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Rare Slime Sponge Re-discovered in Scilly
22
Jun�
2009
Divers from Cornwall, Devon and the Isles of Scilly have spent a week surveying the reefs and tidal channels around the Isles of Scilly including sites that had never previously been dived. The Seasearch surveys form part of the Isles of Scilly Wildlife Trust�s Marine Biodiversity Project which aims to increase knowledge of nationally important marine habitats beneath Scilly�s seas.
Slime Sponge photo by Emily Priestley
Funded by Natural England and The Crown Estate, the Isles of Scilly Marine Biodiversity Project seeks to work with local people in Scilly as well as national marine experts to explore and scientifically record the marine life of the reefs, seagrass beds and other special habitats.
The team included expert marine biologist Dr Keith Hiscock, who first dived these waters in the late 1960s. Dr Hiscock has long recognised the importance of the Isles of Scilly for marine life, and led surveys in the 1980s that catalogued the seabed marine life at 46 intertidal and 67 subtidal locations.
Over 25 years later, guided to promising locations by local dive boat skippers and Dr Hiscock�s expert advice the team found new sites rich in sponges and fragile corals. These delicate, slow growing species only occur under certain conditions on rocky reefs and Scilly has some very good examples of thriving sponge communities. Keith said �one particular site was �solid� with fragile sponges including several colonies of a turreted slime sponge that I haven�t seen since 1969 as well as a very high abundance of nationally scarce football sea squirts and two species (a stalked sea squirt and a false cowrie) that may be new to science�.A Burrowing Anemone of the Tideswept Channels by Angie Gall
The week long expedition was led by Marine Project Officer Angie Gall from the Isles of Scilly Wildlife Trust. Each day the team conducted two dives at selected sites and then spent the rest of the day back at their make-shift laboratory identifying species from photographs, preserving specimens, pressing seaweeds for their records and making detailed notes about the dives. Angie said �the atmosphere this week has been brilliant � there has been a real spirit of discovery. Each day we were excited by what we were finding and we were learning more and more�.
All the information from the surveys feeds into local and national databases and will be used for conservation. Although it has long been known that the Isles of Scilly are important for marine life, the Marine Biodiversity Project offers an unprecedented opportunity to find out where the richest sites are and what these marine communities are made up of.
The surveys looked at sites on all sides of the islands including the Crim Rocks, which are exposed to the full force of the Atlantic. These dramatic reef walls are smothered in anemones and hydroids and during the survey hosted large numbers of red nudibranch seaslugs which are currently breeding and laying eggs.
In the tideswept channels the team recorded diverse red seaweeds and burrowing anemones in the sandy seabed. Whilst on the more sheltered rocky reefs the sponges, pink sea fans and potato crisp bryozoans flourished. Football sea squirts and yellow cluster anemones were highlights of some of the dives and the team were lucky to spot the tiny sea fan anemone growing on some of the sea fans. But nothing could beat finding the rare sponge that Dr Hiscock first saw and photographed on these reefs back in the late 1960s; the slime sponge topped off the week.
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