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Varghese S.P.,Cochin Base of Fishery Survey of India | Somvanshi V.S.,A 1 Tower | Gulati D.K.,Fishery Survey of India
Indian Journal of Marine Sciences | Year: 2013

Present study consists the studies on the stomach contents of Indo-Pacific sailfish, Istiophorus platypterus (Shaw, 1792), caught during tuna longline survey conducted in the western Indian EEZ (eastern Arabian Sea) between 2006 and 2009 to investigate the sexual, ontogenetic and seasonal effects in the diet. Stomachs of 290 specimens in the forklength range of 101-261 cm were examined, of which 38 (13.10%) were empty. Prey composition was assessed in terms of occurrence by number, frequency of occurrence, weight and Index of Relative Importance. Quantile regression techniques were used to determine the mean and upper and lower bounds of the relation between prey size and sailfish length. Diet was dominated by teleost fishes, followed by cephalopods while crustaceans were represented in limited instances. Purpleback flying squid, Sthenoteuthis oualaniensis, was the most preferred prey species. Other important prey species identified were Euthynnus affinis, Cubiceps pauciradiatus, Gempylus serpens and Onychoteuthis banksii. Diet did not varied by sex, but the ontogenetic and seasonal variations in diet were significant. The maximum and mean size of prey increased with length of sailfish. However, relatively smaller prey constituted bulk of sailfish diet and even large specimens consumed small prey. Source

Varghese S.P.,Cochin Base of Fishery Survey of India | Vijayakumaran K.,Fishery Survey of India | Anrose A.,Chennai Base of Fishery Survey of India | Mhatre V.D.,Fishery Survey of India
Turkish Journal of Fisheries and Aquatic Sciences | Year: 2013

Distribution, abundance and biology of swordfish, Xiphias gladius, of the Indian seas were investigated by analyzing the data gathered during tuna longline surveys conducted by the Fishery Survey of India (FSI). Study undertaken during the period from 2004 to 2010 revealed swordfish Catch Per Unit Effort of 0.02 numbers in 100 hooks from the Arabian Sea; 0.01 from Bay of Bengal and 0.02 form the Andaman and Nicobar waters. About 16% of the specimens caught were juveniles and the sex ratio of smaller fishes was in favour of males, whereas, larger specimens were mostly females. Length-weight relationship established indicated slightly positive allometric growth of the species and length based models revealed difference in growth between sexes. The growth parameters estimated for females were: asymptotic length (L∞) = 311.11 cm, growth coefficient (K) = 0.17/yr and age at zero length (t0) = -0.53 yr, whereas, the growth parameters estimated for males were: L∞ = 243.79 cm, K = 0.22/yr and t0 = -0.37 yr. Diet was dominated by finfishes and cephalopods, while crustaceans were recorded rarely. Sthenoteuthis oualaniensis was the dominant prey species, followed by Paralepis sp. Spawning area was identified in the Lakshadweep waters from where mature females with hydrated oocytes were caught during December to April. Size at 50% maturity for females was estimated at 164.03 cm, which is reached at about four years of age. Mean batch fecundity was 4.5 million, while the relative fecundity was 37.5 hydrated oocytes per gram of body weight and the diameters of mature oocytes were in the range of 0.9-1.6 mm. Our results provide preliminary information on the abundance, growth and biology of this species in the Indian seas which should be useful to fishery managers. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey. Source

Varghese S.P.,Cochin Base of Fishery Survey of India | Somvanshi V.S.,Fishery Survey of India | Dalvi R.S.,Fishery Survey of India | Dalvi R.S.,Maharshi Dayanand College
Hydrobiologia | Year: 2014

Information on the ecology and feeding behaviour of the large oceanic predatory fishes is crucial for the ecosystem approaches to fisheries management models. Co-existing large pelagic predators in the open oceans may avoid competition for the limited forage by resource partitioning on spatial, temporal or trophic levels. To test this, we studied the prey species composition, diet overlap, trophic level, and trophic organisation of 12 large predatory fishes co-existing in the eastern Arabian Sea. Stomach contents of 1,518 specimens caught by exploratory longline operations in the Indian Exclusive Economic Zone during the years 2006-2009 were analysed. Finfishes were dominant prey of all species except blue marlin (Makaira nigricans) and yellowfin tuna (Thunnus albacares), which fed mainly on cephalopods, and long-snouted lancetfish (Alepisaurus ferox) and pelagic stingray (Pteroplatytrygon violacea), which fed mainly on crustaceans. Common dolphinfish (Coryphaena hippurus) and yellowfin tuna fed on a wider variety of prey than the other species, while the diets of lancetfish and black marlin (Istiompax indica) were narrowest. Pelagic stingray and great barracuda (Sphyraena barracuda) fed on species occupying epipelagic waters, whereas the contribution of mesopelagic prey was higher in the diets of swordfish (Xiphias gladius) and pelagic thresher (Alopias pelagicus). Trophic levels of these fishes ranged from 4.13 to 4.37. Diet overlap index revealed that some of the large pelagic predatory fishes share common prey species. Cluster analysis of the diets revealed four distinct trophic guilds namely 'flyingfish feeders' (common dolphinfish and great barracuda); 'mesopelagic predators' (pelagic thresher and swordfish); 'crab feeders' (lancetfish, pelagic stingray and silky shark) and 'squid feeders' (yellowfin tuna, Indo-Pacific sailfish (Istiophorus platypterus), skipjack tuna (Katsuwonus pelamis), black marlin and blue marlin). Large predatory fishes of the eastern Arabian Sea target different prey types, and limit their vertical extent and time of feeding to avoid competing for prey. © 2014 Springer International Publishing Switzerland. Source

Sajeevan M.K.,Fishery Survey of India | Somvanshi V.S.,Fishery Survey of India
Indian Journal of Marine Sciences | Year: 2013

Marine ornamental fishes form a significant share of trawl fishery, which are generally discarded. Methodology followed for live collection of marine ornamental fish and equipments used are presented in the paper. Occurrence of live ornamental fishes in the trawl catches and factors affecting the survival rate of collected fishes are discussed. A check list of 66 species belonging to 35 families collected during the study is added in the text. Altogether 22 species were recommended as most suitable species for beginners, as they are hardy and easy to maintain in the tanks. Need for an in depth study on the distribution and abundance of the marine ornamental fishes often caught in the trawl fishery of the country is highlighted to evolve exploitation and utilization strategy. Results of present study will helps to overcome the present hurdles in the industry i.e. non-availability of continues supply of ornamental fishes for stocking. Source

Sajeevan M.K.,Fishery Survey of India | Sanadi R.B.,Fishery Survey of India
Indian Journal of Fisheries | Year: 2012

Andaman and Nicobar Archipelago is bestowed with rich oceanic resources. Information on its dynamics is essential to evolve an exploitation strategy and therefore an attempt has been made to understand the diversity, distribution and abundance of oceanic resources around Andaman and Nicobar Islands by utilising exploratory tuna long-line survey data. A total of 29 species of fishes including 15 species of pelagic sharks were recorded during the study. Dominance of pelagic sharks over the target species, i.e., tuna was a major characteristic of the fishery. Drastic reduction in the composition of tuna and sharks towards total catch in recent years was noticed. Hooking rates recorded during different months and at different latitudes are presented. Sharks were dominant between lat. 080 N and 120 N, while no significant pattern was observed in the case of yellowfin tuna. Diminishing trend of hooking rates of tuna and sharks since nineties and replacement of a major share of these resources by uneconomical fishes indicates need for stringent management measures for the conservation of oceanic resources. Source

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