Deep-sea teleostean species-diversity off the south west coast of India (7° N-10° N lat.)

During the exploratory fishery survey conducted by M.F.V. Matsya Varshini of the FSI, Kochi base from February 2004 to April 2005 for assessing the abundance and distribution of the nonconventional deep-sea fin fish resources, an attempt has been made to prepare an inventory of the teleostean species-diversity in the 100 to 500 m depth zone off the south-west coast of India. A checklist of the 98 species belonging to 16 orders, 52 families, and 79 genera collected during the period along with the area and depth of collection is presented. The classification is based on Nelson (1984). Of the 98 species, 17 are identified to the generic level only. Even though this is not an exhaustive study, the presence of 16 orders and 98 species in the 100 to 500 m depth zone is a clear indicator of the rich teleostean species-diversity of this region. Global deep-sea demersal fish fauna is represented by 22 fish orders. Out of the 98 species recorded, 63 belong to the pre-perciform orders.The order Perciformes dominated the diversity with 29 species, followed by the order Lophiiformes (ten species) and order Scorpaeniformes (nine species). Families Myctophidae and Macrouridae with five species each topped in species diversity. Out of the 52 families, 22 families were represented by a single species. Families Cepolidae, Uranoscopidae, and Ariommatidae were represented in the 100-200 m depth zone only. A comparative account of the number of species recorded during previous surveys is furnished. Diversity indices using catch data collected through surveys of the south west coast of India have been worked out and explained in order to relate it with abundance indices. In future fishery surveys, emphasis must be given to exhaustive species-diversity studies and to make available specimens to facilitate the bar coding of the species.