SEYCHELLES MARINE CONSERVATION AND RESEARCH EXPEDITION CORAL RECRUITMENT PROGRAMME July – September 2008
A Status Report prepared by Global Vision International (GVI) for the Seychelles Centre for Marine Research and Technology – Marine Parks Authority (SCMRT-MPA), Marine Conservation Society Seychelles (MCSS) & the Seychelles Fishing Authority (SFA)
Edited by Paul McCann (Expedition Manager) & Rochelle Johnston (Science Officer) Cap Ternay Research Station, PO Box 1240, Victoria, Seychelles Email:
[email protected] Web page: http://www.gvi.co.uk and http://www.gviusa.com
© Global Vision International – 2008
GVI Quarterly Status Report No.083
Table of Contents List of Figures................................................................................................................... iv List of Tables .................................................................................................................... iv
Executive Summary…..………………………………………………………………...1 1.
Introduction................................................................................................................ 2 1.1 1.2
2.
Background ....................................................................................................... 2 Expedition Training ............................................................................................ 3
Coral Recruitment ..................................................................................................... 4 2.1 Introduction ........................................................................................................ 4 2.2 Aims .................................................................................................................. 5 2.3 Methods ............................................................................................................. 6 2.3.1 Hard Coral Recruitment Quadrates ........................................................... 7 2.3.2 Coral Predation and Algal Grazing Belt Transects .................................... 7 2.4 Results .............................................................................................................. 8 2.4.1 Scleractinian Recruit Density ..................................................................... 8 2.4.2 Size Class Comparisons ........................................................................... 9 2.4.3 Reef Substrate Comparison .................................................................... 10 2.4.4 Depth Comparison ................................................................................... 10 2.4.5 Family Specific Diversity .......................................................................... 11 2.4.6 Coral Predator and Algal Grazing Invertebrate Belt Transects ............... 13 2.5 Discussion ....................................................................................................... 14
3.
Turtle Monitoring ..................................................................................................... 15 3.1 Introduction ...................................................................................................... 15 3.2 Aims ................................................................................................................ 17 3.3 Methods ........................................................................................................... 17 3.3.1 In-Water Surveys ..................................................................................... 17 3.3.2 Beach Surveys ........................................................................................ 18 3.4 Results ............................................................................................................ 19 3.4.1 Focal Behavioural Study .......................................................................... 17 3.4.2 Beach Surveys ........................................................................................ 18 3.5 Discussion ....................................................................................................... 19
4.
Whale Shark and Plankton Monitoring .................................................................... 19 4.1 4.2 4.3 4.4 4.5
5.
Introduction ...................................................................................................... 19 Aims ................................................................................................................ 19 Methods ........................................................................................................... 21 Results ............................................................................................................ 22 Discussion ....................................................................................................... 22
Fisheries Assessment ............................................................................................. 22 5.1 Introduction ...................................................................................................... 22 5.2 Aims ................................................................................................................ 22 5.3 Methods ........................................................................................................... 23 5.4 Results ............................................................................................................ 23 5.4.1 Sea Cucumbers ....................................................................................... 23
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5.4.2 Lobsters ................................................................................................... 24 5.4.3 Octopus ................................................................................................... 24 5.5 Discussion ....................................................................................................... 24 6.
Cetacean Sightings ................................................................................................. 25 6.1 6.2 6.3 6.4 6.5
7.
Introduction ...................................................................................................... 25 Aims ................................................................................................................ 25 Methods ........................................................................................................... 25 Results ............................................................................................................ 25 Discussion ....................................................................................................... 26
Satellite Camps ....................................................................................................... 26 7.1 Curieuse Island ............................................................................................... 26 7.1.1 Introduction .............................................................................................. 26 7.1.2 Aims ......................................................................................................... 30 7.1.3 Methods ....................................................................................................... 7.1.4 Results ..................................................................................................... 28 7.1.4.1 Scleractinian Recruit Density ................................................................... 28 7.1.4.2 Size Class Comparisons ......................................................................... 29 7.1.4.3 Reef Substrate Comparison .................................................................... 30 7.1.4.4 Depth Comparison ................................................................................... 31 7.1.4.5 Family Specific Diversity .......................................................................... 32 7.1.5 Discussion ............................................................................................... 33
8. Community Development 8.1 8.2 8.3 9.
National Scholarship Programme .................................................................... 34 International School Work ............................................................................... 34 Annual Seychelles regatta ............................................................................... 34
Acknowledgements……………………………………………………………………….37
10. References .............................................................................................................. 36 11. Appendices.............................................................................................................. 38
© Global Vision International – 2008
List of Figures Figure 2-1: Total density of scleractinian recruits per m-2 around North West Mahé…… 8 Figure 2-2: Mean density of scleractinian recruits per m-2 for the 1-2cm and 2-5cm size classes around North West Mahé. ............................................................................ 9 Figure 2-3: Mean density of scleractinian recruits per m-2 for granitic and carbonate sites around North West Mahé. ........................................................................ ……10 Figure 2-4: Mean density of scleractinian recruits m-2 for shallow and deep sites around North West Mahé .................................................................................................... 11 Figure 2-5: Mean density of recruits within different scleractinian families around North West Mahé. ............................................................................................................. 12 Figure 2-6: Mean density of recruits within different scleractinian families for carbonate and granitic sites surveyed around North West Mahé ……………………………………..14
Figure 5-1: Mean Density of Holothurians around North West Mahé. ............................ 24 Figure 7-1: Mean density of scleractinian recruits per m-2 around Curieuse and Praslin ................................................................................................................................ 29 Figure 7-2: Mean density of scleractinian recruits per m-2 for the 1-2cm and 2-5cm size classes around Curieuse and Praslin ...................................................................... 30 Figure 7-3: Mean density of scleractinian recruits per m-2 for granitic and carbonate sites around Curieuse and Praslin .................................................................................. 31 Figure 7-4: Mean density of scleractinian recruits m-2 for shallow and deep sites around Curieuse and Praslin ............................................................................................... 32 Figure 7-5: Mean density of recruits within different scleractinian families at Carbonate Granitic sites around Curieuse and Praslin. ............................................................ 33
List of Tables Table 2-1: Sites across North West Mahe surveyed by GVI …………………………..…..6 Table 2-2: Total and mean density (m-2) of invertebrates recorded along the belt transects at all of the 21 sites surveyed around North West Mahé. .............. …Error! Bookmark not defined.
© Global Vision International – 2008
Executive Summary GVI have now completed the 17th 10-week phase of the Marine Conservation and Research Expedition in the Seychelles.
The expedition has maintained working
relationships with local schools and the community through local capacity building and community events. The expedition has continued to gather important environmental scientific data whilst working with local and national partners. The following activities were completed by GVI from July-September 2008:
Coral Recruitment surveying for 20 sites around North West Mahé on behalf of the Seychelles Centre for Marine Research and Technology – Marine Parks Authority (SCMRT-MPA).
In water surveys of the Endangered’ green turtle (Chelonia mydas) and the ‘Critically Endangered’ hawksbill turtle (Eretmochelys imbricata) in the Baie Ternay Marine Reserve, including focal behavioural studies on dietary preference for the latter, on behalf of the Turtle Action Group Seychelles (TAGS).
Fisheries surveys and recorded incidental sightings of lobster, octopus, and sea cucumbers for the Seychelles Fishing Authority (SFA).
Plankton monitoring on a weekly basis in addition to detailed identification records of all incidental Whale Shark (Rhincodon typus) sightings for inclusion in the international R.typus identification database EcOcean.
Incidental sightings of cetaceans and other mega fauna in the area on behalf of MCSS.
The running of a successful satellite camp on Curieuse Island, continuing inwater marine turtle surveys and a mark-recapture tagging programme for E.imbricata
Coral Recruitment surveying for 5 sites around Curieuse Island with a view to expanding GVI’s conservation and monitoring programme in the Seychelles Inner Islands on behalf of SCMRT-MPA.
Continuation of local capacity building and community awareness through the lessons with the Seychelles International School, the National Scholarship Programme and SCMRT-MPA Youth Dive Club.
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1. Introduction Global Vision International’s (GVI) Seychelles expedition is based on Mahé Island at Cap Ternay Research Centre, which is run by the Seychelles Centre for Marine Research and Technology – Marine Parks Authority (SCMRT-MPA). A satellite camp has been established on Curieuse Island just north of Praslin Island.
GVI’s main
partners are the SCMRT-MPA, and additional local partners include the Marine Conservation Society Seychelles (MCSS), and the Seychelles Fishing Authority (SFA). Expedition Members are trained by local and international personnel to conduct research on behalf of the local partners and in support of their ongoing work. This report summarizes the science and local capacity building programmes conducted during the ten weeks of the seventeenth expedition run at the base at Cap Ternay, Mahé and on Curieuse Island, from 11th July 2008 to 21st Septmeber 2008.
Background All of GVI’s scientific work in the Seychelles is carried out on behalf of our local partners and at their request, using their methodology. GVI supplies experienced staff, trained volunteers and equipment to help them achieve their aims. GVI currently has 4 partners, 2 governmental and 2 non-governmental, described overleaf.
Seychelles Centre for Marine Research and Technology – Marine Parks Authority (SCMRT-MPA): A local para-statal organization partly funded by government, with the aims of carrying out marine research in the Seychelles and protecting the marine parks. The coral and fish monitoring carried out for SCMRT-MPA constitutes the majority of the work conducted by the Expedition Members. Expedition Members also work alongside MPA rangers on the satellite camp located on Curieuse Island.
Marine Conservation Society Seychelles (MCSS):
A local NGO that carries out
environmental research in the Seychelles, currently monitoring Whale Sharks, cetaceans and turtles around Mahé. GVI assists with all three of these research programmes by reporting incidental sightings, conducting in-water juvenile turtle surveys, nesting turtle surveys and undertaking the weekly Plankton monitoring tows.
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Seychelles Fishing Authority (SFA): This is the governing body which oversees the management and regulation of commercial and artisanal fisheries in the Seychelles. This government agency is directly concerned with setting the catch, bag and seasonal limits that apply to local stocks on an annual basis, as well as managing the international export industry that is generated from the harvest of fisheries across the Seychelles Exclusive Economic Zone (EEZ).
Turtle Action Group Seychelles (TAGS): A local NGO with a board of directors that represents the interests of all stakeholders involved in marine turtle monitoring throughout the Seychelles. The purpose of this organisation is to enhance connectivity between conservation groups and create a region wide database to share information that will ultimately lead to greater awareness, and more effective region-wide management, of sea turtle populations.
Expedition Training All Expedition Members receive 2 to 3 weeks intensive training on arrival at Cap Ternay, and ongoing training and education throughout the volunteer phase by experienced staff members.
Dive Training: All Expedition Members must be at least PADI Open Water to join the expedition. Expedition Members then receive the PADI Advanced Open Water course covering Boat, Peak Performance Buoyancy, Navigation, Underwater Naturalist, and Deep dives. This is offered to all Expedition Members regardless of their qualification as they will require perfect buoyancy and navigation skills to complete the surveys successfully without harm to the environment they are surveying.
Species Identification Training:
Expedition Members are required to learn either
corals or fish on the species list, dependent on the methodology employed during the particular phase. Training is two-tiered, initially provided in the form of presentations, workshops, and informal discussion with the expedition staff. The materials necessary for self study are also available. A basic level of competence is tested using a slide show on land, for which a 95% pass mark is required. Expedition Members are then taken on coral and fish identification dives with staff members and ultimately tested underwater, requiring a 100% pass to guarantee competence to survey. A similar format
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is followed when Expedition Members are trained to identify the invertebrates and sessile communities that are also monitored.
Survey Methodology Training: After the Advanced Open Water course, Expedition Members are given further in-water training in the skills required to survey, with all participants completing the PADI Coral Reef Research Diver course.
This further
training includes the use of a delayed surface marker buoy, practice monitoring, and participation in monitoring dives in which they are supervised by a member of staff, ensuring the accuracy of the data recorded and consistency of monitoring techniques.
Health and Safety: The safety of all Expedition Members is paramount to the work of GVI and continuation of the Seychelles expedition. All EM’s are given a health and safety brief on the camp as soon as they arrive and conservative diving guidelines are set and adhered to for the duration of the expedition. In addition, Expedition Members complete the PADI Emergency First Response first aid course, and are taught how to administer Oxygen in the event of a diving related incident.
As a complement to the components outlined above a short series of lectures is given on the marine environment, including basic oceanography, coral reef biology, the importance of marine research and the threats posed by natural and anthropogenic disturbance. Additionally, scientists from various organisations make guest lectures on their research.
2. Coral Recruitment Introduction In 1998, a worldwide coral bleaching event decimated much of the coral surrounding the inner granitic islands of the Seychelles, with hard coral mortality reaching 95% in some areas (see Spencer et al, 2000). It is thought that this was precipitated by the high ocean temperatures associated with an El Nino Southern Oscillation event at that time. Efforts to monitor the regeneration of reefs in the Seychelles were initiated as part of the Shoals of Capricorn, a three year programme started in 1998 and funded by the Royal Geographic Society in conjunction with the Royal Society. The SCMRT was set up by the Shoals of Capricorn in an effort to ensure continuation of the work started, as well as
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manage, with the MPA, the existent marine parks.
A predominant focus for the
Seychelles GVI expedition is to aid this monitoring programme and thereby assist in the construction of management plans that will benefit the future recovery of coral reefs in the area.
Between the end of the Shoals of Capricorn programme in 2001, and 2004, when the GVI expedition was set up, monitoring efforts were continued by Reefcare International, a non-governmental organisation based in Australia.
The protocols established by
Reefcare International provided a foundation for those adopted by GVI, differing only in the more thorough taxonomic criteria adopted by the latter, and logistical constraints that restrict GVI’s monitoring efforts to the North west coast of Mahé Island.
The data collection conducted by GVI-trained Expedition Members contributes to a longterm monitoring programme that has now been in progress for ten years. By providing this support to the SCMRT-MPA, it is hoped that their capacity to monitor, manage and ultimately conserve the reefs of the Seychelles during this fragile period of regeneration will be greatly enhanced.
The coral recruitment programme looks at the diversity and density of both hard, scleractinian coral recruits and specified invertebrates. Aims •
To monitor the coral reefs at 20 various sites around North West Mahé. 16 of the sites are surveyed on a bi-annual basis, with a further four surveyed annually. From the 20 sites in total, ten are carbonate and ten are granitic, and they describe varying degrees of exposure to waves and current. Accordingly there are eight each of carbonate and granitic bi-annual sites, and two each of carbonate and granitic annual sites. GVI uses the methodologies described here to survey all 16 bi-annual sites, and two of the annual sites (N.B. selection of the latter is decided by GVI’s local working partners). Therefore, GVI aims to survey a minimum of 18 sites per ten week phase.
•
To estimate the density and diversity of juvenile coral genera.
•
To measure the impact of predation and algal grazing on coral recruitment through abundance estimates of hard coral predators and sea urchins.
To build upon existing data from previous research in the Seychelles in order to
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allow comparison with earlier survey data and to ascertain recent trends in coral reef recovery since the mass bleaching event of 1998.
Methods The expeditions vary between Coral Recruitment Surveying phase and methodologies and a Coral Reef Monitoring phase and methodology. The Seychelles 083 Expedition was used for recruitment methodologies, which are described in the following pages. Using SCUBA research survey teams, all the survey sites listed below were successfully surveyed during this phase.
Table 2-1: Study sites surveyed by GVI from July 11th to September 19th 2008.
Site
Substrate type
Survey frequency
Site #
Anse Major Reef
Carbonate
Bi-annual
13a
Baie Ternay Reef Centre
Carbonate
Bi-annual
9
Baie Ternay Reef North East
Carbonate
Bi-annual
8
Baie Ternay Reef North West
Carbonate
Bi-annual
10
Conception Central East Face
Carbonate
Bi-annual
2
Port Launay South Reef
Carbonate
Bi-annual
5
Therese North East
Carbonate
Bi-annual
22
White Villa Reef
Carbonate
Bi-annual
17
Corsaire Reef
Carbonate
Bi-annual
16
Willie’s Bay Reef
Carbonate
Annual
12a
Port Launay West Rocks
Granitic
Bi-annual
4
Site X
Granitic
Bi-annual
24
Site Y
Granitic
Bi-annual
19
Therese North End
Granitic
Bi-annual
21
Whale Rock
Granitic
Bi-annual
14
Conception North Point
Granitic
Bi-annual
1
Willie’s Bay Point
Granitic
Bi-annual
12b
Therese South
Granitic
Annual
23
Baie Ternay Lighthouse
Granitic
Additional
7
All GVI staff and Expedition Members who conducted the surveys were required to learn all corals on the target species lists. A basic level of competence is tested using a PowerPoint presentation, for which a 95% pass mark is required. Expedition Members
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are then taken on coral identification dives with staff members and ultimately examined underwater. A similar format is followed when Expedition Members are trained and examined in target invertebrates, and fisheries (sea cucumbers, octopus and lobster) identification prior to participating in the relevant surveys.
In summary, prior to data being included in the coral monitoring database Expedition Members must be able to achieve 95 % accuracy in a theory exam and 100 % accuracy in situ for all relevant target species/genera.
Fourteen different Hard Coral families were surveyed and within those, 47 different genera (these were not recorded down to species level as all identification of corals is done in situ and considered to be impossible to record accurately to this level in situ). Nine coral recruitment predators and one additional invertebrate, the Giant Clam (Tridacna sp.), were surveyed for SCMRT-MPA. The fisheries data GVI records includes 11 different groups of sea cucumbers (seven down to species, four to genus), octopus (Octopodidae spp), and two different genera of lobster. All target species lists for coral, invertebrates, and fisheries species (sea cucumbers, octopus and lobster) can be found in Appendices A, B and C respectively.
2.3.1
Hard Coral Recruitment Quadrates
The capacity for reef regeneration at the survey sites around North West Mahé was measured by estimating the density of recently recruited scleractinian corals, defined as any coral 1-5cm in diameter. At each site, density of the different coral genera was estimated by counting the number of recruits in a minimum of 30 1m2 quadrates: at least 15 “deep” quadrates at a depth of 5.1 to 10.0 metres and at least 15 “shallow” quadrates at a depth of 1.5 to 5.0 metres. The depths were standardized by chart datum. To ensure adequate coverage of the reef, quadrates were placed on the substrate in a haphazard fashion, in accordance with the protocol set out by Reefcare International.
2.3.2
Coral Predation and Algal Grazing Belt Transects
The extent of hard coral predation was measured as the density of invertebrate hard coral predators at each survey site, namely Drupella spp. of sea snail, the Cushion Star (Culcita spp.) and Crown of Thorns Starfish (Acanthaster planci). Two 50m transects were laid at oblique angles to the reef to cover the depth range of that site and to ensure part of the tape fell within both the “deep” and “shallow” quadrate zones. These depths
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were also standardized by chart datum. Target species falling within 2.5m either side of the tape were recorded. To monitor algal grazing pressure, the density of sea urchins was simultaneously recorded.
Results Scleractinian Recruit Density Mean recruit density, calculated across all the monitored sites, for the July-September 2008 survey period was 14.51m-2 ±0.37SE (Figure 2-1). There appears to have been an increase in recruit density over time from August-September 2005 where recruit density was 5.38m-2, ±0.31SE, there was however, a drop in recruit density from July– September 2007, where there were 9.56m-2 ±0.29SE. 16
14
Recruit Density m-2 (+/-SE)
12
10
8
6
4
2
0 Engelhardt 2002
n=767
n=626
n=658
n=596
n=651
n=641
n=670
Aug-Sept 05
Jan-Mar 06
July-Sept 06
Jan-Mar 07
July-Sept 07
Jan-Mar 08
July-Sept 08
Survey Period
Figure 2-1: Mean density of scleractinian recruits per m-2 (±SE) of the 1-5cm size class over time, for sites surveyed around North West Mahé (n= number of quadrates, 24 sites were surveyed in AugSept05, 18 sites were surveyed in Jan-Mar 06, July-Sept 06, Jan-Mar 07 and July-Sept 07 and 19 sites were surveyed in Jan-Mar 08).
This data reflects an overall increase in mean coral recruit density since previous research undertaken utilising the same methodology in 2002 (Engelhardt, 2003), when mean scleractinian recruit density was 7.47m-2. Differences in the mean recruitment levels from 2002 to 2005 may have been related to differences in the number of sites
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surveyed between studies. GVI monitors 24 sites across North West Mahé (as described in Engelhardt, 2003) but does not include the additional 24 sites surveyed in 2002 on Mahé East which have been shown to possess less diverse and abundant Scleractinian populations Engelhardt (2003). In addition, significantly greater numbers of recruits have been recorded for the Jan-March sampling periods.
Size Class Comparisons Coral recruits were divided into two categories based upon their size; 1–2cm and 2– 5cm. The mean recruit density was greater in the 2-5cm size class than that measured for the 1-2cm size class in the 2008 survey period (7.58m-2 ±0.15SE and 6.09m-2 ±0.16SE, respectively), (Figure 2-2). The lower values for coral recruitment in the 1-2cm size class are consistent over time and correspond to previous studies in the area (Engelhardt, 2003).
9
n=1343
8
n=1247
7
n=1343
-2
Recruit Density m (+/-SE)
n=1284
6
5
4
n=767
n=1284
n=1247
3
2 n=767
1
1-2cm 2-5cm
0 2005
2006
2007
2008
Survey Period
Figure 2-2: Mean density of scleractinian recruits per m-2 (±SE) for the 1-2cm and 2-5cm size classes over time, for all surveyed sites around North West Mahé (n=number of quadrates, 24 sites were surveyed in Aug-Sept 05, 18 sites were surveyed in Jan-Mar 06, July-Sept 06, Jan-Mar 07 and JulySept 2007 and 19 sites were survey in Jan-Mar 08). Data has been pooled for years.
The overall increase in mean recruit density over time is predominantly driven by a logarithmic increase in density of the 2-5cm size class, from 3.52m-2 (±0.10SE) in August-September 2005, to 8.4m-2 (±0.22SE) in July-September 2008.
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density of the 1-2cm size class has however, increased more than three-fold between Aug-Sept 05 (1.86m-2 ±0.08SE) and July-September 2008 (6.13 m-2 ±0.21SE).
2.4.3 Reef Substrate Comparison A comparison was made between mean scleractinian recruit density on granitic and carbonate reef habitats.
During all survey periods higher recruit densities were
supported on granitic reefs compared with carbonate sites (Figure 2-3). The recruit density at granitic sites increased almost three-fold from 5.92m-2 ±0.22SE in 2005 to 15.37m-2 ±0.24SE in 2008. The recruits on carbonate sites started at a similar density to that of Granitic 4.75m-2 ±0.19SE in 2005 but increased to a much lower density of 11.57m-2 ±0.35SE in 2008 (Figure 2-3). 18
n=309
16
n=640
14
Recruit Density m-2 (+/-SE)
n=563
12 n=332
10
8
n=687 n=480
n=607
n=448
6 n=240
4
n=353
2
Granitic Carbonate
0 Engelhardt 2001
2005
2006
2007
2008
Survey Period
Figure 2-3: Mean density of scleractinian recruits per m-2 (±SE) for the 1-5cm size class over time, for granitic and carbonate sites around North West Mahé (n=number of quadrates, 24 sites were surveyed in Aug-Sept 05, 18 sites were surveyed in Jan-Mar 06, July-Sept 06, Jan-Mar 07 and JulySept 07 and 19 sites were surveyed in Jan-Mar 08). Data has been pooled for years.
2.4.4 Depth Comparison A comparison was also made between mean recruit density recorded in shallow (1.55.0m) and deep (5.1-10.0m) zones at the monitoring sites. Recruitment rates have been consistently higher between 5.1 and 10.0m for all the surveys carried out to date. The
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recent 2008 survey period follows this trend with 12.5m-2 ±0.36SE recruits for shallow quadrates and 14.76m-2 ±0.39SE for deep quadrates (Figure 2-4).
16 n=671
14 n=613 n=617
Recruit Density m-2 (+/-SE)
12
n=672
10 n=634 n=667
8 n=391
6
n=376
4
2 Shallow Deep
0 2005
2006
2007
2008
Survey Period
Figure 2-4: Mean density of scleractinian recruits m-2 (±SE) in the 1-5cm size class over time, for shallow (1.5–5.0m) and deep (5.1–10.0m) sites around North West Mahé (n= number of quadrates, 24 sites were surveyed in Aug-Sept 05, 18 sites were surveyed in Jan-Mar 06, July-Sept 06, Jan-Mar 07 and July-Sept 07 and 19 sites were surveyed in Jan-Mar 08). Data has been pooled for years.
2.4.5 Family Specific Diversity Genus and family of individual recruits were recorded, and comparisons made of mean recruit density at family level, over time. Data has been pooled yearly. Faviidae and Poritidae populations supported the highest densities of recruits (4.63m-2 ±0.14SE and 2.83m-2 ±0.1SE respectively, in 2008), (Figure 2-5). Faviidae, Poritidae and Acroporidae families showed the highest increase in recruit density since monitoring started in 2005, with the Acroporidae recruit population increasing five-fold from 0.41m-2 ±0.04SE in August-September 2005 to 2.1m-2 ±0.09SE in July-September 2008.
Figure 2-6 displays the recruit densities of Faviidae, Poritidae, Acroporidae and Pocilloporidae families compared to all other families combined, at both carbonate and
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granitic sites. At carbonate sites all scleractinian families showed a significant increase from 2005 to 2006, after which the increase in recruit density is driven Acroporidae, Pocilloporidae and all other families. A similar pattern is seen at granitic sites where there is a high increase in Faviidae and Poritidae recruits between 2005 and 2006, after which there is an a more gradual but constant increase in Acroporidae, Pocilloporidae and all other families.
2005
6
2006
Recruit Density m-2 (+/-SE)
2007
5
2008
4
3
2
1
As iid tro ae co en iid ae O cu De lin nd id ae ro ph yl lii da Un e id en tif ie M d er ul in id ae Pe ct in iid ae Eu ph yl lid ae
ae
ng Fu
e id a
us si d M
ae
ra st re
ric iid
Si de
or op
Ag a
id ae
id ae or ci ll Po
rit
op Ac r
Po
Fa vi id
ae
id ae
0
Scleractinian Family
Figure 2-5: Mean density of recruits within different scleractinian families (±SE) in the 1-5cm size class over time, for all sites surveyed around North West Mahé (24 sites were surveyed in Aug-Sept 05, 18 sites were surveyed in Jan-Mar 06, July-Sept 06, Jan-Mar 07 and July-Sept 07 and 19 sites were surveyed in Jan-Mar 08). Data has been pooled for years.
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All Other Corals
16
Pocilloporidae Acroporidae
14
Poritidae
Recruit density m2
12
Faviidae
10 8 6 4 2 Carbonate
Granitic
Carbonate
Granitic
Carbonate
Granitic
Carbonate
Granitic
0 2005
2006
2007
2008
Survey period
Figure 2-6: Mean density of recruits within different scleractinian families (±SE) in the 1-5cm size class over time, for carbonate and granitic sites surveyed around North West Mahé (24 sites were surveyed in Aug-Sept 05, 18 sites were surveyed in Jan-Mar 06, July-Sept 06, Jan-Mar 07 and JulySept 07 and 19 sites were surveyed in Jan-Mar 08). Data has been pooled for years.
2.4.6 Coral Predator and Algal Grazing Invertebrate Belt Transects Echinothrix sp. exhibited the highest mean density of the coral recruitment predators and algal grazers monitored (0.43m-2) (Table 1). A density of 0.33m-2 Diadema sp. was also recorded. Previous research has shown that the extent of algal grazing pressure by urchins can impact the rate of coral recruitment (Engelhardt, 2004). Future analysis, able to encompass data collected over a long time period, will be able to investigate and potentially corroborate this finding.
Actual coral recruit predators had low levels of
prevalence, with only 199 Drupella sp., 38 Culcita sp., and 2 Acanthaster planci found across all 21 monitored sites (Table 1). Coral predator and algal grazing invertebrate populations appear to be stable, as these numbers are similar to past phases.
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Table 2-2: Total and mean density (m-2) of invertebrates recorded along the belt transects at all of the 19 sites surveyed around North West Mahé.
Species
Diadema sp. Echinothrix sp.
Common name
Long spine sea urchin
Total
Mean
Number
Density
Recorded
m-2
3414
0.33
4543
0.43
Short spine sea urchin
Pencil spp.
Pencil urchin
241
0.0229
Toxopneustes pileolus
Flower urchin
14
0.0013
Cake spp.
Cake urchin
0
0
Echinometra sp.
Mathae’s sea urchin
42
0.004
Other sea urchins
0
0
Drupella sp.
Drupella shells
199
0.0189
Culcita sp.
Cushion Star
38
0.0036
2
0.0002
Other starfish
128
0.0122
Giant Clams
19
0.0018
Acanthaster planci
Tridacna sp.
Crown of Thorns starfish
Discussion The mean density of recruits for the monitored sites increased at the start of GVI’s monitoring in August-September 2005 until July-September 2008. The apparent fall in recruit density between 2002 and August-September 2005 may be due to minor bleaching events that occurred in April 2002 (Wendling et al. 2002) and 2004 (Payet et al, 2005), and the December 2004 Tsunami (Engelhardt 2008, Pers. Comm), that potentially suppressed fecundity rates of local populations in the interim.
There appear to be fluctuations in the abundance of recruits with the January-March survey periods displaying a larger increase and July-September survey periods showing a more marginal or even a decrease in recruit density. The greater abundance of recruits is indicative of seasonal fluctuations in reproductive output which are consistent with
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Wallace’s (1985) findings on the annual broadcast spawning of many Scleractinians across the Great Barrier Reef. Broadcast spawners such as the abundant Acroporids, participate in the mass annual gamete release in November and December in the Southern hemisphere (Engelhardt, 2005). The recruitment and growth of such corals may coincide with the higher appearance of 1-5cm recruits during the early survey periods.
A number of trends which were highlighted by the previous survey periods as well as by research conducted prior to the initiation of GVI’s monitoring programme, have continued; greater mean densities of recruits were found at both granitic sites and deep zones, compared to carbonate sites and shallow zones. A significant proportion of the scleractinian recruit population is contributed by the Faviidae and Poritidae families. The large initial recruit increase of these two families could be attributed to their reliance to the coral bleaching events of the Seychelles (Goreau, 1998).
The almost entire
elimination of other dominant families including Acroporids and Pocilloporids after the 1998 bleaching event (Goreau, 1998; Engelhardt, 2002), would have greatly reduced competition to Faviidae and poritidae recruitment. However, the fast growing Acroporids and Pocilloporids are also showing a good recovery after a lag in recruitment. Because the branching forms of these corals create complex environments for other reef organisms including fish and invertebrates, the abundance of these family’s recruits can be used as an indication of the health of coral reefs. Additional surveys to be conducted in the early part of 2009 will provide a clearer picture of these trends over time.
Further studies should be undertaken to observe what effects, if any, the high numbers of grazing sea urchins is having on coral recruits. At this time, actual coral predator numbers are very low over the 21 sites.
3. Turtle Monitoring Introduction Five species of marine turtles are found in the Seychelles: the Leatherback (Dermochelys coriacea), Loggerhead (Caretta caretta), Olive Ridley (Lepidochelys olivacea), and Hawksbill (Eretmochelys imbricata), and Green (Chelonia mydas) turtles. The Leatherback, Loggerhead and Olive Ridley, although common in the Western Indian
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Ocean, are not thought to currently nest in the Seychelles and are rarely seen. In contrast, the Hawksbill and Green are resident in coastal waters of the Seychelles, nest on the beaches, and are commonly observed. All five species found in the Seychelles face the combined threats of poaching, pollution and loss of nesting sites, and are listed by the World Conservation Union (IUCN) as endangered or critically endangered. The Seychelles is considered one of the most important sites for the critically endangered Hawksbill turtle (CITES) and represents one of the only localities in the world where E.imbricata can be observed nesting during the daylight hours.
Detailed research into the biology and migratory behaviour of sea turtle populations is currently conducted in Australia and the Indo-Pacific region. In the Seychelles, there are several monitoring programmes also underway. GVI’s turtle monitoring is undertaken on behalf of Seychelles Centre for Marine Research and Technology – Marine Parks Authority, the Marine Conservation Society Seychelles (MCSS) and Turtle Action Group of Seychelles (TAGS) to provide data for a region wide conservation database. Furthermore, local partners also conduct their own research in the form of in-water turtle surveys to study the abundance of resident adolescent turtles in their foraging territories and beach surveys to monitor the behaviour and success of nesting females.
GVI is involved in both types of turtle monitoring around North West Mahé; beach patrols for nesting turtles are conducted during the nesting season (October-March) and inwater surveys for resident turtles are conducted year round. In addition to the specified monitoring, all incidental turtle sightings, recorded whilst on dives, snorkels, and surface sightings from the boat, are recorded all year round.
GVI’s previous turtle census methodology incorporated U-shaped transects and point counts as a means to gauge seasonal fluctuations in the resident population of sea turtles within Baie Ternay, however preliminary results from research conducted by von Brandis in the Amirantes established that philopatric behaviour is common among foraging hawksbill turtles, and extensive information on individuals and their energy budgets can be gathered using relatively non-invasive sampling protocols (R. von Brandis 2008, Pers. Comm.). With the assistance of local partners, GVI has introduced a more comprehensive methodology to draw specific conclusions on the identification of individuals within the marine reserve and their foraging ecology.
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Focal behavioural studies work on the philosophy that an individual, when followed and observed correctly, can provide a wealth of ecological information that would otherwise be unnoticed in a simple point count survey. Our objective is to document important interactions between hawksbill turtles and their environment while obtaining information of prey preference and the number of individuals displaying site fidelity within the Baie Ternay Marine Reserve.
The specific aims for the project are as follows:
i.
To determine the constituents and preferred food items of hawksbill turtle diets in the Baie Ternay Marine Reserve;
ii.
To identify resident individuals displaying philopatric behaviour in the confines of Baie Ternay;
iii.
To provide further information on the energy budgets of E. imbricata.
3.2 Overall aims of GVI’s marine turtle monitoring program •
To continue monitoring marine turtles on behalf of SCMRT-MPA, MCSS and TAGS.
•
To continue twice weekly in-water focal behavioural SCUBA surveys for resident turtles in the Baie Ternay Marine Park.
•
To continue collecting nesting turtle data on three beaches around North West Mahé, Grand Anse, Anse Du Riz and Anse Major and on Curieuse Island National Park.
This is to be undertaken during Hawksbill nesting season,
October through March. •
To continue recording all incidental turtle sightings.
•
To help the SCMRT-MPA, MCSS and TAGS raise public awareness of the status of the five species of marine turtles in Seychelles.
3.3 Methods 3.3.1 In-Water Surveys GVI staff and Expedition Members are trained in turtle identification through lectures and PowerPoint presentation in which they learn to ID both from seeing the turtle and also
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from the tracks. All are also trained in the necessary survey techniques, thus allowing them to participate in both the water based and land based surveys.
Focal Behavioural Studies: Expedition members will use SCUBA equipment to undertake a U-shaped search pattern on the same bearings previously utilised for ‘turtle snorkel’ methodology. Divers look for focal animals in buddy pairs and, upon finding an individual, follow and document all behaviours observed. Environmental conditions can dictate at what distance accurate observations are made without altering normal behaviour but in general a distance of no closer than 5 metres is required.
A continuous time scale of data is used, i.e. divers will stay with any individual encountered for as long as possible even if another individual is located. In the event that another turtle is found, the second member of the buddy pair may start to document behaviour but at no time are buddy pairs to become separated by more than 2 metres. Any characteristic markings should be documented and the use of underwater photography is highly desirable for turtle identification and determining unknown prey items.
Incidental Turtle Sightings:
For every dive undertaken by GVI, a record of turtle
observations is kept. The parameters for each of GVI’s dives were logged, regardless of whether a turtle was seen, enabling the calculation of turtle frequency per dive and thus effort-related abundance. In addition to the dive data, incidental sightings included inwater, non-survey snorkels and surface observations from the boat. The species, sex, size and behaviour of all turtles sighted was recorded wherever possible.
3.3.2
Beach Surveys
Nesting Turtle Monitoring Project: Beach patrols are conducted on North West Mahé during the hawksbill turtle nesting season (October to March). This land-based turtle monitoring work includes beach walks, the documentation of nesting tracks, and investigation of newly hatched clutches. Beach patrols are carried out weekly at specific beaches local to the research station (Anse Du Riz, Grand Anse and Anse Major) to monitor nesting turtle activity. The surveys are conducted on foot, with the survey teams walking along the upper beach searching for signs of tracks or body pits, on the main beach, and also within the coastal vegetation. The patrols were carried out on a weekly
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basis and so it was important to carefully study the beach for signs of activities that may have been partially erased by tides. The patrols and any observations were recorded using the standard MCSS beach patrol form.
3.4 Results 3.4.1 In-Water Surveys
Incidental Turtle Sightings: Out of the 138 dives completed this phase, 22 turtles were observed, which accounts to sightings on 13% of dives. Of those 22, 15 were Hawksbill and 7 were Green turtles. In addition to turtles seen on dives, 31 others were observed from the boat and non-survey snorkels. 18 of these were identified as Hawksbills, and the remaining 7 as Green turtles (Chelonia mydas), 6 unidentified.
Focal Behavioural Study: During turtle focal behaviour dives there were 26 turtles studied all of which were Hawksbills, although there were no observations of feeding.
3.4.2 Beach Surveys No beach surveys were completed this phase as it is outside of the Hawksbill nesting season.
3.5 Discussion The numbers of turtles sighted incidentally by GVI divers was 22 this phase – this supports the need in North West Mahé to continue ongoing monitoring of feeding and breeding populations in the area.
Preliminary evaluations of our newly trialed focal
behavioral study have been promising. The number of turtles found and observed throughout the course of this phase suggests that there is scope for long-term incorporation into the annual monitoring program. A large amount of ecological information can be obtained using this methodology and it is far less obtrusive than other means of dietary analysis, such as gut content analysis, which are commonly employed in the field. Nesting studies are expected to commence again from October until March thereby coinciding with the Hawksbill turtle breeding season.
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Even though no foraging was recorded of the 26 turtles that were followed, an increasing level of habituation to divers has been evident (Pers. Obs.), and further sampling is probably necessary before the natural feeding behaviours can be observed in situ (von Brandis, R. pers. comm..).
Turtles were sighted on 15% of all dives, 68% of which were identified as E. imbricata. This information highlights the important ecological role that North West Mahe has for the future success of critically endangered hawksbill populations within the Seychelles, a finding supported by the results of previous studies conducted by Haughton et al (2003) and GVI. With the impending construction of a large scale development on the Baie Ternay marine park site, determining preferred prey items is more important than ever as a mechanism for monitoring potentially adverse changes to the benthic community. The creation of a marine park database for the accurate identification of individuals displaying philopatric behaviour is also recommended for the future.
4. Whale Shark and Plankton Monitoring Introduction The Seychelles is famous for its seasonal fluctuations in the abundance of Whale Sharks (Rhincodon typus). However, despite their public profile, relatively little is known about their behaviour or the ecological factors which influence their migratory patterns.
A Whale Shark monitoring programme was started by volunteers in 1996 and is now the cornerstone of a lucrative eco-tourism operation run by the MCSS. The MCSS has been a key advocate of elevating the profile and status of R.typus, and protecting them within Seychelles waters.
However, the effectiveness of this initiative is limited by our
understanding of Whale Shark biology, which is not adequate for making informed decisions on a regional approach to Whale Shark conservation and management. From 2001-2003, a tagging programme was initiated to study migratory patterns as part of the Seychelles Marine Ecosystem and Management Project (SEYMEMP), and it is now clear the sharks seen in the Seychelles are not residents, but range throughout the Indian Ocean. The oceanographic or biological conditions that determine the movements are unclear.
It is possible however that the sharks follow seasonal variations in the
abundance of plankton, on which they feed.
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MCSS initiated a plankton monitoring programme in conjunction with the tagging and incident recording surveys in an attempt to correlate the frequency of Whale Shark sightings with plankton levels. The plankton sampling has been run by MCSS since 2003, in conjunction with their ongoing Whale Shark monitoring and tagging programmes.
GVI started to assist MCSS in the collection of plankton data in July 2004, and have since carried out the survey on a weekly basis. In addition, GVI also makes incidental recordings of whale sharks which include digital photographs for inclusion on the EcOcean identification database. Aims •
To continue recording incidental Whale Shark sightings and to provide the data to MCSS.
•
To continue the weekly plankton sampling programme at Grouper Point.
•
To provide digital photographs for Indian Ocean wide R.typus identification.
Methods GVI staff and Expedition Members are trained in the observational and recording techniques required to collect data for both the Incidental Whale Shark Sightings and the Plankton Monitoring Survey, in accordance with MCSS’s formal specimen sampling and recording procedures.
Incidental Whale Shark Sightings: When a Whale Shark is sighted, as much information as possible is recorded, by the boat driver and snorkellers or divers as appropriate.
The time, date, GPS, number of animals, size of the individuals, sex,
distinguishing features, behaviour and tag numbers if present are recorded. Photographs are also taken whenever possible of the left and right side of the thorax from the base of the pectoral fin to behind the gill area.
Plankton Sampling: Once every week, on a Wednesday, 5 plankton sample tows are carried out to the North Western side of Grouper Point, just outside of Cap Ternay Marine Park, between the hours of 09:00 hrs and 11:00hrs.
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The tows are carried out along a north-westerly course heading from Grouper Point out to sea. In order to sample over a range of depths, the net is let out a further 5m every 30 seconds (up to 45 metres).
Samples are collected in the ‘cod end’ of the net,
decanted into a receptacle and preserved in formalin.
After the survey and the filtering process, they are passed to MCSS for measurement of wet weight and classification of species. Environmental conditions are also noted (sea state, cloud cover and underwater visibility).
Results Over the 10 week expedition there has been one Whale Shark sighting from GVI’s research vessel. The plankton samples were passed to MCSS for analysis.
Discussion GVI will await the results of the plankton analysis from MCSS, to correlate plankton composition with presence/absence and abundance of Whale Sharks. Recording of incidental Whale Shark sightings and weekly plankton tows will continue.
5. Fisheries Assessment Introduction Lobster, octopus and sea cucumber monitoring has been incorporated into our coral recruitment surveying programme at the request of the Seychelles Fishing Authority, to assist in their wider ranging research programmes. This data is handed to the SFA and will contribute to a large scale SFA sea cucumber monitoring programme, being carried out across the Seychelles. Aims •
To train Expedition Members in background biology and target species identification, together with relevant methodologies.
•
To record incidental sightings of octopus and lobster during all survey and recreational dives.
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•
To undertake sea cucumber, lobster, and octopus monitoring in conjunction with the coral reef research in support of an ongoing survey by the SFA.
Methods All GVI staff and Expedition Members who conducted the surveys were required to learn 11 different groups of sea cucumbers (7 down to species, 4 to genus), octopus (Octopodidae spp), and 2 different genera of lobster. A basic level of competence is tested using a PowerPoint presentation, for which a 95% pass mark is required. EM’s are then taken on identification dives with staff members and ultimately examined in situ underwater requiring a pass mark of 100% accuracy. The relevant target identification list is described below and show in full in Appendix C.
During the coral predator / algal grazer transects carried out to record target species density during coral recruitment monitoring surveys, one of the divers in the buddy pair recorded any sightings of lobster, sea cucumber, and octopus. The two transects at each site were 5m x 50m long. Incidental sightings of lobster and octopus are also recorded on all non-survey dives.
Results 5.4.1 Sea Cucumbers In total, 216 sea cucumbers were recorded, the most common of which was Pearsonothuria graeffei (mean density of 0.0084m-2 ±0.0095SE across 21 sites surveyed) (Figure 5-1). Stichopus sp., Bohadashia sp. and Holothuria artra were also well represented (mean density of 0.0059 m-2 ±0.0002SE, 0.0022 m-2 ±0.0046SE and 0.0019 m-2 ±0.0001SE and respectively). These four sea cucumber species are consistently the most abundant around the sites surveyed.
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0.009 * Commercial Species
Mean Density m-2 (+/-SE)
0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001
Pe
ar s
on
ot h
ur ia
gr ae St ffe ic ho i p Bo us ha sp ds . ch H ia ol sp ot hu . Ac ria ar tin tra op *T he yg a le *H no sp ol . t a ot an hu an ria as fu *H sc *H ol og ol ot ot hu ilv hu a r ia r ia *H no fu ol bi sc ot lis op hu ria un ct sp at .( Pe a Th nt el en ar d ) ot a an ax
0
Species
Figure 5-1: Mean Density of Holothurians (m-2 ±SE) around North West Mahé (21 sites, two transects were surveyed at each site).
5.4.2 Lobsters There were no lobsters observed during the surveyed transects. In total there were fourteen incidental sightings of lobsters on non-survey dives or whilst snorkelling. Thirteen of the lobster sightings were the Spiny Lobster (Panulirus spp) variety, while one was the slipper lobster (Parribacus caledonicus).
5.4.3 Octopus There were three octopus sighted during coral recruitment survey dives, and twenty one incidental sightings on non-survey dives or whilst snorkelling. All octopus sightings were of the Common Reef Octopus (Octopus cyanea).
Discussion All data from this survey has been passed to the Seychelles Fishing Authority for inclusion in their wider research programme. GVI will wait to receive the results of
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analysis from these data and will continue monitoring for these target species and genera.
6. Cetacean Sightings Introduction Cetaceans are frequently sighted from the boat within GVI’s area of operation. Cetaceans are considered to be under threat in many parts of the world and in response to this threat, a national database of cetacean sightings, The Seychelles Marine Mammal Observatory (SMMO), has been set up. GVI records all incidental cetacean sightings using the MCSS standard sighting form and pass all data to the MCSS for inclusion in the national database.
Aims •
To assist in the relative monitoring of the populations of cetaceans within coastal Seychelles waters.
•
To conserve the existing populations of cetaceans in Seychelles waters.
Methods GVI staff and Expedition Members were trained in the identification of cetaceans and were supplied with additional identification materials.
Incidental cetacean encounters were recorded using the standard MCSS Cetacean Sightings form. Data recorded included date, time, location, environmental conditions, abundance, distinguishing features, size, behaviour and species. Photographs were taken whenever possible to assist identification and contribute to a catalogue of individuals.
Results Cetaceans were recorded on fifteen separate occasions.
A minimum of nineteen
individuals were seen on these occasions. Only one species was positively identified,
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the Common Bottlenose dolphin (Tursiops truncatus), which accounted for 100% of all recordings.
Discussion Due to weather conditions, the low elevation of the survey vessel, and the distance at which most of the cetaceans are observed, it is a concern that positive identification will not always be obtained, as has been the case in previous survey periods.
It is
suggested that the skills and experience of identifying cetaceans in situ may also be limited due to the range of subjects the trained volunteers have to master in a short period of time. The results prove the presence of this species in the coastal waters of North West Mahé, but if additional focus is sought in the area of research through GVI's resources then a reduction in focus elsewhere may be necessary to give staff and Expedition Members additional time and experience with in situ cetacean identification.
7. Satellite Camps & Community Development Curieuse Island
7.1.1 Introduction Curieuse Island is situated to the North of Mahé, close to Praslin. The island and its surrounding waters are protected as National Terrestrial and Marine Park, and is only one of a few places on the planet where a population of Aldabra Giant tortoises lives freely. It is also one of only two places where the Coco-de-Mer, an endemic species, grows naturally.
The island and reserve serves as a major tourist attraction and
economic resource for the Seychelles, and also suffers from poaching of its resources.
Upon the island is the main Ranger Station for SCMRT-MPA, where the logistical operations of the reserve are based. In August of 2005, GVI established a small satellite camp on the island to work with SCMRT-MPA to develop a coral reef monitoring programme, in line with the research conducted by GVI on SCMRT-MPA’s behalf in North West Mahé, thus expanding the geographical range of the survey area.
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The intention is to use the programme for local capacity building. GVI and SCMRT-MPA will use the programme to create a skills exchange between the rangers, with their vast knowledge of the area and multitude of skills, and GVI staff and Expedition Members, with their knowledge of computers, databases, dive instruction, first aid skills, and knowledge of target identification for species and genera of the region.
A historical Leper colony is found on Curieuse Island. It is a shared vision of GVI and SCMRT-MPA to restore some of the old houses to their original state as part of a visitor’s attraction. At the beginning of 2007, GVI broke ground to begin expanding one of the old leper houses, in which GVI currently resides. This will enable a higher number of GVI personnel to be on the island at any one time, therefore allowing more man power for training and surveying purposes.
Coral Reef Monitoring and Coral Recruitment surveying was initiated around Curieuse and Praslin Islands in 2001 and continued until 2004 by Reefcare International. GVI has undertaken and hopes to expand and continue this monitoring programme during 2008, and beyond, on behalf of SCMRT-MPA.
Aims •
To continue a presence on Curieuse, sending six Expedition Members and two to three staff members to the island each week.
•
Complete extensions and improvements to GVI’s Curieuse house so the capacity of the marine research programme can be increased to 12 Expedition Members and the infrastructure improved to accommodate a larger diving programme.
•
To continue the skills exchange between the SCMRT-MPA and GVI.
•
To allow for immediate local capacity building on a scale larger than GVI's other initiatives feasibly allow.
•
To continue and expand the coral reef research programme on Curieuse by GVI.
•
To supply personnel to assist the rangers when need be, with anything from research programmes to manual labour.
•
To establish training sites to be used for local capacity building, GVI personnel and ranger training in the future.
•
To census and map Coco-de-Mer populations across the Island.
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Methods The house expansion continued this phase as GVI volunteers spent a total of 7 weeks on the island.
In addition to the renovation process, GVI was able to start a self
sufficient diving programme on the island in April 2007, with five marine sites being surveyed following the same Coral Reef Monitoring and Coral Recruitment methodology carried out on Mahé, detailed above in section 3.1. A record of all mega-fauna seen in the area was also recorded for all dives and snorkels.
Due to this monitoring programme still being in its infancy on Curieuse, it has not been determined as of yet how often sites will be monitored and which of the previously surveyed sites by Reefcare International will be feasible for GVI to undertake. Listed below are the five sites monitored by GVI this year.
Carbonate sites: Anse Petit Cours Coral Garden (It should be noted, due to the reef contours, it is only possible to complete deep quadrates and deep sections of the belt transects at this site.)
Granitic sites: Curieuse West Rock St Pierre East Rock Curieuse North Centre Rock
7.1.4 Results
7.1.4.1 Scleractinian Recruit Density Mean recruit density, calculated across all the monitored sites, for the July-September 2008 survey period was 11.64m-2 ±0.42SE. These data reflect a sustained increase in mean coral recruit density since previous research undertaken utilising the same methodology both in 2002 (Engelhardt, 2003), when mean scleractinian recruit density was 7.47m-2, and when GVI’s monitoring began in July-September 2007, where mean recruit density was 8.22m-2 ±0.35SE. This relates an increase in scleractinian coral recruit density, however it should be noted that GVI’s work on Curieuse – Praslin area was carried out over 5 sites during July-September 2007 and the present survey period, and 4 sites during January-March 08, whereas, the study undertaken by Engelhardt
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(2003) was carried out over a total of 48 sites around Mahé and on other islands. The Curieuse results represent a slightly lower mean recruit density than surveys carried out for this survey period around North West Mahé (14. 51m-2 ±0.37SE, Figure 2-1). Figure 7-1 shows the mean density m-2 for each site since monitoring began in July-September 2007. All sites except for Coral garden show a significant increase in recruit density from the first survey period. The carbonate site Anse Petit Cours shows the largest increase in recruit density from 7.47m-2 ±0.36SE in July-September 2007 to 6.76m-2 ±0.34SE in July-September 2008 (Figure 7.1). July-Sept 07
16
Jan-Mar 08 July-Sept 08
-2
Recruit Density m (+/-SE)
14 12 10 8 6 4
Curieuse North Center Rock
Curieuse West Rock
St Piere South East
Anse Petit Cours
n=17
n=20
n=18
n=30
n=30
n=30
n=31
n=30
n=31
n=31
n=33
n=30
n=31
0
n=30
2
Coral Garden
Site
Figure 7-1: Mean density of scleractinian recruits per m-2 (±SE) of the 1-5cm size class for all surveyed sites around Curieuse and Praslin (n= number of quadrates, 5 sites were surveyed in JulySeptember 2007 and July-September 2008, 4 sites in January-March 2008).
7.1.4.2 Size Class Comparisons Coral recruits were divided into two categories based upon their size: 1–2cm and 2– 5cm. The mean recruit density was greater in the 2-5cm size class than the 1-2cm size class in July-September 2008 (6.79m-2 ±0.28SE and 4.84m-2 ±0.22SE, respectively) (Figure 7-2).
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Recruit Density m -2 (+/-SE)
8 7 6 5 1-2cm
4
2-5cm
3 2 1 0
n=139 n=139
n=113 n=113
n=140 n=140
July-Sept 07
Jan-Mar 08
July-Sept 08
Survey Period
Figure 7-2: Mean density of scleractinian recruits per m-2 (±SE) for the 1-2cm and 2-5cm size classes for all surveyed sites around Curieuse and Praslin (n=number of quadrates, 5 sites were surveyed July-September 2007 and July-September 2008, 4 sites were surveyed in January-March 2008).
7.1.4.3 Reef Substrate Comparison A comparison was made between mean scleractinian recruit density on granitic and carbonate reef habitats. Surveys carried out over the last six survey periods around North West Mahé have shown consistently higher recruit densities on granitic substrate (Figure 2.3), whereas the sites around Curieuse and Praslin show no significant difference between habitats (Figure 7-3).
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Recruit Density m -2 (+/-SE)
14 12 10 8
Carbonate
6
Granitic
4 2 0
n=48
n=91
July-Sept 07
n=50
n=63
Jan-Mar 08
n=47
n=93
July-Sept 08
Survey Period
Figure 7-3: Mean density of scleractinian recruits per m-2 (±SE) for the 1-5cm size class, for granitic and carbonate sites around Curieuse and Praslin (n=number of quadrates, 5 sites were surveyed in July-September 2007 and July-September 2008, 4 were surveyed in January-March 2008).
7.1.4.4 Depth Comparison A comparison was also made between mean recruit density recorded in shallow (1.55.0m) and deep (5.1-10.0m) zones at the monitoring sites. Surveys carried out over the last six survey periods around North West Mahé have consistently found a higher recruit density in deep zones compared to shallow zones (Figure 2-4). During the first two survey periods around Curieuse and Praslin there was little difference in recruit density with depth, whereas there was a slightly higher density in the deep zones during the latest survey period, consistent with the data of North West Mahé (Figure 7-4).
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Recruit Density m -2 (+/-SE)
14 12 10 8
Deep
6
Shallow
4 2 0
n=78
n=61
July-Sept 07
n=65
n=48
Jan-Mar 08
n=78
n=62
July-Sept 08
Survey Period Figure 7-4: Mean density of scleractinian recruits m-2 (±SE) in the 1-5cm size class for shallow (1.5– 5.0m) and deep (5.1–10.0m) sites around Curieuse and Praslin (n= number of quadrates, 5 sites were surveyed in July-September 2007 and July-September 2008, 4 sites were surveyed in January-March 2008).
7.1.4.5 Family Specific Diversity Genus and family of individual recruits were recorded, and comparisons made of mean recruit density at family level. Faviidae and Poritidae populations consistently supported the highest densities of recruits (3.6m-2 ±0.31mSE and 2.77m-2 ±0.2SE respectively for July-September 2008). Acroporidae and Pocilloporidae families are also well represented in Curieuse and Praslin (1.69m-2 ±0. 18mSE and 1.47m-2 ±0.17SE respectively for July-September 2008), (Figure 7-5). Poritidae recruits have shown the greatest increase from 1.83m-2 ±0.19mSE in July-September 2007.
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July-Sept 07
-2
Recruit Density m (+/-SE)
4.5
Jan-Mar 08 July-Sept 08
4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5
F ME
Ac
rop ori da Po e c ill opo rid As ae tro co en i ida e Po ri ti da e Ag a ri ci id Sid ae era s tr ei d ae Oc u lin i da e Fa vii d ae Mu ss i da e Pe c tin iid a e Me rul i nid ae Eu ph yl li De da nd e rop hy l liid ae Fu ng ii da e
0.0
Scleractinian Family
Figure 7-5: Mean density of recruits within different scleractinian families (±SE) in the 1-5cm size class over time, at all sites surveyed around Curieuse and Praslin (5 sites were surveyed JulySeptember 07 and July-September 2008, 4 sites were surveyed in January-March 08).
7.1.5 Discussion
As there are only three survey periods around Curieuse so far, there has been little time to show any trends in coral recruitment. However, the data does not correlate with findings from surveys performed around the North West of Mahé. Granitic sites do not show a consistent higher density of scleractinian coral recruits compared to carbonate sites, as seen in the North West of Mahé. The recruitment densities between deep and shallow zones were very similar around Curieuse and Praslin, compared to North West Mahé which shows consistently higher densities in deep zones. One similarity between survey areas is the higher number of recruits coming into the 2-5cm size class compared with 1-2cm size class, as displayed in the first and latest survey period.
Another
similarity is the predominance of coral recruits falling into the Poritidae and Faviidae families. The data gathered so far does not show a reason for these findings; it may be determined by physical factors or substrate conditions. Further surveys in the area
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should be completed using this methodology. GVI will under take this for SCMRT-MPA early in 2009.
8. Community Development 8.1 National Scholarship Programme The National Scholarship Programme is directly funded by GVI Expedition Members payments and aims to increase long term capacity building in country. National recruits, such as rangers, researchers and students are selected by the local partner organisations, and are brought into either the 5 week or 10 week programme as feasible. The National Scholars are treated the same as all other Expedition Members and are expected to learn their target species and fully participate in all surveys and activities. In order for the SCMRT-MPA to continue and build upon the research conducted by GVI, scholars are invited to join every expedition from the pool of SCMRT-MPA staff. This programme has already proved highly successful with several scholars going on to return to SCMRT-MPA and gain promotions. Unfortunately there were no SCMRT-MPA research assistants available to join the expedition at Cap Ternay this phase, but it has been arranged for a scholar who learnt the coral genera and studied the recruitment methodology in 2007, to return to Cap Ternay for another five weeks to undergo GVI’s fish species training, along with two new research assistants.
8.2 International School Work Due to the school holiday lasting from July to September, GVI’s work with the International School did not take place this phase. Once the school year resumes, the weekly marine themed lessons taught on Port Launay beach by GVI Expedition Members, will start again. However, EM’s have been hard at work this phase reorganising the existing lesson plans and creating five new lesson plans to start teaching next phase; Outer Islands of the Seychelles, Coral Reefs, Introduction to the Marine Environment, Cold Environments and Invertebrates. Developments have also been made to expand teaching to another school on Praslin Island in 2009. It is still strongly believed that community education is a vital part of the expedition and an aspect that needs development to include adults in addition to the children taught.
8.3 Annual Seychelles Regatta
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GVI strives to take an active role to benefit the community and take part in local events. On 30th and 31st of August 2008, the Seychelles held their annual Regatta event in Beau Vallon to raise funds for local charities. This year GVI brought enthusiastic Expedition Members willing to face paint and work the infamous sponge throwing game board, which has been one of the highest money makers during the previous Regatta events. Over the weekend GVI raised 2,686 rupees for the Seychellois community.
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9. References Engelhardt, U (2003). SEYMEMP Interim Report No 3. Report on scientific field studies and training activities.
Reefcare International Pty Ltd, Technical Report, Townsville,
Australia, 46pp.
Engelhardt, U., 2004.
The status of scleractinian coral and reef-associated fish
communities 6 years after the 1998 mass coral bleaching event. Reefcare International Pty Ltd, Technical Report, Townsville, Australia, 129pp.
Engelhardt, U (2005). The Biodiversity Characteristics and Ecological Status of the Marine and Terrestrial Environments of D’Arros Island and St Joseph Atoll, Amirantes, Seychelles. D’Arros Research Centre Technical report No.1, 101pp
Goreau, T.T (1998). Coral recovery form bleaching in Seychelles December 1998. Unpublished report.
Global Vision International, 2007. Seychelles Expedition Report – January to March 2007. GVI (unpublished), 38pp.
Haughton, J.D.R., Callow, M.J., & Hays, G.C. (2003). Habitat utilisation by juvenile hawksbill turtles (Eretmohelys imbricata, Linnaeus, 1766) around a shallow water coral reef. Journal of Natural History 37: 1269-1280.
Spencer T., Teleki K. A., C. Bradshaw and Spalding M. D., 2000. Coral bleaching in the Southern Seychelles during the 1997 – 1998 Indian Ocean Warming event. Marine Pollution Bulletin 40(7): 569-586.
Payet, R., Bijoux, J. & Adam, P-A., 2005.
Status and Recovery of Carbonate and
Granitic Reefs in the Seychelles Inner Islands and Implications for Management, in: Souter, D. & Lindén, O. (Eds.), Coral Reef Degradation in the Indian Ocean. CORDIO, pp. 132-145.
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Wallace, CC (1985). Seasonal Peaks and Annual Fluctuations in Recruitment of Juvenile Scleractinian Corals. Marine Ecology Progress Series 21: 289-298.
Wendling, B., Engelhardt, U., Adam, P.A., Rosin, G., Alcindor, R., Zialor, V. & Louange, A. (2002). Bleaching Event in the Inner Granitic Island of Seychelles in April-June 2002, Impact of Branch Coral Recruits (Acopora spp., Pocilliopora spp., Faviidae spp.). Report for the Ministry of Environment and Natural Resources, Seychelles (MENR), pp1-9.
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10.
Acknowledgments
We kindly thank the following expedition members for their valuable contribution to this monitoring phase. Tim Kirkpatrick, Katy Seto, Genevieve Gammage,Rachel Mowll, Ben Herington, Richard Kearton, Rosie Simpson, Hazel Long, Claire Collis, Alex Feck, Alice Rietveld, Aileen McManus, Brenton Goodhart, Chris Baynes, Ciara McCarten, Emily Cray, Emma Silverton, Emma Carmen Snuggs, Julia Goggins, Julia Chapman, Katie laming, Katie Draper, Lisa Trussler, Mark Ellinor, Matthew Keetly Michael Harris, Sahil Kejriwal, Sam davenport, Sarah Flinn Campbel, Val Eaton, Wayne Lee, Alex Moon, Janice Houghton, Jenny Caston, Shelly Harper, Patrick Assouad, Shawn Morgan and Tim Howe.
11. Appendices Appendix A. Target Coral Identification List
Acroporidae
Fungiidae
Merulinidae
Acropora
Fungia
Merulina
Montipora
Cycloseris
Hydnophora
Astreopora
Diaseris
Faviidae
Pocilloporidae
Herpolitha
Montastrea
Pocillopora
Podabacia
Favia
Stylophora
Siderastreidae
Favites
Seriatopora
Siderastrea
Cyphastrea
Poritidae
Pseudosiderastrea
Plesiastrea
Porites
Psammacora
Leptastrea
Goniopora
Astrocoeniidae
Diploastrea
Alveopora
Stylocoeniella
Platygyra
Dendrophylliidae
Agariciidae
Leptoria
Turbinaria
Pavona
Oulophyllia
Euphyllidae
Leptoseris
Goniastrea
Physogyra
Gardineroseris
Echinopora
Mussidae
Coeloseris
Pectiniidae
Lobophyllia
Pachyseris
Pectinia
Symphyllia
Oculinidae
Mycedium
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Acanthastrea
Galaxea
Echinophyllia
Blastomussa
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Appendix B. Target Invertebrate Identification List
Sea Stars - (Asteroidea) Cushion Sea Star Culcita sp. Crown of Thorns Sea Star Acanthaster planci Any Additional Sea Star Species Sea Urchins (Echinoidea) Long Spine Black Sea Urchins Diadema spp. Mathae’s Sea Urchin Echinometra spp. Short Spine Black/Banded SeaUrchins Echinothrix spp. Pencil Urchin Flower Urchin Toxopneustes sp. Cake Urchin . Any additional Sea Urchin Species Bivalves (Bivalvia) Giant Clams Tridacna spp. Univalves (Gastropoda) Drupella Shells Drupella spp.
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Appendix C. Target Fisheries Identification List Sea Cucumbers (Holothuroidea) Lollyfish Holothuria artra Elephant Trunk Holothuria fuscopunctata White teatfish Holothuria fuscogilva Black teatfish Holothuria nobilis Pentard Holothuria sp.* Bohadschia spp. Actinopyga spp. Yellow Surf Fish Actinopyga mauritiana Stichopus spp. Prickly Redfish Thelenota ananas Flowerfish Pearsonothurian graeffei Royal / Amberfish Thelenota anax Octopus (Octopodidae) Octopus sp. Common Reef Octopus Lobsters (Paninuridae & Scyllidae) Spiny Lobsters Panulirus sp. Slipper Lobsters Parribacus sp./Scyllarides sp. * Taxonomy status uncertain
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