Neptunea nr.7

Neptunea 2(3):

Deep-water species of Mollusca in the Mozambique Channel, Part I, pp.1-27 + figs. by Frank Nolf & Johan Verstraeten.

Up to 1973, the shrimp fishery along the Malagasy coasts was still carried out at a depth of 5 to 25 metres. However, the supplies gradually started dwindling. The production could not exceed 8,000 tons per year at that time and therefore the prospecting of possible new fishing grounds along the flanks of the continental shelf at a depth of 100 to 1,000 metres was started. Especially near Toliara (SW Madagascar), the conditions turned out to be rather favourable to convert to deep sea fishing, but Mahajanga and Nosy-Bé yielded satisfactory results as well. During the exploration for the upcoming shrimp fishery more than 250 different species of crustaceans were found, a limited number of them being of real commercial value. At the end of the past century and the beginning of 21st century – a period of about ten years - shrimper boats were operating in the Strait of Mozambique at depths of 600 to 800 m, between Toliara and Morondava. Among the attractively coloured shrimps of an average size between 20 and 33 centimetres – especially in demand by Japanese consumers – dozens of molluscan species were found, many of them new to science. Unfortunately, most shells were caught with hermit crabs inside and thus often in bad condition due to the presence of their hosts or the use of trawler-nets.
In a trilogy a systematic overview is presented with the most important finds of the past decade. Part I deals with the Gastropoda (Pleurotomariidae, Lottiidae, Trochidae, Turbinidae, Xenophoridae, Cypraeidae and Naticidae). The species of seashells are comprehensively described and illustrated. Efforts are undertaken to compare with representatives in other seas.

Key words: Mozambique Channel, Madagascar, Toliara, Mahajanga, deep-water molluscs, Gastropoda.