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OPISTHOBRANCHS OF THE TUKANG BESI ARCHIPELAGO, S.E. SULAWESI 1999 SURVEY REPORT & RESULTS |
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by Lindsay Warren |
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Background Work on cataloguing marine species groups to be found in the seas of the Tukang Besi Archipelago was started in a modest way in the last two weeks of the survey season in 1997. At the end of that time a total of 60 different species of opisthobranch had been found of which several are new to science. During the 10 months of the 1998 season, all efforts of volunteers were concentrated on building lists of species in three main groups porifera, ascidians and opisthobranchs. The opisthobranch list was expanded to 175 of which 20 have yet to be fully identified to species level. Participants The 1999 survey season ran from early May until the third week of October. During this time over 40 volunteers from England, Scotland, Ireland, Switzerland, Japan, Sweden, Spain, Turkey, and Wales contributed to the opisthobranch survey programme. Training On arrival at the Marine Survey Base on Pulau Hoga, volunteers were given a 5 day training programme to enable them to carry out effective surveys. The programme comprised:
Methodology Dive Schedule For the majority of the season survey dives were carried out in the late morning and afternoon. Dives would be to a maximum of 20 metres with pairs of divers covering different sections of the chosen reef. The area covered by each pair was typically a narrow band gradually going from the deepest point to shallower areas. In some cases larger areas were covered during the course of a dive due to strong currents. For the last month of the survey period, survey dives were carried out in the early morning which allowed dives to a maximum of 30 m and at night which revealed species that only emerge at night from holes in the reef. Surveys were also carried out during the day and at night in intertidal areas both at high and low tide. |
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Locations Sites around Pulau Hoga and the north eastern end of Pulau Kaledupa were surveyed extensively. In addition to this we were able to survey sites on the islands of Tomia, Tolandono, Kampenaune, Kapota, Wangi-Wangi, Lintea and on the karangs of Tokobao and Kaledupa.
Data Collected For all specimens found, volunteers were required to collect the following information: Date and time of day Size of specimen Overall topography of location Depth at which found Surface on which found Whether it was feeding and if so on what Type of movement Presence of egg mass Other observations of interest This information will form the basis of a database which will enable one to gain an insight as to the relative abundance of each species along with where and when they are commonly found. Research worldwide into opisthobranchs and their biology is relatively new but has been growing at a much greater pace over the past 20-30 years. The data will potentially indicate which habitat zones are of particular importance to the survival of different groups or species of opisthobranchs.
Identification of Specimens Where possible, opisthobranch specimens were identified on site and left in situ. However, as many are difficult to positively identify without the help of published literature, volunteers were able to collect them in protective containers. These were then taken either to the marine survey base or to the live-aboard dive boat and held temporarily in containers or an aquarium while the literature and specimens were compared. |
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Illustrations and Photography The majority of specimens collected and found for the first time whether identified or not were photographed to build up a photographic record. In the case of ones which could not be positively identified, detailed illustrations were made along with notes regarding special features. The quality of illustrations this year was consistently high which is very helpful when trying to identify specimens. Examples of illustrations follow.
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Selection of Photographs of Opisthobranchs Found During 1999 all photos by Lindsay WarrenÓ |
The Tukang Besi Archipelago, S.E. Sulawesi
