Population characteristics and taxonomy of lantern fishes of genus Diaphus (Family Myctophidae) off south west coast of India

Globally most of the conventional fish stocks have reached a state of optimum exploitation or even over-exploitation; efficient utilization of non-conventional resources is necessary to meet the supply-demand gap for protein supply. Mesopelagic fishes can be considered as one such promising resource for the future, if appropriate harvest and post-harvest technologies are developed. Increasing human population and increasing demand for cheaper food fishes has made myctophids a possible potential resource for future exploitation and utilization. Earlier studies indicated the abundance of Diaphus spp. in the eastern and northeastern Arabian Sea. The present study also indicates the dominance of Diaphus spp. in the deep sea trawling grounds of south west coast of India

Lanternfishes (Myctophids): by-catch of deepsea shrimp trawlers operated off Kollam, south-west coast of India

By-catch and discards have received a great deal of scientific attention, their minimisation being a goal of marine fisheries management (Powers, 2006). The Nordic workshop (Nordic Council of Ministers, 2003) defined by-catch as “the proportion of the catch which is taken on the board, or brought to the surface by the vessel and which is subsequently thrown back to sea, dead or dying or likely to die”. Most of the earlier studies deal with optimisation of fishing efficiency and minimisation of fishing impact, but by-catch and discards data have rarely been used to learn about the distribution, abundance and biology of the incidental species being caught, although several recent studies have indicated the informative value of by-catch concerning food habits (Koen Alonso et al., 2001), feeding ecology (Rheeder and Sauer, 1998) and recruitment indices (Payne et al., 2005)

Myctophid fishery along the Kerala coast with emphasis on population characteristics and biology of the headlight fish, Diaphus watasei Jordan & Starks, 1904

Myctophids form bycatch in deep sea shrimp trawls with an annual average catch of 2668 t during 2009 - 2011 in Kerala coast. Fishery occurred almost round the year with peak during November - February. Fishery and biology of the dominant species, Diaphus watasei was monitored. Peak spawning and recruitment of the species was during January-August. Growth parameters L∞ and K are estimated as 15.06 cm and 0.8 per year respectively. These values indicate that the species growth is relatively fast. Natural mortality estimate (M) is 1.21, total mortality (Z) 1.68 and fishing mortality (F) 0.47. The exploitation rate (E) is low being 0.279. These indicate that the stock is at its initial stage of exploitation and there is large scope for enhancing their commercial exploitation. The stock abundance, biomass and distribution of the resource need to be assessed. These factors have to be taken into consideration while planning for exploitation of myctophids in future

First record of the Garman's lanternfish Diaphus garmani (Family: Myctophidae) from Indian waters

The myctophid Diaphus garmani is recorded for the first time from Indian waters. Three specimens (54-59 mm standard length) were collected from deep sea shrimp trawlers off Quilon, southwest coast of India, between 80 -110 N and 740-760 E, at depths from 250 to 450 m

Preliminary study on the length-weight relationship of Sacura boulengeri (Heemstra, 1973) from Indian waters

Sacura boulengeri (Heemstra, 1973) is a rare serranid fish (Subfamily: Anthiinae) having very distinct distribution in the western Indian Ocean. The rarity of the species is evident from earlier reports and, so far, no related studies on the species have been published except on taxonomy and distributional records. In the present investigation, the length-weight relationship of Sacura boulengeri was estimated to be W = 0.0777 × L2.690 (with 95% confidence intervals for b and r2). An analysis of the stomach contents revealed that sergestid shrimps and copepods were the major food items of the diet

Proximate composition and fatty acid profile of the myctophid Diaphus watasei Jordan & Starks, 1904 from the Arabian Sea

The edible portion of Diaphus watasei, a benthopelagic fish collected off Quilon, south-west coast of India was analysed for proximate composition and fatty acid profile. The fleshy part of the fish was found to contain 15.62% protein, 11.71% fat, 0.47% minerals, 0.28% soluble carbohydrate and 0.01% crude fibre. The dry matter in the fish was found to be about 28%. Monounsaturated fatty acids (MUFA) were found to have the highest (36.7%) share among total fatty acids followed by saturated fatty acids (SFA) (33.3%) and polyunsaturated fatty acids (PUFA) (25.5%). The abundant fatty acids were found to be oleic acid, palmitic acid, docosahexaenoic acid, stearic acid, myristic acid, linolenic acid, eicosapentaenoic acid and palmitoleic acid. The most predominant fatty acid was recorded as oleic acid which contributed 32% to the total fatty acids. Docosahexaenoic acid formed the single largest component of PUFA (9.33%) followed by γ linolenic acid (3.97%) and eicosapentaenoic acid (3.83%). The ω-3 PUFA contributed about 70% of the total PUFAs. The most important ω-3 PUFAs were EPA and DHA that contributed 73% to the total ù -3 polyunsaturated fatty acids

Morphometric characteristics of deepwater stingray Plesiobatis daviesi (Wallace, 1967) collected from the Andaman Sea

The present paper reports on the morphometric characteristics of two specimens of Plesiobatis daviesi collected during the deep-sea fishery resource survey of FORV Sagar Sampada in the northeastern Andaman Sea off Diglipur (130 14’ N lat; 930 09’ E long.) at 320 m depth and off Mayabandar (120 48’ N lat; 930 07’ E long.) at 369 m depth

Fishery, biology and dynamics of dogtooth tuna, Gymnosarda unicolor (Rüppell, 1838) exploited from Indian seas

Dogtooth tuna, Gymnosarda unicolor (Rüppell, 1838) (Fig. 1) is a pelagic tuna preferring waters of temperature between 21 and 26 oC. It is one of the principal species exploited by hook and line (recreational as well as commercial fishery) operated in the oceanic region. Meat of dogtooth tuna is white and so it has great demand and fetch high price (IUCN, 2011). However, occasional ciguatera fish poisoning in humans has been reported on consumption of dogtooth tuna. It is exported in fresh and frozen state and is used for the production of sashimi, canned tuna, and pouch products. Most of the world landings of dogtooth tuna during 1963 -2006 was from the Indian Ocean. Small scale tuna long lines for the species operating in the Indian Ocean belong to Taiwan, Srilanka, Maldives, Japan or Pakista

Fishery, population dynamics and stock structure of frigate tuna Auxis thazard (Lacepede, 1800) exploited from Indian waters

Auxis thazard, commonly known as frigate tuna represents an important group of coastal tuna species occurring in the Indian waters. The species is landed all along the Indian coastline and the major landing is along the south-west coast with Kerala contributing the most. The species is exploited by a variety of gears viz., drift gill nets, shore seines, ring seines and hooks and lines. Though there is recent information on the fishery and the exploitation status of Auxis thazard from Tuticorin (Kasim, 2002; Abdussamad et al., 2005) and Veraval (Ghosh et al., 2010), studies on the catch, population characteristics and stock estimates covering the entire coasts of India are lacking after the work of Silas et al. (1985) and James et al. (1993). These studies date back to two decades, after which there has been a change in the fishing pattern of coastal tunas throughout the country. Therefore, the present study was undertaken to provide an insight into the fishery, population dynamics and stock structure of A. thazard exploited from Indian water

Taxonomy and key for the identification of tuna species exploited from the Indian EEZ

Tuna samples were collected from the commercial landings at Kochi, Tuticorin, Mangalore, Visakhapatnam, Veraval and Lakshadweep at regular intervals during 2006-2010. Detailed morphometric data, viz., height of dorsal and anal fins, eye diameter, snout length, head height and height of body were collected. Otoliths were collected from eight species and analysed. Results indicated that structure and shape of the otoliths show species specific differences. Taxonomic details of tunas and tuna like species have been generated from the present as well as past studies and the species were redescribed with color photographs and keys for identification. The species included Thunnus albacares (Bonnaterre, 1788), Thunnus obesus (Lowe, 1839), Thunnus tonggol (Bleeker, 1851), Sarda orientalis (Temminck & Schlegel, 1844), Katsuwonus pelamis (Linnaeus, 1758), Euthynnus affinis (Cantor, 1849), Auxis thazard (Lacepède, 1800), Auxis rochei (Risso, 1810) and Gymnosarda unicolor (Rüppell 1836)