project news

Nudibranchs Laid Bare

News item submitted by Frontier
News item dated 29 Apr 2010


Nudibranchs meaning ‘naked gills’ are marine molluscs, which are generally small and brightly coloured. They have developed these characteristics to warn off predators or camouflage into their surrounding environment. Due to their fascinatingly colourful patterns, they have long been a favourite of the recreational scuba diver. Though interestingly, there are very few professional biologists worldwide specialising in the study of these animals and knowledge of nudibranchs is generally limited, especially in Madagascar. Frontier Marine Camp have recorded these colourful critters to order level as part of the baseline surveys being conducted in the Bay of Antsiranana since 2005. This study is designed to try and find out more about their distributions and habitat preferences. 

After 56 long hours of searching over a fifteen-month period, 31 nudibranch species have been found. Last month, the species Chromodoris aspersa was recorded for the first time within the bay, and all signs seem to indicate that there are many more to be found. Across Madagascar, from Ile Sainte Marie, Toliara, Tolaganaro to Nosy Be, a total of 175 species of nudibranchs have been collected in recent years, including a number of species new to science!

Some locations within the Bay appear to be preferred by nudibranchs, supporting higher numbers of individuals and species. This may be due to the different populations of prey species in different locations, as they are carnivores and usually prey on sessile animals like sponges, corals or anemones. Protection from predators is another important factor for habitat protection as they have a soft body with no shell to protect them. The Madagascar team are looking forward to conducting further surveys that should help clarify their geographical and seasonal variations.

Hannah Burton

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