Journal of the Marine Biological Association of India

Distribution, diversity, length-weight relationship and recruitment pattern of deep-sea finfishes and shellfishes in the shelf-break area off southwest Indian EEZ

Volume 48 Issue 1

A.A.Jayaprakash, B.Madhusoodana Kurup, U.Sreedhar, S.Venu, Divya Thankappan, Hashim Manjebrayakath, Anish V.Pachu, Paul Thampy and Siva Sudhakar

Abstract

The results of an exclusive fishing cruise, No. 241, undertaken by FORV Sagar Sampada (Ministry of Earth Sciences) during January-February 2006, in the shelf-break area (500-1000 m depth) in the southwest region of Indian EEZ (Lat. 9⁰-16⁰ and Long. 72^0- 75⁰46) are presented. Bottom trawling was conducted at 33 stations. A total catch of 1795 kg was realised, out of which the discards formed 311 kg. A variety of non-conventional finfishes (77 species) and shellfishes (shrimps 8 species, crabs 3 species, one species of lobsterette) have been recorded. Depth-wise 235m zone indicated the maximum catch. The total catch during the entire cruise was dominated by Psenopsis cyanea. The various population parameters such as L_α, K, total mortality (Z), natural mortality (M), fishing mortality (F), exploitation ratio (E), recruitment pattern and length-weight relationship of some of the important species have been worked out. In most of the deep-sea fishes, the recruitment appeared to take place almost throughout the year and showed great similarity among the various species except Luciobrotula bartschi. Presently, all these resources remain unexploited, except the shrimps. The trawlers based at Cochin, Quilon and Munambam have been exploiting the deep-sea shrimp resources like the red-ring Arbreus alcocki from the Quilon Bank and other similar areas of west coast for the last five years. Interestingly Psenopsis cyanea has been found to occur as bye-catch in these fishing operations. Therefore, these two species showed higher fishing mortality compared to practically nil value in other finfishes and shellfishes. The occurrence of the deep-sea glass sponge, Hyalonema sp. off Mangalore is also reported. Bio-silica, extracted from this sponge, has a vide range of applications in the medical field from novel biomaterials for bone replacements to the stabilization of tissue. Most of the resources being nonconventional there is need to evolve new processing methods, product diversification and develop export avenues to make deep-sea fishing venture a success. Inventorisation of the deep-sea biodiversity and preparation of fishery atlas also merit serious consideration.

Keywords

Deep-sea finfishes, shellfishes 500-1000 depth zone, southwest Indian EEZ

Date : 30-06-2006