AMP 2008 expedition

  • In December 2008 the Aldabra Marine Programme (AMP) team of Drs Ben Stobart, Ray Buckley and Nigel Downing were joined by Rodney Quatre, Research Manager of the Seychelles SCMRT –MPA, to undertake a complete survey of all Aldabra Marine Programme sites in the southern Seychelles.  Aboard the Indian Ocean Explorer the team was joined by owners Peter and Maureen Holland.


 

  The AMP team from left to right: Ray Buckley, Ben Stobart, Nigel Downing and Rodney            Quatre.

 

  • After initial consultations in Mahé with interested parties (Seychelles Islands Foundation, Ministry of the Environment, Island Conservation Society) surveys started in Aldabra on the 13th December and concluded there on the 22nd of December.

 

  • While at Aldabra the AMP team was joined by Ranger Ritval Pillay, and volunteers Rebecca Scott and Bernard Coetze from the Aldabra station. All the Aldabra site surveys (9 in all) followed previous AMP protocols.

 

  • We removed data loggers from all sites for downloading.  New instruments were installed at selected sites.

 

  • Weather conditions were generally good although underwater visibility at the beginning of the surveys was poor.

 

  • Caulerpa, which covered the 20m transect line at Site 5 in 2006 had all but disappeared. However, stolons remained and we will continue to monitor changes in this habitat phase shift.


 

  Caulerpa sp. overgrowing and competing with Sarcophyton sp. soft coral.

 

  • Fish populations at all external reef sites were healthy.

 

  • The soft coral Rhytisma remains prominent though initial impressions suggest that there have not been further increases.

 

  • There was little evidence of coral disease, which was prominent in December 2006. In the lagoon, the Passe Houareau fish population maintains its rich diversity.

 

  Large potato cod (Epinephelus tukula) patrolling the reef at Aldabra.

 

  • We left Aldabra on the 22nd December and resumed surveys at Assomption on the following day.  Unusually, we had very low visibility in the upper layer at the survey site, where normally we have clear water.  The caesionid, Pterocaesio tile, remains the dominant fish in numbers at the site, and the large grouper population appears to be intact.

 

  • However, on the other side of the island we detected a new extensive outbreak of the alga Caulerpa.  At 26m and below it covers some 80% of the substrate. Within this outbreak there were white dead patches of Caulerpa resulting from unknown causes.

 

  • The structure of the fish population on this side of the island is notably different although this is likely due to the exposure of this area rather than due to the Caulerpa  coverage.


  • Christmas Eve saw the team at Astove. Diving conditions were poor with sub-optimal visibility.  At Site 2 we detected a significant reduction in the numbers of big fish, particularly the serranids and lutjanids.

 

  • This tied in with various reports that heavy fishing is now taking place at Astove, both commercially and recreationally.

 

  • We were able to locate and survey our Site 1 on the NE side of the island which was last visited in the summer of 2002, but not since due to adverse weather conditions.

 

  • This site was heavily covered with Caulerpa in 2002, and is now almost completely clear of the alga.  As at Site 5 Aldabra, stolons are still present though not common.

 

  • We celebrated Christmas Day at sea in transit to our final destination, St Pierre, at which we arrived early afternoon.

 

  • This uninhabited island was struck by a cyclone on the 26th December 2006. The devastation was apparent from the state of the Casuarina and coconut trees on the NW side.  Furthermore, a beach has also been formed on the affected side of the island, near the old rock phosphate mine settlement.

 

  • The devastation was also apparent underwater at our monitoring site.  At 10m there is a covering of about 2m of sand over the entire 50m transect line, but in spite of this we were able to dig to the top of the 10m stake and retrieve our temperature data logger.

"Rodney recording a video transect at Aldabra"


 

  • The 20m line was mostly intact.  At 20m most corals are dead and surrounded by sand.  There is a continuous movement of sand down-slope.

 

  • The expedition concluded on the 29th December when the Indian Ocean Explorer reached Mahé. That day the team reported its findings to Dr. Frauke Fischer-Dogley, Lindsay Chong-Seng and informally to a gathering of part of the SIF Board. Finally a meeting was also held with Rony Renaud, MD of SCMRT -MPA.


 

AMP 2006 expedition

In November-December 2006 the AMP team returned to Aldabra and Assomption to conduct surveys of all sites and download temperature data loggers.  This time in the team were Dr. Nigel Downing, Dr. Ray Buckley, Mr. Alan Smith and Dr. Ben Stobart.  The team was pleased to have Alan Smith along as he is an extremely experienced diver and field biologist, and was a great asset to the expedition (see team photo below).  This time our work base was the support vessel Hydra and its crew that came up from Madagascar.

 

  The AMP team from left to right: Ray Buckley, Ben Stobart, Alan Smith and Nigel Downing

 

This year the team was lucky to be sponsored by the Seychelles Islands Foundation that provided a return flight to the remote island of Assomption, 30 miles from Aldabra.  A total of twelve sites were surveyed during the two week stay at Aldabra and Assomption, and almost 40 temperature data loggers downloaded from select sites.

 

Ray Buckley and Nigel Downing conducting fish surveys at Assomption

 

Initial results suggest that the coral reefs at Aldabra have changed very little since our last visit, though it seems that coral growth had improved this year.  We will not be sure of this until video transects have been analysed.  Full results will be included in our 2006 report later this year.


 

 


 

Alan Smith repairing broken permanent transect line (left) and transect marker buoy (right) encrusted with Halimeda calcareous alga (bottom and top), Dendronepthya soft coral (right) and also note small Pocillopora coral recruit in the center of the encrusted buoy (brown colour). 


The AMP particularly wishes to thank the Seychelles Islands Foundation for their ongoing support which made this expedition possible. 


 

AMP activities in 2005

In April 2005 the AMP team conducted a full expedition to survey all permanent monitoring sites at Aldabra, Assomption, Astove and St. Pierre on board the catamaran Lady Anja.  The team consisted of Dr. Ray Buckley, Dr. Nigel Downing, Dr. Ben Stobart and Miss Elise Granek.  We were also joined by Dr. Bernhard Wessling from Germany who assisted tirelessly with all research tasks.  Dr. Wessling is an expert on cranes amongst other things, and has his own website dedicated to the preservation of these beautiful birds (http://www.craneworld.de/)

 

                                The Team getting ready to fly down to Desroches


 

                                The Lady Anja, a fine research support vessel!


 

                                The AMP dive team (Ben Stobart, left; Ray Buckley,                                 
                                middle; Nigel Downing, right)