ReportofOfficialVisittoBIOT,

April-May2014

ChiefScienceAdvisor,BIOT

Government

Dr Mark Spalding

Chief Scientific Advisor to the

British Indian Ocean Territory Administration

Department of Zoology,

University of Cambridge,

Downing Street, CB2 3EJ,

UK

2

Contents

Trip itinerary ........................................................................................................................................... 3

Introduction ............................................................................................................................................ 4

Key Action Points ................................................................................................................................ 4

Public works ............................................................................................................................................ 9

Freshwater .......................................................................................................................................... 9

Wastewater treatment ..................................................................................................................... 10

Waste and recycling .......................................................................................................................... 11

Pollution in the lagoon ...................................................................................................................... 13

Energy supply and generation .......................................................................................................... 13

Coastal engineering .......................................................................................................................... 13

Imported aggregates for coastal engineering ............................................................................... 15

Marine and Fishing ................................................................................................................................ 16

Monitoring of legal fishing ................................................................................................................ 16

Boat-based fishing from DG .......................................................................................................... 16

Shore fisheries ............................................................................................................................... 16

Yacht fisheries ............................................................................................................................... 16

Surveillance and capture................................................................................................................... 17

Shark human interactions ................................................................................................................. 18

Biodiversity Conservation ..................................................................................................................... 20

Habitat Restoration ........................................................................................................................... 20

Invasives ............................................................................................................................................ 21

Rat Eradication .................................................................................................................................. 21

Public engagement ........................................................................................................................... 21

Boats in northern atolls .................................................................................................................... 22

Waste ............................................................................................................................................ 22

Anchors ......................................................................................................................................... 23

Science and observations...................................................................................................................... 25

Facilities ............................................................................................................................................ 25

Coastal erosion.................................................................................................................................. 25

Fishing impact ................................................................................................................................... 26

Mangroves ........................................................................................................................................ 26

Reefs.................................................................................................................................................. 28

Coral condition and disease .............................................................................................................. 28

Citizen science and conservation ...................................................................................................... 30

Expanding the baseline ..................................................................................................................... 30

Closing comments ................................................................................................................................. 31

Acknowledgements ............................................................................................................................... 32

References cited ............................................................................................................................... 32

3

Trip itinerary

29 April

Travel. Flight with XO

30 April

BritRep meetings

Swim test and mission briefing for trip to outer

islands

US Commanding Officer

PWD Public Works Department staff.

Visits:

Water treatment facility

Coastal revetment work

Quarantine area for coastal revetment stone

Fuel loading bay

Nuclear submarine dock

Fuel pipelines

Drive along E and N shore of W DG new

pipeline

1 May

Visit with BritRep

Dive store

Waste disposal unit

Turtle Cove

Firing Range (British) and adjacent coast

(turtle nesting monitoring site)

Native tree restoration sites

Plantation and Graveyard

Sharks Cove

Metal recycling

Sewage ponds

Plant Nursery

Fishing marina

2 May

W Great Chagos Bank

Eagle Island old settlement, mangrove and

W shore

Dive off W shore

Dive off N Brother

Middle Brother circumnav

3 May

Peros Banhos

Dive of W end Ile de Coin

Ile Vache Marine brief snorkel and circumnav

Ile de Coin settlement

Moresby Island mangroves

4 May

Salomon and N Great Chagos Bank

Dive of S Ile Anglaise

Dive in anchoring area nr Boddam

Ile Boddam settlement

Snorkel N coast Nelson

Nelson circumnavigate

5 May

Visits with XO to E arm of Diego Garcia

Turtle Cove

Restoration site Minni Minni

Barton Point

Snorkel lagoon mouth Barton Point

Beach visits on lagoon and ocean side

Evening dinner and debrief with XO, and BritRep

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Introduction

The following detailed account covers my first visit as Chief Science Advisor to the Government of

the British Indian Ocean Territory in April-May, 2014. The overall aim of this visit was in some ways

focused on familiarisation with the Territory, including Diego Garcia and the northern atolls. In the

process of this visit I was able to meet key personnel and to visit much of the infrastructure around

DG, as well as to visit a number of islands and reefs across the Great Chagos Bank, Peros Banhos and

Salomon Atolls.

Clearly it is not possible for one person to be expert in all aspects of environmental issues ranging

from biodiversity protection to restoration to waste treatment and munitions disposal. To this end

my remit was rather to observe and absorb. During this process I took extensive notes (and

photographs). I was able to undertake some further research into key questions during and after the

trip, and have also benefitted from some feedback from key personnel, which has helped to cut

down the number of questions raised.

The structure of the report breaks into four broad sections, which are somewhat pragmatic and

overlapping, but help to draw the information together in a more meaningful flow:

Public Works focuses on aspects of infrastructure and utilities on Diego Garcia activities

associated with the human habitation which have the potential to have a significant impact

on the natural environment

Marine and fishing focuses entirely on the range of ongoing fishing activities both around

Diego Garcia and the entire territory and on the efforts to manage these.

Biodiversity conservation focuses on efforts to restore biodiversity, or reduce impacts

through targeted management interventions.

Science includes the broad scope of ongoing research and research needs in Chagos,

including research needed for support of management areas above, but also critical baseline

work to describe Chagos and better understand its importance, role and settings.

Throughout the body of this report I highlight a number of issues which would merit further thought,

discussion or action. These same comments have been more briefly summarised in the Key Action

Points below.

Key Action Points

PUBLIC WORKS

Freshwater

We should take stock of operations and look at future plans for the new water treatment plant

including the deepwater waste disposal, any further plans for tree-felling around wells, estimates of

waste, chemical constituency of that waste, and volumes of waste.

Wastewater treatment

The treated effluent released onto the reef could be having an impact, it may be minimal, however it

evidence is needed. On future visits it would perhaps be useful to visit the adjacent beach area and

even (at low tide) walk out to the actual outfall, but such observations are insufficient to understand

any impacts on the adjacent reef.

There should be some water quality sampling at surface and across a depth profile around the

outfalls and adjacent reef areas so the imprint of this treated waste water discharge can be more

accurately described. It would further be valuable to assess ecological impacts through diving or

video surveys.

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Waste and recycling

It may be valuable to investigate the best methods for disposal of large volumes of illegally caught

fish. Are there concerns about this waste, either in terms of volume, leachate or indeed human

health?

Pollution in the lagoon

The findings of the recent water quality assessment studies are eagerly anticipated, but it would also

be valuable to get an understanding of the regular, ongoing water quality testing work and its

findings.

It would be of interest to know if the water quality studies would be sufficient to detect any

influence of leachates from the old (unlined) waste disposal site.

The recent observation of an algal bloom in Diego Garcia points to a potential human health hazard

as well as a threat to marine life. It would be valuable to know more about any other such events

and to develop a reporting mechanism.

Energy supply and generation

Fuel pumping from supply vessels to the land (or other such transfer of toxic or polluting materials in

the lagoon) should continue to be prohibited during high winds or waves. Suppliers are under

contract and clearly under pressure to transfer to tight time-schedules, so it would be advisable to

formalise current best practise.

The large trees/branches overgrowing the fuel pipelines from the POL Pier to the POL Farm should

cut back to avoid risk of damage to pipelines

Coastal engineering

It would be useful to establish how the sedimentation threat from ongoing coastal engineering was

assessed, how effectively the simple measures (working at low tide and stopping work if large

sediment plumes are seen) are being applied and what reasoning was used in assuming further

measures such as sediment skirts were not considered necessary.

There may be value in requesting an independent expert review of the Moffatt and Nichols

proposals for coastal engineering.

It would further be useful to know if there have been any impact studies of sedimentation from

dredging to maintain deepwater harbours and channels, and to find out about what use is made of

siltation avoidance measures such as siltation skirts.

Advisory documentation should be developed for staff and customs responsible for inspecting

aggregates being imported into Diego Garcia for coastal engineering. These should explain the very

high costs of any potential plant or animal invasion and describe the process for conducting

thorough customs inspection prior to and during offloading.

MARINE AND FISHERIES

Fishing

Better reporting of the full recreational fishery around DG is clearly needed, particularly of the

shore-based fishery, but there could also be value in investigating any whether fishing from large

vessels at anchor is taking place, which has been suggested by some observers.

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A detailed description and summary of the information from the DG and yacht based fisheries return

forms should be obtained. We need to consider how to improve returns on the shore (and possibly

yacht) fisheries.

There would be great value in commissioning a new creel survey to assess these fisheries.

There may be some value in providing improved information to reduce risks of shark-human

interactions, and amendments to management, including, for example, possibly separating of

swimming areas from fish-landing areas.

Surveillance and capture

The Fisheries Patrol Vessel (FPV) may already be having a valuable impact on the illegal demersal

fishing, although it is difficult to quantify this success in terms of the proportion of IUU vessels that

are captured, or the deterrent value. There is a far greater challenge to impact possible IUU tuna

catch. For both fisheries there is a need to try and ascertain the levels of illegal fisheries irrespective

of capture.

There could be value in encouraging greater dialogue and collaboration between the various parts of

the BIOT Administration specifically MRAG and the BritRep/BIOT team on-island to enable further

co-ordination of surveillance.

For the longer term it would be valuable to have a rational discussion with all players on vessel and

surveillance needs, science support and possible options. There are clearly different opinions, but

also challenging budgetary constraints. An initial workshop could help to kick-start this process

BIODIVERSITY CONSERVATION

Habitat Restoration

There is a need to review existing information on the native vegetation restoration efforts, to

understand overall policy, species planted, area covered, techniques and proposals for follow-up.

This should be used to develop advice on future efforts.

There is a possibility of engaging existing ground-staff and/or volunteers to extend this work.

Current grounds management in this area is somewhat ad hoc, so such guidelines could yield

significant benefits at little to no additional costs.

There may also be a need for a field based review of these projects, which would enable a more

detailed understanding of progress, including successes and failures, and the costs and benefits of

the different techniques and approaches that have been attempted to date.

Invasives

There would be value in developing a list of pest species for Chagos and DG, which might provide a

target for managers in developing pest control beyond that of ironwood, rats, cats and chickens.

Public engagement

Increasing public interest in the natural environment around Chagos could lead to greater respect

for the natural environment, but also to other benefits in terms of human health and reduced waste

and energy consumption. There is a need for more direct communication and education, including

more signage, but more especially more active communications through the radio/TV. Visiting

scientists should be encouraged to give presentations.

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Boats in northern atolls

Some messaging would be of considerable benefit in the northern islands. Clearer and more forceful

signage regarding regulations are needed to encourage correct behaviour, but by making this

educational and informative it might help engender responsibility. Signage should be seen as an

infrequent but ongoing cost as signs will fade, become outdated or simply look old and be ignored.

The immigration and customs visit could also be used to remind yachts of the rules, encourage them

to return the fisheries forms and of course to keep an eye out for any evidence of rule breaking.

Concerns remain about the impact of anchors on the seabed in Salomon Lagoon. It would be

valuable to obtain a more detailed understanding of the distribution of important benthic habitats,

and perhaps to undertake a (necessarily more sparse) survey of seabed features in Peros Banhos in

order to ascertain the relative importance of anchorage sites. The observations from Salomon also

underscore the importance of fixed moorings.

There would also be some value in detailing the exact GPS locations for the current set of sites used

for anchoring by the FPV to be passed on to future vessels and further to restrict anchoring to these

or a similar restricted set of locations to avoid wide damage.

SCIENCE AND OBSERVATIONS

Coastal erosion

There is an urgent need to develop a robust picture of natural coastal dynamics both around Diego

Garcia and the northern atolls. This should include reliable long-term studies, led by experts in

coastal geomorphology, and setting baselines for an ongoing assessment, which will be of value both

for coastal planning in Diego Garcia and in ongoing discussions about resettlement.

Fishing impact

Although subsistence fishing from the FPV is permitted during operations, there would be some

benefit in providing guidance and limiting the spatial extent of fishing from the FPV. The primary aim

of such an approach would be to curtail any future expansion, but also to signal the importance of

no-take in Chagos and to ensure that some locations are truly without any fishing impact. Closing all

fishing from FPV would probably be counterproductive.

Mangroves

It is not clear that any urgent management intervention is needed for the mangroves, but ongoing

scientific observation and perhaps more detailed mapping and description would be valuable.

Corals and disease

Detailed reports on disease are expected shortly from the most recent science expedition and

should be given close attention.

Citizen science and conservation

A summary of the contribution of Diego Garcia based personnel to conservation and science, would

provide a powerful message, and could be enhanced with a review of the range and potential for

future citizen science and conservation work, which might serve to encourage ongoing and new

efforts and would aid the transfer of skills and knowledge to new personnel.

Scientific baselines

There remains is a need to understand environmental settings around Chagos more broadly in terms

of geography and discipline (ecology, oceanography, geomorphology), through continued expansion

of basic descriptive science, particularly in areas where there has been little or no observation to

date (both in terms of geographic location and key disciplines).

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A science plan already exists and work is underway to develop a conservation and management

plan. While there is overlap between these, it is appropriate that they should be maintained as

distinct outputs. Critical to such planning tools is a vision of need and prioritisation, particularly to

guide the necessarily limited budgets of the BIOT Administration, but also to help in the assessment

of proposals for other visiting scientists and the potential engagement of new partners in

conservation work.

There is also a strong need for a centralised data store for environmental information on Chagos,

including findings from the science, from the fisheries patrol, and from non-sensitive environmental

studies around DG by military and contractual visitors. As much as possible should be made open

access, with data-sharing protocols to be determined and agreed to as an a priori requirement for all

those working in Chagos.

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Public works

Freshwater

Freshwater has been extracted from the freshwater lens in two locations. Visit to N site, where

water is pumped from around 100 wells distributed through adjacent forest areas. They have a

number of test wells where they check levels and if there are signs of falling levels nearby wells are

closed off with extraction redistributed across the remainder. Current supply is easily sufficient for

resident population, but need to have readiness for visiting.

The southern area of water supply, near to the airport is now being connected with a new pipeline

to a new treatment plant under construction. The S site was closed due to its proximity to two major

oil spill sites although not directly adjacent, there was a fear that water abstraction might lead to

lateral flow of polluted water into this area. Apparently there is some slight risk of hydrocarbon

contamination of this water, so this is being tested. Prior to the spills this water was considered

better quality than the northern site, with lower organic content and conductivity. This has been

attributed to the grass cover over the S wells, rather than forest over the N wells.

Raw water from these lenses is generally high in organic content and so is treated with chlorine, but

this leads to high levels of trihalomethanes, making it non-potable. Potable water is currently

purified with nanofiltration.

An effort is underway to improve water quality with a requirement to make all water potable

throughout base. This centres around a $27 million project underway to bring in nanofiltration, and

to upgrade supply tanks and pipe as necessary. The re-activated southern lens will also be connected

to the new water treatment facility.

Building work on the new water processing plant (left), and the pipeline connecting to the southern water supply (right)

Two prior reports from the previous CSA have discussed these issues. There were concerns that

water abstraction was high and potentially threatening to vegetation, some wells had had to be

abandoned. There were concerns over plans for removing large numbers of trees, apparently to

reduce evapotranspiration, but there may be some confusion here. The only trees being felled were

for the building work around the new water purification plant. Further concerns were raised about

10

the inefficiency of nanofiltration or reverse osmosis this is not only linked to the increased demand

of water needed to cover that waste, but also the disposal of waste. The wastewater is still fresh, but

with relatively high concentrations of the undesirable organic and mineral compounds. I was told the

current plan for this wastewater is pumping to deep storage at 180ft, rather than pumping into

wastewater treatment. It is not clear where this storage will take place.

We should take stock of operations and look at future plans for the new water treatment plant

including the deepwater waste disposal, any further plans for tree-felling around wells, estimates

of waste, chemical constituency of that waste, and volumes of waste.

Wastewater treatment

Wastewater receives secondary treatment in two treatment plants. The key treatment is in lined,

open, ponds with mechanical aeration, and benefitting from UV irradiation from sunlight. Treated

wastewater is monitored to ensure compliance to DGFGS discharge standards. Chlorine is added

prior to release. Wastewater is then pumped via pipelines to be released at the reef crest in two

locations. There appears to be no ongoing monitoring of the impact of these releases and no

ongoing water quality testing.

Sludge is removed during major repairs of liners (approximately once every 10-15 years). Sludge

can be dried using a sludge drying bed or in the sewage lagoon once the wastewater is removed.

Sample from dried sludge is collected and sent off-island for hazardous waste characterization. If

found hazardous, sludge is shipped off-island for treatment and disposal. If found non-hazardous,

sludge is buried in the landfill or use as compost materials with green waste (e.g. tree trimmings and

grass cuttings). (Diego Garcia Environmental Officer pers comm, 1 June, 2014).

One of the sewage treatment ponds

I am concerned at the assumption that these treated waste water discharges are okay. I have been

told by the previous CSA that his inspections were fairly cursory. The literature on the impact of

sewage pollution of coral reefs is mixed. There is some evidence that in open ocean areas secondary

treated sewage, rapidly diluted, has relatively little impact. By contrast there is a growing body of

evidence that sewage pollution can be contributing to reduced reef condition (Reopanichkul et al.,

2009), harmful algal blooms (Lapointe et al., 2005) and indeed to coral disease (Sutherland et al.,

2011; Voss and Richardson, 2006). There will be a local impact, and it would be useful to

characterise that impact and to consider if there are simple interventions which might reduce this.

11

It is not possible, without evidence, to say that all is fine. On future visits it would perhaps be

useful to visit the adjacent beach area and even (at low tide) walk out to the actual outfall, but

such observations are insufficient to understand any impacts on the adjacent reef. There should

be some water quality sampling at surface and across a depth profile around the outfalls and

adjacent reef areas so the imprint of this pollution can be more accurately described. It would

further be valuable to assess ecological impacts though diving or video surveys.

Waste and recycling

Broadly speaking

Metal waste is stored to be taken for recycling. This is collected every 2-3 years by a

commercial company who buy this waste. This process includes entire vehicles.

Toxic waste is dealt with by HazWaste site, and aim is to shift off-island

Green waste from tree-cutting etc is held in green waste dump

Glass is pulverised, mixed with aggregate or soil and used as landfill cover material

All other waste is taken to incinerator and landfill

At the disposal plant all incoming waste around 10 tonnes per day is sorted by hand to remove

glass, metals and toxic matter (batteries, paints, aerosol cans, adhesives). There are two

incinerators, with one running and one in reserve.

Hand-sorting of waste (left) followed by twin chamber incineration

The output ash represents an 80-85% reduction by mass this ash is tested (twice a year) for toxicity

(e.g. presence of heavy metals). If toxins were detected above predetermined maximum levels the

ash would have to be treated as hazardous waste, to be shipped to the US for proper disposal (it is

not clear this has ever happened).

The ash is then taken to landfill pits, where it is covered, typically daily before the close of business.

The cover material consists of a mixture of soil, aggregate, sandblasting grit and pulverised glass or

mulched tree limbs. These landfill pits are lined and leachate collects along a channel along the W

margin. This leachate is tested on a monthly basis. It is pumped to deep storage at 180 ft depth

below the atoll below the landfill (and thus far from any freshwater wells). It is not clear to any of us

whether this means of disposal is better or worse than adding this waste to ongoing sewage

treatment, which is more typical.

Current waste pits were planned to last 30 years. But last year there was a complete failure of both

incinerators for 8 months. A decision was taken to dump the waste, without open burning, in same

12

pits (CSA was consulted and was ambivalent about possible advantage of burning, while open pit

burning was actually not permitted under Final Governing Standards). 8 months unburned waste

(which was still sorted for metal and toxics) used up 5 years equivalent of landfill with ash. There are

no plans to re-treat this waste.

Fish catch from illegal vessels this can amount to several tonnes. This is buried, unburned, at the

north end of the old (unlined) landfill site. It would be interesting to know if there are concerns

about this waste, either in terms of volume or leachate, and whether there might be alternatives.

Until 2007 waste was burned in open and unlined pits. This material was covered over by a 4ft cover

of the sand dug from the new pits. From 2007-2011 some open pit burning continued for the

removal of wooden materials (pallets and construction debris) with BritRep approval all such

burning is now prohibited under the Diego Garcia Final Governing Standards 2011. Clearly there will

be ongoing leaching from these old landfills for decades. This is NOT being monitored (see pollution

in the lagoon, below).

All toxic waste is processed with HazWaste, indoor facility where it is held prior to removal from

island. A large amount of asbestos remains on-island. Some has been buried, some was taken off-

island, the rest is not stored with HazWaste, but there is no clear plan for what to do with this.

The small arms firing ranges are also a source of toxic waste (primarily lead and other metals). The

waste (spent bullets) are removed from these sites through a process of sifting the sand bank behind

the range on a regular basis. I believe this waste is treated as hazardous and taken off-island.

The southern firing range

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Pollution in the lagoon

There are ongoing water quality studies across the lagoon, and these are being used in a new review

which is also modelling water flows studies and investigating the condition of lagoon corals. While

these findings are eagerly anticipated it would also be valuable to get an understanding of the

wider, ongoing water quality testing work and its findings.

We need to assess if there is any sign of leaching from the old (unlined) waste disposal site

influencing the recent and/or the ongoing water quality assessments in the lagoon and to follow

up with a consideration of the value of any further review of this hazard.

An environmental officer on Diego Garcia mentioned a red tide event (a bloom of planktonic algae,

typically dinoflagellates) in the lagoon ~8 months ago. He bought this up as an example of the sort of

thing that could be linked to the draining of leachate into the lagoon. Whatever the cause (and

these can be natural) they are a potential human health hazard as well as a threat to marine life. It

would be valuable to know more about any previous such events and to develop a reporting

mechanism.

Energy supply and generation

There are two diesel power stations on island. Storage facilities are replenished as necessary.

Fuel is pumped from a special port (POL Pier) via fixed pipelines and a twin pollution boom is

deployed when fuel is pumped (high winds and heavy waves during a recent pumping exercise led to

an order from BritRep for pumping to be halted as waves were breaking over the booms. Initially

there was some objection to this by the suppliers.

The POL Pier with pipelines and pollution boom

The fuel pipelines for different fuels are currently slightly over-hung by some large trees. There is a

requirement that overhanging branches be cut to reduce risk of damage to pipelines but the

responsibility for this is under dispute. Although unlikely, a tree or branch-fall on these pipelines

while fuel is being pumped would be most unfortunate. The problem of large trees/branches

overgrowing the fuel pipelines should be resolved.

On renewable energy, there are also plans for a major new photovoltaics installation near Fuel

depot. (This area is currently grass and scrubby ironwood forest.) It is somewhat surprising that

there is no heat capture from the incineration plant as this could also be used to generate energy.

Coastal engineering

Coastal erosion is a major problem in several parts of the island as identified in the Moffat and

Nichol report (Moffatt and Nichol, 2013). Prior efforts at coastal defence have involved ad hoc

armouring or dumping of concrete and other materials, but major efforts are now underway for

14

well-engineered revetments. Some of these were built in 2011/2 and work is now continuing to in

front of CPO Club

There is a potential impact during building of sediments being re-suspended and moving to

surrounding areas. Given the high sensitivity of corals to sediment damage, it is fairly common to

adapt coastal engineering practices to minimise these impacts, for example using sediment skirts to

surround areas of work (PIANC, 2010). I was told that work is undertaken at low tide and it was

suggested (though not clear) that work may be halted if large sediment plumes were being

generated. It is not clear whether this is really being put into practise or how effective it might be.

There were no reefs visible in the immediate vicinity of these works, and it is possible that most of

the sediments are quite heavy sands which might rapidly resettle. Even so, it would be valuable to

know if this threat was properly appraised, how effectively the simple measures are being applied

and what reasoning was used in assuming further measures such as sediment skirts were not

considered necessary.

Edge of existing revetments (2012) in front of BOQ7 and adjacent beach with material in place for building revetments from here to CPO Club

Understanding of the impacts of coastal engineering is never simple, and even the most rigorously

researched and planned interventions can lead to unexpected consequences elsewhere. The

proposals for engineering work recommended by Moffatt and Nichols appear to be thorough,

however there would be some value in getting an independent expert to review these. Even if they

are well-planned, it might still be expected that such interventions could lead to changing patterns

of coastal erosion and deposition elsewhere

A substantial revetment has been built beneath the lighthouse at Mini Mini. There have also been

two very minor coastal defence efforts in southern DG (ocean side) and western DG (lagoon side)

using large rock armouring, where the road is been threatened by erosion. These were opportunistic

dumps, without any effort at design, and are unlikely to be highly effective, but equally not likely to

be having any negative impact.

The other fairly regular form of coastal engineering is dredging to maintain deepwater ports and

channels. The previous CSA expressed concerns about the storage of dredge spoil and a storage area

was set aside. It would be useful to know if there are any impact studies of sedimentation from

these activities and to know more about the use of siltation avoidance measures such as siltation

skirts (PIANC, 2010)

15

Imported aggregates for coastal engineering

Aggregates are shipped in from Mauritius (with an earlier load of granite from Malaysia). Clearly

there is a risk of shipment of soil or living plant or animal matter. Current policy is that for any new

load a 25lb sample should be submitted and held in quarantine for 45 days. This is placed outdoors

on a concrete pad by the Pest Control Shop. After this bulk transport is offloaded at the open area by

the Port Ops. An authorized representative of the Contractor and/or quality control representative is

required to visually inspect each load of the material in the presence BIOT customs or British

Representative. Materials are then held in quarantine for 14 days to observe if any foreign plants

are present. 14 days is insufficient for germination and growth of many seeds, and the most

important part of this task is the inspection of materials, and indeed the inspection of the materials

prior to loading in the port of origin by the contractor, which is also a requirement under US

regulations on this issue.

A brief visit to the newly arrived and quarantined rocks showed the vast scale of operation with

aggregates from gravel to very large rocks. I walked around and up on to some of these piles and did

not see any sign of soil or vegetation. Both PWD and Britrep were at pains to assure me of the

lengths they go through to avoid contamination and this is now doubtless the case, although

originally concern was raised based on an opportunistic observation of contamination by soil, seen

by the previous CSA.

Some of the substantial stockpile of imported aggregates for coastal engineering

Overall it seems likely that reasonable measures are being taken here but the risks are very high and

the costs of just one aggressive alien introduction could be enormous. Vigilance remains key

clearly the contractors have prime responsibility, however the US and the British Authorities as

independent verifiers at the port of arrival should take their roles seriously. Advisory

documentation should be developed building on the experience of current customs staff, clearly

stating these risks and explaining in simple terms the process for conducting thorough customs

inspection prior to and during offloading.

16

Marine and Fishing

Monitoring of legal fishing

Boat-based fishing from DG

Personnel on DG are able to fish from a number of boats, notably 3 Makos and 3 Boston Whalers

which are booked prior to use.They mostly used at weekends. The Boston Whalers can fish outside

the lagoon (this has been recently re-allowed, following a period of closure linked to an accident in

2011). There is also an LCM (Landing Craft Marine) which goes out on weekends this can

theoretically take ~50 but will typically take up to 15 people trolling outside the lagoon.

With the lagoon a large area is open to fishing, but this this area is zoned, with fishing rotated

around zones through the year. Prior to this visit a member of the recent science expedition had

expressed concern that fishing in the lagoon was having a clear impact on grouper populations. They

also suggested that there might be some fishing from the large vessels at anchor. An impact on the

grouper population is quite likely, but it is more likely this a result of the small boat and coastal

fisheries. The vessels at anchor have only a small crew, they are very high out of the water, and they

have relatively small spatial footprint over non-reef (or former reef) areas. There still remains a

need to ask US commanders to confirm activity from large vessels at anchor, and regulate

accordingly.

All boats must report catches numbers of lines, area visited and fish caught, including weight (not

number of fishers, or numbers of hooks sometimes fishers will have multiple lines and several

hooks on each). These forms are managed by MWR and entered into a spreadsheet forms and

spreadsheet are sent direct to MRAG for analysis (SFPO is copied). John Pearce at MRAG is

responsible for this data.

Generally big game fish (marlin/sailfish) are not targeted and are considered quite rare.

Shore fisheries

This takes place 7 days a week on both inside and outside of DG, including much is evening and night

fishing with lights. Reports from shore-based fishing are voluntary so are likely to be a large under-

estimate of catch. There is no real incentive to report catches, while the perceived risk of infringing

poorly known regulations is probably a strong disincentive. Further many of the fishers have poor

English and most would not be aware of the fish names in English.

Better reporting of the full recreational fishery around DG is clearly needed. SFPO suggested that

anonymous reporting, with forms in native tongues, might improve returns. A system of rod

licensing could further help as owners of rods would be asked why not returning fisheries forms.

Another creel survey for all fisheries would be very valuable, but would need a thorough and

systematic approach. (The best creel study to date by MRAG apparently also suffered from

considerable under-reporting.)

Yacht fisheries

Yachts are permitted to fish for personal consumption and on application for permit to visit are also

given digital form for reporting their catch this would be reported direct to MRAG. There is also a

folder and pile of blank forms in Salomon, but this was gathering damp and dust and had no

completed forms.

On visiting yachts UK Customs generally do not search boats, but would look for signs of illegal

activity (spearguns, coconut crabs, dive gear) which could then lead to more complete search. They

do sometimes ask them about fishing but not in any detail.

17

A detailed description and summary of the information from the DG and yacht based fisheries

return forms should be obtained. We need to consider how to improve returns on the shore (and

possibly yacht) fisheries. There would be great value in commissioning a new creel survey to

assess these fisheries.

Surveillance and capture

Operational details of the fishery surveillance and capture activities and capabilities have been noted

by the CSA, but, due to the sensitive nature of such information, they are not presented in full here.

Earlier public reports detail the only Sri Lankan vessel captured in 2013 (BIOT Government, 2014a)

and suggest that this single capture may be part sign of a decrease in IUU fishing resulting from both

UK patrols and Sri Lankan measures to control flagged vessels. There have, however been 2 arrests

already in 2014 which are still sub judice.

With Sri Lankan vessel arrests the vessels are taken into DG where the catch details are documented,

prior to burial (see waste). Recently a new approach has been developed vessels charged and are

taken to DG where the catch is offloaded, but they are then allowed to return to Sri Lanka while the

owners are prosecuted in absentia and fines are pursued through bilateral and multilateral

agreements (BIOT Government, 2014a).

MRAG have also provided a report of an IUU incursion by a Taiwanese longliner in 2013 which was

observed, but refused to co-operate, abandoning lines in BIOT waters. There has been some

cooperation from the Taiwanese government, within their own legal parameters, and the vessel was

tried in absentia and subject to a 195,000 fine plus 5000 fees it offered 30,000 in settlement

but this has not been accepted and the case continues (BIOT Government, 2014b).

It must be remembered that with such IUU fisheries, observance and capture can be highly

influenced by both the skill of the patrol crew, the avoidance skills of the IUU vessels, but chance

also has an influence on the total numbers of captures. The Sri Lankan vessels are small, but are also

slow and have no radar, making interception and capture more likely. By contrast the tuna vessels

are a considerable challenge, as witnessed by the evasion of the Taiwanese vessel in 2013. The main

tuna season is Oct-Feb, and there are regular patrols, but the large radar horizon and the speed of

these vessels makes capture a challenge.

The FPV may already be having a valuable impact on the illegal demersal fishing, although it is

difficult to quantify this success in terms of the proportion of IUU vessels that are captured, or the

deterrent value. There is a far greater challenge to impact possible IUU tuna catch. For both

fisheries there is a need to try and ascertain the levels of illegal fisheries irrespective of capture.

Following discussions with BritRep, XO and SFPO, there appears to be some possibility for more

engagement with DG in surveillance.

BritRep has established protocols to encourage reporting on the presence of possible IUU vessels in

BIOT waters by incoming and transiting military and civilian vessels and planes. In some cases

BritRep and/or SFPO could advise them on course to maximise coverage or complement existing

surveillance. Not all observations could be acted on, but proportion of illegal vessels of those acted

on would be indicative of pressure. Is there also possibility of using past satellite imagery to look at

vessel traffic in Chagos waters to ascertain use in different sectors.

18

The current SFPO was widely praised for his abilities in patrolling and interception, with an

observation that such skills are not always expected, and yet are clearly more important than the

now redundant abilities of fisheries management.

It might be possible to improve policing with a more co-ordinated approach and some sharing of

surveillance data between BIOT officials and their contractor (MRAG) in real time. A previous MRAG

SFPO had shared six-hourly position and activity reports from the FPV for 4 months 2013-14. Plotted

these show areas of patrolling and linked observations of FADs and ship interceptions. The sharing of

such information is currently not in the job description of the SFPO and there may be concerns of

interference or even conflict of interest as SFPO is employed by MRAG. On the other hand such

information is clearly valuable and MRAG also holds presumably very large volumes of such

surveillance information over many years and these should be made available to BIOTA for future

use in a broader review of surveillance approaches and for possible sharing with other/future parties

being engaged in this work.

In the short-term there could be value in encouraging dialogue and collaboration between MRAG

and the BritRep/BIOT team on-island to encourage some further data-sharing around surveillance.

There were also discussions about other novel surveillance approaches:

Placing web-cams on the islands for surveillance

Aerial surveillance with drones

Marine surveillance with Remote Operated Vehicles

There could be security concerns with deployment of these active, but unmanned approaches,

however these would be surmountable if BIOT authorities were linked to surveillance and able to

develop the policy. UK and US military could remain fully informed and could perhaps influence such

work to avoid sensitive operations.

The above came from a real interest in a more formal engagement of Royal Navy in surveillance.

They are expert at it!

The BIOT patrol vessel is performing an excellent task for the resources available to it, however

there are significant limitations in its capacity. This is due to its size and speed, but also to the

multiple requirements of its mission, which include patrolling, science expeditions, customs and

immigration, Chagossian cultural visits, the resettlement feasibility work as well as official visits from

CSA and other government representatives.

In making plans for ongoing and future surveillance it would be valuable to have a rational

discussion with all players on vessel and surveillance needs, science support and possible options.

There are clearly different opinions, but also challenging budgetary constraints.

Shark human interactions

A recent fatality at the popular beach and marina has led to a number of regulations on swimming

(in pairs and during daylight hours). I would be interested to know if there has been a more

thorough review of this. One attack of this nature in 40 years is not a high rate, and there probably a

risk of excessive caution, rather than a need for tighter regulation. The impact of reducing access to

the water would perhaps be more on morale and welfare, however I do feel that maximising safe

access to nature by island residents is an important means of raising environmental appreciation and

awareness. It is perhaps worth pointing out that reef sharks are a major draw for tourism in many

coral atolls, including many popular beaches where small reef sharks are abundant (Anderson and

Waheed, 2001; Gallagher and Hammerschlag, 2011; Vianna et al., 2012).

19

Even so, there may be a place for some improved information and management amendments to

reduce risks of shark-human interactions, while maintaining or even enhancing overall access to

the lagoon and these should be further investigated. For

example it would make sense to separate swimming from areas

where coastal fishing is popular and from the dock where fish

are landed. Measures might be put in place for greater

separation between boat-based fishing areas and areas used

for in-water recreation. It would also be valuable to develop

some posters to explain the risks (for example reef sharks are

non-aggressive and generally safe but: non-fatal bites have

been associated with presence of food in the water, typically the

threat is greater if water is murky and in shallow water where

sharks may be feeding, and where only part of a body is visible

to them (typically ankles)). Actions on this front should be

undertaken with the participation, and funding, of US MWR.

Similar consideration needs to be given to Salomon anchorage

area. Reef sharks are permanently present under the yachts.

Better information might help to reduce the residual risk of

accidental attacks.

Two small lemon sharks feeding in knee-deep water in the eastern lagoon area near Barton Point.

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Biodiversity Conservation

Habitat Restoration

PWD have a formal policy of replacing every tree cut down with two planted. They apparently

greatly exceed this ratio at the present time. Previous CSA made the point that these hardwoods are

far more water efficient than coconut forest so there could be significant water recharge benefits in

such activities.

From a habitat restoration perspective, three small sites have been a focus of restoration, largely led

and encouraged by Major Peter Carr, former XO. I visited the southernmost two of these briefly and

made a more thorough tour of the furthest site beyond Minni Minni, (Barton Point Hardwood

Restoration Site). In all sites the original donkey fencing is somewhat dilapidated. There is quite a lot

of hardwood growth, including a good variety of native trees: Intsia bijuga, Barringtonia asiatica,

Guettarda speciosa and Morinda citrifolia were among those identified

Damaged fencing in the Minni Minni Plantation

Left to right: Guettarda speciosa, Intsia bijuga and Morinda citrifolia

There is a need to track down any reports covering overall policy, species planted, area covered

(maps?), techniques deployed; follow-up or proposals for follow-up. These should be used to

provide advice on future efforts.

There is a possibility of engaging existing ground-staff and/or volunteers to extend this work.

Current grounds management in this area is poorly planned and ad hoc, so such guidelines could

yield significant benefits at no cost.

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There may also be a need for a field based review of these projects. It would be valuable to know,

for example, about the relative success of different native species, the importance of nursery

saplings versus natural regeneration, the threat of donkey grazing, the effectiveness of different

measures, including fencing, or coconut cordons. Equally understanding the relative costs and

benefits of different approaches would be helpful if natural regeneration is only slightly slower, but

comes at a fraction of the cost of nursery rearing, planting and fencing large plots it might be

possible to progress restoration over much wider areas for similar costs in terms of funds or labour.

In the absence of more information I would suggest that the most effective and rapid gains around

restoration would be to encourage natural regeneration in areas of mixed coconut and other native

forest areas where there are already saplings. Here efforts could focus on removing coconut palms

and using trunks, coconuts and debris to build cordons around priority native saplings as protection

against donkey grazing

The previous CSA also spoke of wetland restoration I did not follow up on this, but did note that

one of the artificial ponds adjacent to the airport had been drained for clearance and re-filling. It

would be useful to know more about this, and its conservation relevance

Invasives

Currently on DG the regular invasive controls are on rats, cats and chickens. Chickens are perhaps

gone. An environmental officer on DG estimated 8 individual cats have been seen and extrapolated

from this to perhaps 20 in total on the island. Rats remain abundant, though less so downtown due

to ongoing poisoning. Brown and black widow spiders are spotted on occasion inside buildings,

when this happens a team is sent out to remove them with insecticides. I am also aware that some

training is run twice a year on the brown tree snake risk for staff likely to be handling cargo from off-

island. There is an ongoing study of rat eradication, with possible idea of DG eradication programme,

it would be useful to know more about this.

Invasive plants are not being actively managed except as part of other ongoing site work which can

include quite thorough removal of Ironwood and Mimosa.

No other invasives are actively pursued. Britrep suggested it would be helpful to have an official list

of pest species to guide removal policy.

Rat Eradication

A brief circumnavigation was made of Ile Vache Marine (scheduled for eradication in July). Some

cross-island transects have already been cut and locations for others are prepared. This looks a

highly manageable island for the work in terms of island size and vegetation.

Public engagement

One of the most important tools in effective and ongoing environmental protection is the

engagement of local people, in this case island personnel. If people are able to enjoy their

environment it is much easier to engage them in caring for it.

Many island personnel are already highly active in the natural environment, through activities such

as cycling, snorkelling, sailing and fishing. It is also highly positive to note a number of activities that

do encourage or foster such engagement, including:

the biannual tip to tip bike race,

the viewing platforms at Turtle Cove,

18 miles of jogging/walking and off-road biking trails

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Earth Day (April) and Sea Turtle month (November)

Fun runs

Weekend bus-trips to the Settlement,

ongoing turtle monitoring work,

beach cleaning exercises (which, one might argue are a product of good public engagement)

there is also a proposal from MWR (Morale Welfare and Recreation) to develop a forest trail

for access by solar charged Segways,

To further benefit from this kind of outreach there is a need for more direct communication and

education and there could be considerable advantage in development of more signage or other

more active communications. The materials (postcards, booklets and information sheets) produced

by CCT are certainly a positive contribution, but are probably somewhat hidden from most people. It

would be valuable to encourage direct communications through the radio/TV, and to strongly

encourage visiting scientists to give presentations. (I did offer and there was enthusiasm, but no

time to organise as BritRep was off island during latter part of my stay).

Signage like this at Turtle Cove presents an important opportunity to reach out to island residents and engender greater support for environmental issues on Diego Garcia.

Boats in northern atolls

While I only joined a customs visit to one yacht, in general the customs visit consists of a brief

passport and permissions check. It might be valuable to use this visit to remind yachts of the rules,

encourage them to return the fisheries forms and of course to keep an eye out for any evidence of

rule breaking.

Waste

Yacht waste is collected from Boddam and Ile de Coin. On the former the bins were overflowing and

one bag was on open ground (and had been ripped open by crabs). In all cases the trash appeared to

be uncrushed and could have occupied half the volume.

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Waste on Salomon (left) and on Boddam (right) bins were full, but much of content was uncrushed plastic bottles and cans, with excess dumped on the ground in breach of regulations

Current signage for waste disposal on Salomon unreadable, and not encouraging

It would be valuable to create some clearer and more forceful (and explanatory) signage to

encourage correct behaviour. This is probably a task that needs repeating on occasion as signs will

fade, become outdated or simply look old and be ignored. Where there is evidence or reporting

of particular culprits these should be followed up, at lease with an expression of concern.

Anchors

Over the years, concern has regularly raised about anchor damage to the sea bed in the northern

atolls. More recently boats were restricted to five mooring sites where they can moor or anchor.

We dived under two yachts but unfortunately in both cases the yachts were attached to fixed

moorings so anchor damage was minimal. I am not clear whether these moorings were installed by

BIOT, or with BIOT approval (historically there were demands for such moorings, but concerns were

also raised over insurance implications if BIOT put these in).

Undamaged coral gardens at 5-7m depth in Salomon Lagoon, showing the high diversity and complexity of reef structure (rugosity).

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This area really is an extraordinary coral garden with a high species diversity and very high rugosity

(structurally complex), making it highly vulnerable to anchor damage. There were certainly quite a

number of small patches that had been smashed, possibly by small anchors from dinghies coming to

Boddam from yachts further offshore. Under the second mooring there was a more extensive plain

of flattened substrate, but this appeared to be associated with a shipwreck.

The unusual and highly diverse nature of the Salomon Lagoon gives it a very high conservation value,

already much commented on. I am, however, unaware of whether this importance is contiguous

across the lagoon, or hence of the relative importance of this anchorage site in relation to the lagoon

overall.

It would be valuable to obtain a more detailed understanding (either from data already gathered

from the ongoing science expeditions, or from a new survey) of the distribution of important

benthic habitats across the wider Salomon lagoon, and perhaps to undertake a (necessarily more

sparse) survey of seabed features in Peros Banhos in order to ascertain the relative importance of

anchorage sites.

The observations from Salomon also underscore the importance of fixed moorings.

Patches of damaged coral in Salomon linked in the vicinity of the fixed moorings. Damage like this could be created by a single anchor and chains in a matter of days.

The FPV anchors with large chains across the archipelago. It was noted that the ship has a number of

fixed locations marked on its charts where it always anchors and this is doubtless important these

are effectively sacrificial sites needed to support the work of the FPV.

There would be some value in detailing the exact GPS locations of these anchorages for any

change of personnel or for use by other licensed vessels to ensure that damage remains

contained.

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Science and observations

Facilities

At present a large amount of science kit (mostly Darwin Project) is being held in small air-

conditioned store near the marina and funds have been made available to convert a larger space in

part of the vehicle maintenance area of UK forces. This looks like an excellent space. There is also

already plumbing and I suggested that they consider using the end wall as a small lab-space which

could be immensely valuable to future expeditions. This was felt to be an easy adaptation.

Coastal erosion

Aside from the Moffatt and Nichol report, which deals with the inhabited area of DG I am unaware

of other studies on erosion across the rest of DG, other than the recent debate between Sheppard

and Hamylton on DG (Hamylton and East, 2014; Sheppard, 2014). While I did make personal notes of

erosion/deposition, it is important to note that such observations have little value in ascertaining

overall processes around the islands.

Clockwise from top left: Erosion on E Eagle island, showing collapse of former settlement buildings in to the sea; erosion on the protected lagoon shore of Middle Brother; erosion of lagoon shore in Diego Garcia with eroding dune scarp; recent colonisation of newly deposited sand on Ile du Coin, Peros Banhos (note that these are very young plants could be less than one year old and this may not represent any permanent new ground on the island.

Overall erosion is widespread on many islands including: W Eagle, large parts of Middle Brother,

parts of N Ile de Coin (lagoon side), N shore of Moresby (ocean side), and outer margins of S and E

shores of DG. In all or most of these cases the erosion is undermining mature trees, suggesting that

this is novel. By contrast deposition is rarer quite a number of islands on Perhos Banhos showed

26

sand banks extending to north and south or on most sides of Ile Vache Marine, however the lack of

any substantial colonisation suggests that such extensions are probably seasonal (confirmed by

SFPO). There is some new colonisation by coconuts and Scaevola on the W end of Ile de Coin.

On DG, Eagle, Moresby and Ile du Coin there is clear evidence of over-topping of some island

margins, visible in terms of debris transported inland. Over-topping is a natural process on atolls and

indeed is a necessary part of island formation and so it would not be advisable to use this evidence

as proof of a growing threat of sea level rise or of risk of island loss. At the same time, inundation

and erosion will be the mechanisms by which sea level rise begins to impact islands, along with the

salinization of freshwater lenses.

The most important message from these observations is that there is an urgent need to get

observations like this onto a solid science footing. Atoll islands are naturally highly dynamic. Sea

level rise is a clear and important threat, but will not need to loss of territory in all places. A

reliable long-term study, using air photos for recent history and setting baselines for even more

detailed annual assessment could be critical for long-term planning, both for conservation and for

current and future human use of the islands. Such a study should be led by those with an expertise

in tropical geomorphology as suggested in Hamylton and East (2014).

Fishing impact

There is legal fishing in DG, from the yachts, and from the fisheries patrol vessel. The yachts are

probably having a localised impact in the lagoon (no large groupers were seen in the lagoon dive

there). In DG there is no information regarding the large shore-based fishery. The FPV is not a large

ship and is patrolling a very large ocean, however concerns have regularly been raised by scientists,

both that there may be some impact, and that this is not sending out a good signal in what is

regularly described as a no-take MPA. Currently fishing from the FPV, even in the strict nature

reserves, is legal. While there would be only weak ecological justification for closing all fishing

from the FPV, there would be some value in establishing some additional limits, with the closure

of some areas. The primary aim of such an approach would be to curtail any future expansion, but

also to signal the importance of no-take in Chagos and to ensure that some locations are truly

without any fishing impact. Closing all fishing from the FPV would probably be counterproductive.

Mangroves

There are two known areas of mangrove in the Chagos Eagle and Moresby Islands. Both have been

described by scientists in the past as threatened with loss through overgrowth by coconut, parasitic

plants or drying out and there have been calls for management intervention.

The two communities are very different:

on Moresby the mangroves we visited were growing around two, interconnected,

mangrove-fringed lagoons that have no direct connection to the sea. These give way to

mixed forest on one side and to Pemphis acidula a rocky berm and then the N coast.

Although they are only a few metres from the sea in places, this higher island margin, with

quite a lot of rocky debris, is a permanent barrier which would only be overtopped by storm

waves. Subsequent to this visit SFPO has returned to these mangroves and confirmed that

the mangroves are intertidal, drying at low tide, and with water bubbling up through the

substrate as the tide turned. During our earlier visit the water in this lagoon was brackish

rather than full salinity, showing that is it fed both by the sea and the freshwater lens. Trees

were large (some reaching 4m), but none were observed in flower and there was apparently

no recruitment. A few trees were dead or dying, but the majority appeared healthy.

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Although this is a (heavily!) ratted island the mangrove was a rich nesting ground for red-

footed boobies even on branches at low elevations over the water. Presumably they are

benefitting from the waterlogged substrate which might prevent rat predation.

Top: Mangrove lagoon, Moresby Island, Peros Banhos Bottom: Mangrove community on Eagle Island, growing amongst grasses and some coconut trees (left) with occasional patches of denser mangrove cover (right)

On Eagle the mangroves are more clearly inland and while the site is usually (SFPO pers

comm) waterlogged we visited at low tide and it was largely dry. The mangroves are quite

extensive but mostly in a number of mixed associations with coconut, grass, fern and some

hardwoods. Towards the central more open area many larger (4m plus) trees were dead or

dying, but the cause of death was unclear, it was not overcrowding, and there were a

number of dead or dying coconuts. In one area apparently healthy low-stature bushes (2m)

were in a solid formation, but nearby similar trees were being strongly overgrown by the

parasitic dodder (Cassathya). The latter is a native species, however and this is presumably a

natural phenomenon. Unlike Moresby, quite a number of the mangroves were flowering and

there was recruitment.

From the observations of the mangrove forests it is not clear that any urgent management

intervention is needed, but ongoing scientific observation and perhaps more detailed mapping

and description would be valuable

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Reefs

Dives and snorkels were undertaken at eight locations. There is enormous variation in the reef

communities with depth and location, and much of the highest diversity, coral cover and fish

abundance is located in waters 5-10 depth (beyond easy snorkelling range). Given that coral reefs

are among the most important habitats in BIOT it would be difficult for the CSA to fully assess

ongoing science or raise key issues without at least some recent experience of these habitats and so

it took some organising to be able to dive, it was important for the CSA to be able to see these.

The CSA kept basic site descriptions and these have been used to develop the following comments:

Coral condition and disease

Initial observations from the leader of the recent science expedition warned of a widespread loss of

Acropora plate corals and some disease. Coral disease appeared to be widespread although was very

largely associated with plate Acropora corals. These corals are, or were, dominant in many reefs,

perhaps more so than they were prior to the 1998 coral death event. They are generally rapidly

growing species that filled large areas of reef tract.

Disease and recent coral death was mostly confined to plate Acropora, but this partially bleached, partially dead massive coral was photographed in the lagoon near Barton Point

There was variation in die-back, and of course it cannot be assumed that all dead corals have

resulted from disease, but in some areas, notably off the west coast of Eagle Island a majority of

coral was dead and new recruitment was relatively low.

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Detailed reports on disease are expected shortly from the most recent science expedition and

should be given close attention.

Fish and shark populations

Fish stocks appeared healthy, with large numbers of groupers and snappers in most sites. There was

possibly some evidence of fishing pressure in Salomon Lagoon and a slight indication that large

grouper numbers may have also been a little reduced on the outer slopes of S Ile Anglaise which is

likely to be a popular fishing location for yacht-based fishers.

Sharks were abundant on most dives. Clearly the sample was too small for any scrutiny, but these

included 5 common reef shark species (whitetip reef, blacktip, silvertip, grey and nurse sharks, with

2 lemon sharks observed feeding in DG Lagoon).

Lagoon reefs

Lagoon reefs were visited in 3 very different settings. Ile Vache Marine (very brief snorkel), which is a

somewhat exposed lagoon/fringing reef had very high cover of live plate Acropora with little disease

observed. Salomon lagoon has remarkably high coral cover, with considerable diversity (at least of

coral morphologies, experts are needed to comment on species diversity). Anchor damage was

present, but not widespread in the area visited (about 300x25m). Finally a snorkel over the back reef

areas towards the mouth of DG Lagoon (Barton Point) showed an extensive area of shallow reef

dominated by bare rock with algal turf) and some larger, stable areas of rubble, but with numerous

massive Porites-like corals, forming fields of micro-atolls in shallower areas, and some robust

branching colonies (Pocillopora-like). This DG reef was probably impacted by bleaching some time

ago (1998) explaining the branching coral rubble, and also the recovering growth forms of some

massive corals.

The healthiest plate Acropora colonies were observed near Ile Vache Marine, but even here there was disease and some areas of substantial die-back

Turtles

Green and hawksbill turtles were observed in multiple locations in the Northern Atolls and are of

course still abundant in Turtle Cove. Nesting tracks were observed in multiple locations around DG,

Nelson and Ile Vache Marine. It is now over 40 years since turtles were harvested and 18 years since

Jeanne Mortimers extensive island-by-island assessment of nesting (Mortimer and Day, 1999). It

would be valuable to know if the science is delivering any information on change in nesting rates.

Island erosion and beach litter are both likely obstacles to nesting in a few places, with the steep or

vertical sand or root margins of eroding shores being perhaps the greatest obstacle, but it seems

unlikely that these would be limiting nesting capacity. In 1996 Mortimer and Day estimated length of

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suitable nesting beaches for most islands in Chagos (Mortimer and Day, 1999): it would be

valuable to know whether this extent is being reduced by changes in island morphology.

There is a strong commitment from the current XO to supporting turtle monitoring which is being

linked directly to the academic research community (see below).

Citizen science and conservation

It is clear that engagement of DG personnel in conservation work is providing science and

environmental benefits notably beach cleaning and turtle monitoring, but also past efforts at

habitat restoration. I would include in this the important work undertaken by UK personnel on the

northern atolls such as beach clearance and rat eradication. As mentioned this sort of engagement

produces benefits to the environment in other ways, notably raising awareness and increasing

concern for protecting the environment, but also in terms of morale and welfare. There is clear

enthusiasm on the part of senior personnel on the island, and indeed a long history of such

enthusiasm and engagement both at levels of senior officers and in terms of volunteers from across

the military and civilian personnel from all nationalities. A significant limitation on this work is the

capacity of key senior personnel, who have to fit such work around what are already highly

demanding schedules.

It would be useful to develop a summary of the contribution of this work to date, and to review

and describe the range and potential for future citizen science work. This might serve to

encourage ongoing and new efforts, and aid the transfer of skills and knowledge to new

personnel. This might include species monitoring (plants, birds, turtles, coconut crabs, invasive

species); beach clearance and reporting; invasive plant removal, tree-planting and even marine

science, from snorkel, fishing-based sampling or even diver surveys. Diving by personnel on Diego

Garcia has been allowed in recent years, however it is not strictly permitted as diving is meant to be

for science or maintenance/infrastructure work only. Establishing a simple programme of citizen-

science diving would help legitimise any restoration of diving activity and could be very valuable.

This would need careful discussion and thought, but there are many programmes available which

allow for training and delivery of simple survey data by non-scientists on coral reefs.

There has been some discussion about the use of a 6-month volunteer/low paid intern to run basic

science around DG this could include supporting citizen science, but also some basic ongoing

science observation, conservation work including restoration, and community outreach. It would

need to be funded, but it could be a valuable opportunity to increase some science reporting to the

CSA and the FCO, to other scientists and NGOs. They may also further enable the ongoing citizen

science work that continues to be supported by BIOT personnel. BritRep expressed concern about a

permanent presence of professional civilian scientists due to costs/logistics of running this with

current personnel.

Expanding the baseline

In so many settings there is a need to understand environmental settings around Chagos more

broadly in terms of geography and discipline (ecology, oceanography, geomorphology),

particularly in areas where there has been little or no observation to date (both in terms of

geographic location and key disciplines). This detailing of baselines is not necessarily the top priority

for academic research which favours detail, novelty and change, but is critical for providing the

comprehensive baseline on which change can be more certainly understood. Mention has already

been made of the need for detailed historical to present day geomorphological studies, and in

establishing baselines against which to measure future patterns of island dynamics.

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As ecological examples, the reefs encircling DG are unstudied beyond a handful of point locations at

the northern tip. Likewise I believe the extraordinary diversity on the seabed of Salomon Lagoon is

only really described from the southern end, the area most impacted by anchors and (presumably)

pollution. In both cases we have no idea of the representativeness of these known areas, we are

unable to judge if the protection (DG) or sacrifice (Salomon anchorages) are well placed. Further we

would be unable to recognise any major changes to these systems resulting from human or natural

perturbations.

Some of this science, is of particular relevance for human needs. On DG the long-term stability will

undoubtedly benefit from thriving reef communities generating new sediments and providing critical

natural breakwaters (Ferrario et al., 2014). There are also implications for any considerations of

resettlement beyond Diego Garcia.

A science plan already exists and work is underway to develop a conservation and management

plan. While there is overlap, it is appropriate that these should be maintained as distinct outputs.

Critical to such planning tools is a vision of need and prioritisation, particularly to guide the

necessarily limited budgets of the BIOT Administration, but also to help in the assessment of

proposals for other visiting scientists and the potential engagement of new partners in

conservation work.

In developing management plans and science plans there is also a strong need for a centralised

data store for environmental information on Chagos, including findings from the science, from the

fisheries patrol, and from non-sensitive environmental studies around DG by military and

contractual visitors. As much as possible should be made open access, with data-sharing protocols

to be determined and agreed to as an a priori requirement for all those working in Chagos. This

may be something the CCT and science leaders have already been pushing for.

Science and conservation work are both growing in quantity and scope throughout the Chagos.

Funding for such work is also growing and diversifying, from academic, philanthropic, NGO,

government and other sources. This is to be welcomed, but with this is an ever growing need for a

broader vision.

Closing comments

At the end of this first formal visit as CSA to Diego Garcia and the northern atolls it is important to

stress the positive impression given by all those I met and worked with. Diego Garcia is a very large

military facility in a remote and fragile environment and the efforts that are being undertaken to

preserve and indeed enhance this environment are impressive. The only counter to this is that they

should be. The BIOT is almost unique in the world now, in terms of its large area of healthy coral

reefs and undisturbed coral islands. Its importance will likely only increase relative to the ongoing

declines in many other tropical reef environments world-wide. There is thus what might be seen a

need or a duty to look after this environment above and beyond the normal best practises. An

alternative wording might talk about an honour and a privilege to be able to undertake this

stewardship in one of the worlds most pristine environments. In no place was I given the impression

that efforts are slacking, or that weaknesses are being deliberately ignored. I was given full access

and encouraged to ask questions and to inspect wherever I wanted. This open-ness is most

impressive and welcome.

I have of course raised quite a number of issues, listed at the start of this document, and in bold-

typeface throughout. Key among these are the need to better understand the possible impacts of

32

treated wastewater disposal directly onto the reef; the impacts of recreational fishing around DG

but also from the yachts in the northern atolls; the possibilities of improving surveillance and

capture through co-ordination with BIOT personnel and over the longer term through new

approaches. There is a need for new baseline science research, and for much greater sharing and

access to data describing the environment around BIOT; there could also be considerable benefits

from better environmental communications and efforts to engage and educate both personnel in DG

and visitors to the northern atolls.

These and the full list of comments need to be understood in terms of the positive impression

overall. They are intended to help to push, steer and guide towards greater improvements and to

avoid present and future risks.

Acknowledgements

I am most grateful to the BritRep and XO for their support and enthusiasm to help me understand

the islands and all the issues which might impact the environment. Thanks also to the US

Commanding Officer and to the staff of PWD for the invaluable discussions and the access and

guidance around several key facilities.

For the visit to the northern atolls I am grateful to the Captain and crew of the Pacific Marlin and of

to the SFPO for his guidance around islands and for sharing his broad ecological and fisheries

knowledge. Many thanks to my two dive buddies from the Royal Marines. Thanks are also owed to

the science expeditions for allowing us to use dive tanks and a compressor to enable this to take

place, and to the BIOT Dive Club for the loan of equipment.

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