Distribution of gorgonids in the northeast coast of India with particular reference to Heterogorgia flabellum (Pallas)

Abstract

During the 5lst Cruise of FORV 'Sagar Sampada' extensive trawling at 6 stations between Lat. 16O00' and 20°00' N and in depths varying from 37 to 68 metres indicated the presence of gorgonids in 3 stations viz. NO.' 7, 11 and 23. The total quantity collected from the above stations was approximately 500 kg. Analyses of samples collected indicate the presence of 12 species of gorgonids in this area and are referable to 9 genera under 4 families. The dominant species was Heterogorgia flabellurn (Pallas) followed by Ellisella maculata (Studer) and E. andamanensis (Simpson). All these 3 species are now being exploited from the inshore areas also for export; the first one is commercially classified as 'black-type' while the others, under 'monkey-tail type'. Heterogorgia flabellurn is widely distributed in all the above 3 stations, but its concentration was considerably high in station 23. The maximum number of species (8) was recorded at this station. An interesting point emerged from the study is that the specimens of H. flabellurn were heavily infested with a variety of fouling organisms. Though barnacle was found to be the dominant group numerically, others such as sponges, bryozoans, corals (mainly solitary formsj), ascidians and molluscs (mainly Pteria sp.) were also present in good numbers. The presence of foulers on specimens of H. flabellurn indicated that this species synthesises no antifouling substance which will repel1 the settlement of foulers. It may also be stressed here that the detailed information on the distribution of the above species provided here is not to be used for their indiscriminate exploitation and export, but to be used for exploiting (hem judiciously) for experimental purposes. Wherever necessary, some species have also been redescribed with suitable illustrations.