marine life in the world. An outcome any biologist hankers after in their happy daydreams.

     

    The advance party setting themselves to the preparatory chores have gained a taste of the riches that await as we have managed to get out for some local data collection dives in between the various tasks on our agenda. The reef surveys in the waters here have already offered up a host of spectacular and fascinating sights. From the smallest animals, like the colourful Sexy Shrimp (Thor anoinensis), to the largest with the sighting of several silvertip sharks alongside the reef drop off. 

     

     

     

     

     

     

     

     

     

     

     

    Much more of the same is soon to come. So we will redouble our efforts to ready all the stores and equipment in anticipation of the arrival of the rest of the science expedition participants early next week. We have more boats to assemble, a laboratory to furnish, dive equipment to test and fuel and food to replenish. This beneath a tropical sky brightly lighting the beautiful turquoise waters of BIOT beneath which a treasure trove of marine environmental wealth awaits our discovery. An enchantingly tempting view to keep motivation up whilst stamping our feet down on those footpumps!

2014 BIOT Expedition

 An international group of scientists visiting the British Indian Ocean Territory Marine Protected Area in March and April on an expedition to explore and research the rich natural environment of the Chagos Archipelago.

Chagos 2014 Expedition Biographies

March 24th – April 15th 2014

 

Prof. Charles Sheppard:

Professor Charles Sheppard has been working for several decades on the marine ecology of tropical seas.  He focuses on the corals, their abundance and identity, and changes that have occurred over the years in key environmental parameters. Because ocean warming and climate change are so important, he relates community changes to climate change, especially to warming pulses that damage reefs.  He is editor of a very large marine environmental science journal, and has written and edited numerous books and papers on this subject including on the remarkable Chagos archipelago, but focusing as well on tropical areas from the Caribbean to Australia.  Regarding Chagos, for 10 years was BIOT Commissioner’s scientific advisor, before giving up that position and becoming Chair of the Chagos Conservation Trust.

In 2014, Charles Sheppard will focus attention again on the status of the corals which build the Chagos Archipelago.  Factors such as coral cover, juvenile coral density and mortality of older colonies will be investigated in order to assess the ‘health’ of the reefs.  Arrays of underwater temperature data recorders will also be retrieved, data downloaded, and replaced.  In addition he will assist in recording of factors such as poaching and of the health of previously poached marine species.  We hope also to investigate further the huge seagrass beds that were recently discovered far from the islands, and also will re-examine the area where a crown-of-thorns outbreak on the Great Chagos Bank 2 years ago killed almost all corals on a portion of reef, to determine recovery potential in the archipelago.    With colleagues, he has found that the natural resilience of Chagos reefs was relatively fast compared with areas that suffer stresses from most human induced kinds of exploitation, such as sewage, over-fishing and shoreline disturbances.

Anne Sheppard: Research Associate, School of Life Sciences, University of Warwick.

Anne has been a coral reef ecologist on several research expeditions to the Chagos Archipelago since her first 9 month long trip in 1978, when she was the first woman ever to have dived there.  Her main focus of research is coral taxonomy, monitoring reef health and the recovery of reefs after human impacts.  Working with her husband Charles, they have dived together for research purposes (and pleasure!) on many reefs around the world.  She has also taken many land and underwater photographs of the archipelago which have used to promote conservation both of Chagos and coral reefs in general.  She is a trustee of the Chagos Conservation Trust and is also editor of CCT’s journal Chagos News.

On this expedition she will be continuing the monitoring of reef recovery in Chagos by measuring coral cover and will be starting a new project looking to see if the makeup of the coral community has changed even though the cover has returned to the levels it was pre the 1990s die offs due to warming.

Pete Carr: Avian biologist

Pete Carr has had a long association with the Chagos having led three ornithological expeditions to Diego Garcia and then lived and worked on Diego Garcia for four years between 2008-2012.  During that time he visited every island of the Chagos and found some 25 new bird species for the Territory.  He was instrumental in establishing which islands became Important Bird Areas, published the book Birds of the British Indian Ocean Territory and has had articles in journals on the birds of Chagos, including British Birds.  Pete has recently completed a Masters by Research degree with Warwick University, the thesis being on Red-footed Booby and factors impacting their selection of islands in the Chagos for breeding and, the implications for future island management plans.

Elizabeth Widman:

Originally a native of northern Sweden, I completed my higher education in the United States, Ireland and England. In 2013 I was awarded my PhD in Systems Biology from the University of Warwick, where I am currently lecturing as a visiting researcher. I am also developing the ‘Chagos Resource Portal’ (funded by the Chagos Conservation Trust), which will compile data from research conducted in Chagos over the past 40 years into an online relational database. The database will be spatially projected using GIS and serve as a platform for communication between researchers, the public, and decision-makers.

Whilst I do spend much time with my computer, as a former professional basketball player, I greatly enjoy the physical nature of fieldwork and have to date logged over 100 scientific dives. Prior to my PhD studies I worked as a freshwater ecologist in the United States as both as a consultant and also within a long-term monitoring program with the Michigan Department of Environmental Quality.

Planned research:

A fundamental shift is taking place in community ecology from species to traits as the basic unit of measurement (traits being the morphological, physiological, behavioral, and phenological life history characteristics of species). This shift in focus allows for new exciting lines of enquiry into ecosystem functioning (McGill, 2006). On this expedition I aim to collect a series of photo-quadrats on reefs across the archipelago using the same methodology employed on 66 reefs across Southwest Madagascar (Widman, 2012). These photos will be used to determine coral species composition and then translated into coral trait composition. Applying an array of progressive trait-based analytical techniques (i.e. Widman, 2012; Pavoine et al, 2011; Mason, 2005), to the acquired dataset I aim to probe fundamental questions about Chagos coral communities such as: 1) How functionally interchangeable are species (i.e. system redundancy)? 2) What are the basic functional properties of the reef systems (i.e. functional redundancy, richness, evenness, and divergence)? 3) How does Chagos compare to more heavily impacted regions (i.e. Madagascar)? 4) What is the geographic distribution of functional diversity; are their functional diversity hotspots?

In addition, I will be contributing to the long-term monitoring efforts of holothurian (sea cucumber) populations across the Chagos Archipelago, closely following the data collection protocol of previous expeditions (i.e. Price et al., 2013).

Douglas Fenner:

Doug received his B.A. at Reed College in Portland, Oregon, and his Ph.D. from the University of Pennsylvania in Philadelphia.  Doug began diving and doing transects on islands in the Caribbean, and described reefs at Cozumel, Mexico, Roatan, Honduras, Cayman Brac, and St. Lucia for the first time.  He then started working on corals in Hawaii which eventually lead to his field guidebook to the corals of Hawaii.  After that he worked with organizations in the Philippines for two years, surveying reefs and learning to identify coral species.  Then he worked for Charlie Veron at the Australian Institute of Marine Science for six years on an electronic key to corals.  Most recently, he worked as a coral reef monitoring ecologist in American Samoa, doing the benthic monitoring for nine years.  Doug has surveyed coral species diversity on reefs across the Pacific and Indian Oceans.

Melita Samoilys:

Melita has worked on coral reef research and management in the Indian and Pacific Oceans and in Sudan’s Red Sea since the early 1980s. Her particular areas of interest and experience are in fisheries, reproductive biology of groupers particularly spawning aggregations, coral reef fish diversity, marine protected areas, community – based coastal management and conservation and alternative livelihoods. She is co-Director of Coastal Oceans Research and Development – Indian Ocean (CORDIO) based in Mombasa, Kenya.  CORDIO East Africa is a research organisation focused on conservation of marine and coastal ecosystems in the Western Indian Ocean. CORDIO specialises in generating knowledge to find solutions that benefit both ecosystems and people. Melita’s Doctorate is from James Cook University, where she is Adjunct Associate Professor in the Dept of Marine Biology. She is a member of several international advisory bodies including three IUCN Species Specialist Groups (Groupers and Wrasses; Snappers Seabream and Grunts; Sharks); the Institute for Water Environment & Health, United Nations University and the Marine Stewardship Council (MSC) Developing World Working Group.

Melita will be investigating diversity and population abundance of reef fishes in the lagoons at Chagos. The objectives of the surveys are:

i) to measure the diversity of reef fishes in Chagos lagoons using a standardised method used in the Western Indian Ocean based on a pre-defined list of 19 families;

ii) to measure abundance and biomass of a broad cross section of the fish community (using a WIO standardised method) to determine the densities and biomass of key trophic groups considered important in coral reef resilience;

iii) to estimate the abundance and biomass of groupers as taxa that are generally highly vulnerable to overfishing and consequently depleted and threatened in most coral reef regions. Chagos may represent some of the most pristine populations of coral reef groupers in the world.               

I have recently quantified coral reef fish diversity and population abundance in Madagascar, Comoros, Mozambique and Tanzania, a core region representing the highest biodiversity in the WIO. The Chagos survey provides a unique opportunity to collect directly comparable data to my WIO dataset and should provide the missing baseline as Chagos reefs arguably represent the least damaged and least fished reefs in the Indian Ocean.

Dr. Heather Koldewey:

Heather started working for the Zoological Society of London (ZSL) in 1997, initially as a research scientist, then as curator of the ZSL London Zoo Aquarium and now as Head of Global Conservation Programmes. Heather specialises in marine and freshwater conservation and as co-founder of Project Seahorse www.projectseahorse.org has been involved in establishing 34 community-managed marine protected areas in the Philippines. She is also involved in marine and freshwater conservation projects in Mozambique, Cameroon and the Pitcairn Islands. She was a member of the February 2012 expedition to Chagos and is one of the lead researchers on the 3-year Darwin Initiative project to strengthen the Chagos Marine Protected Area by providing scientific knowledge for effective management. Heather is an Adjunct Professor at the Fisheries Centre, University of British Columbia, Canada and a research associate at University College London and the University of Exeter. She is a Board member of the Chagos Conservation Trust and Shark Trust, as well as representing ZSL on a number of national and international conservation committees including the Chagos Environment Network and the British Indian Ocean Territory Science Advisory Group.

As expedition leader, Heather will work to ensure the smooth and safe implementation of all scientific activities in BIOT. She will be working with Melita Samoilys investigating diversity and population abundance of reef fishes in the lagoons of Chagos.

Dr John Turner:

John Turner is a Senior Lecturer in Marine Biology with expertise in temperate and tropical marine environments and the interaction between human impacts and the aquatic environment. He has over 25 years of experience in a wide range of projects involving Coastal Habitat Survey, Marine Protected Areas (MPA), Environmental Impact Assessment (EIA), and Integrated Coastal Zone (ICZM) in a range of countries and contexts. He has undertaken large scale biological surveys for UNDP-GEF Projects on Sustainable use of Biodiversity of Socotra Archipelago, and Coastal Ecosystems of the Andaman Islands, and EIAs for major industrial developments (eg. LNG terminal, Oman; effluents, Mauritius). John's research advances techniques for integrating spatial biodiversity data in marine systems for the purpose of assessment of state, for establishing Marine Protected Areas (MPAs), and for long-term monitoring and investigating change. He is a field biologist, experienced in undertaking manipulative experiments, survey and monitoring on coasts and underwater. Current interests focus on the establishment of MPAs (Cayman Islands, Chagos, Tonga); shark and ray ecology and behaviour (Philippines, Belize); Reef resilience to human impacts and climate change (Cayman & Indian Ocean islands); and Coastal Zone Management and Sustainable Development (East African coast).  John has visited the Chagos three times (2006, 2008and 2013) and is an Executive Member of the Chagos Conservation Trust.  John currently leads three DEFRA Darwin Initiative projects: Darwin Initiative to strengthen World’s largest MPA, Chagos 2012-2015; Darwin Initiative to enhance an established marine protected area system, Cayman Islands 2010-2013, Darwin Initiative Assuring Engagement in Cayman’s Enhanced Marine Protected Area System 2013-2014.

Coral cover on Chagos reefs has been assessed for greater than 20 years, providing a valuable long term record of change over time in response to major environmental variables, such as  warming events and bleaching induced mortality.  Although photographs of many reef communities exist, what has been lacking is a video archive of the structure of communities which would allow documentation of change and the identification of features that may not previously have been recorded in counts because their significance was not evident at that time.  A video archive enables new generations of scientists to revisit reefs visually, and the video can be reanalysed to identify changes and to address questions of resilience and response.   10 minute sequences of video were recorded over 5 m depth ranges (5-10, 10-15, 15-20, 20-25m depth) at seaward and lagoon sites on all atolls in 2006, and these are being repeated during the 2013 and 2014 Darwin Initiative expeditions.  Initial analyses indicate that primary framework species that grew rapidly at shallow depths following the 1997 mortalities, are now being replaced by more diverse secondary framework species, which can be expected to increase in biomass in subsequent years unless affected by further impacts. There are already indications of new events occurring, such as mortality of lagoon corals below 15 m depth in Salomon lagoon; and loss of banching Acropora on lagoon reefs of Eagle Island and Danger Island due to Crown of Thorns starfish outbreaks. 

Jon Slayer:

Jon’s childhood playground was Sea World in Durban, South Africa, where his father is a marine biologist. His first job was assisting with dolphins, seals and penguins at uShaka Marine World and also participating in field trips to survey the coral reefs of Sodwana Bay. His working career has remained adventurous, as an outdoor activities training instructor in a game reserve in South Africa, white water safety kayaker on grade 5 rapids of the Zambezi River and as a Commissioned Officer in the Royal Marine Commandos. He served for 8 years including operations in Afghanistan, Northern Ireland and Iraq, also spending a year in the British Headquarters on Diego Garcia. There he apprehended poachers and commanded British Operation Patrols around the British Indian Ocean Territory including escorting the science expedition of 2006. Since 2008 he has qualified as a commercial scuba diver in order to focus on filming life beneath the surface. His award nominated films have supported several conservation campaigns and have featured in television documentaries. In Belize he has founded a branch of the marine conservation charity Blue Ventures that monitors and researches the remote Bacalar Chico area of the Belize Barrier Reef. He also works as a Security Team Leader protecting vessels transiting the High Risk Piracy Area in the Northern Indian Ocean.

Dr. Jon Bailey:

Dr. Jon Bailey will be joining us on his second expedition as on board doctor and head of medical logistics. Jon is an Academic Clinical Fellow in Emergency Medicine at Oxford University, John Radcliffe and Milton Keynes Hospitals in England, UK and has experience at the Diving Diseases Research Centre in Plymouth, UK. He is also a diving instructor for both PADI and BSAC.

Louis Elyse:

Louis Elyse currently works for British Airways in the welcome lounge at Manchester airport and graduated from the Connect Chagos Environment Training Course in October 2013, going on to present his experience and great enthusiasm for learning at the Chagos Conservation Trust’s 20:20 Conference the following month. Louis’ parents come from Chagos originally and he gained his hard-won place as the March 2014 Chagos expedition’s Chagossian trainee after a competitive recruitment process, where he shone at interview.

Louis will be the first in his family to visit Chagos since his parents, but for Louis this opportunity means not only to see the homeland of his parents but also an opportunity to be part of an amazing scientific expedition and pass on his experiences to his children. It is a dream come true to get this chance. Louis will be gaining a taster of all the research going on during the expedition, with a particular focus on monitoring of coconut crabs and sea cucumber surveys and hopes to gain many news skills and knowledge with the accompanying researchers.

Dr. Courtney Couch:

Courtney is a postdoctoral fellow at the Hawai‘i Institute of Marine Biology at the University of Hawai‘i at Manōa and recently moved to Hawai‘i after completing her Ph.D. in the Department of Ecology and Evolutionary Biology at Cornell University, advised by Prof. Drew Harvell. Courtney’s research has aimed to understand how ecological processes and environmental change govern host-pathogen interactions and coral disease dynamics. The primary goals of her postdoctoral research are to develop coral health and disease monitoring programs for a number of Big Ocean sites (such as BIOT), address local environmental drivers of coral disease through targeted research in the Main Hawaiian Islands, and build capacity and facilitate communication between marine resource managers and scientists to improve reef resilience planning.

 

Outbreaks of coral disease, acting synergistically with other stressors, have drastically reshaped the structure and function of reef ecosystems, even in remote reefs. During the 2014 BIOT cruise, Courtney aims to augment the first coral disease assessment conducted in 2006 by describing the patterns in coral health and disease, identifying major conditions affecting coral health and identifying disease hot spots. During these surveys, she will be documenting coral disease as well as other biological interactions such as algal overgrowth, predation, sedimentation, etc. While BIOT has historically low levels of coral disease, developing standardized monitoring allows us to target and manage regions at risk facing future environmental change.

Dr. Ronan Roche:

I am interested in studying how natural systems respond to anthropogenic alteration, using a multi-disciplinary approach, focusing on coral reef ecosystems and their long-term resilience and diversity. I graduated in Biological Sciences from the University of Edinburgh in 2000. I carried out research in 2002 as part of my MSc in Tropical Coastal Management at the University of Newcastle in Trindad and Tobago. I then worked for several years in Coastal Zone Management and Fisheries topics at the Essex Estuaries Initiative in Colchester, England. I then was awarded an IGERT fellowship to study at the University of Rhode Island, where I completed the MMA (Master of Marine Affairs) program focusing on Marine Law and Policy in 2007. My PhD thesis was entitled “A multi-proxy reconstruction of mid-Holocene environmental conditions at a nearshore Great Barrier Reef site: King Reef, Northern Queensland.” This project was collaboration between Manchester Metropolitan University, The Natural History Museum, London, and James Cook University, Australia. I am currently working at the Center for Applied Marine Sciences at Bangor University, UK.

Research Plan:

I will be carrying out two strands of research during 2014: 1) collecting reef structure data to complement video surveys, and 2) obtaining bite rate data from several parrotfish species.

Reef structure data on rugosity and slope provides information on the context of video coral reef surveys, allowing correct interpretation of the video footage obtained on the expedition. Acropora species are one of the most abundant branching species on many of the reefs around the Chagos archipelago, and provide a refuge for reef fish. Broadscale assessment of the proportion of dead Acropora corals can be used as an indication of reef health, providing a complementary visual assessment to video surveys. This variable can provide information on impacts such as storm damage, crown-of-thorns starfish feeding, and coral bleaching events.

The net calcium carbonate accretion/erosion state of reefs worldwide is an issue of increasing importance, as evidence shows that reefs in important locations are now in net erosional status. Parrotfish are corallivorous, and so form an important part of the calcium carbonate cycle on reefs, by consuming and excreting coral skeletal material. To calculate the volume of coral skeletal material removed, information on parrotfish abundance and bite rate frequency must be collected. An international team of scientists visiting the British Indian Ocean Territory Marine Protected Area in March and April of 2014 on a research expedition to further knowledge of the rich natural environment there.