Cochin Base of Fishery Survey of India

Cochin, India

Cochin Base of Fishery Survey of India

Cochin, India
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Varghese S.P.,Cochin Base of Fishery Survey of India | Gulati D.K.,Cochin Base of Fishery Survey of India | Unnikrishnan N.,Cochin Base of Fishery Survey of India | Ayoob A.E.,Cochin Base of Fishery Survey of India
Journal of the Marine Biological Association of the United Kingdom | Year: 2015

Reproduction, diet and growth of silky shark Carcharhinus falciformis in the eastern Arabian Sea are described based on 473 specimens collected from the gillnet-cum-longline landings at the Cochin fisheries harbour during 2012–2014. The reproductive biology of 215 males and 258 females was examined while 113 stomachs were sampled to study the diet. The von Bertalanffy growth parameters estimated using length-based models were asymptotic length (L ∞) = 309.80 cm, growth coefficient (K) = 0.10 year−1 and age at zero length (t 0) = −2.398 year. The sex ratio was significantly skewed to females. Seasonality in reproduction was not evident and in males, sexual maturity was attained at 201–223 cm total length (L T) with the size at maturity (L T50) occurring at 217.0 cm, whereas in females sexual maturity was attained at 224–231 cm L T and L T50 occurs at 226.5 cm. In total 114 embryos, in the length range of 12.2–65.1 cm were recovered from 15 pregnant females. Numbers of embryos in females were in the range of 3–13, averaging 7.6. Silky sharks of the eastern Arabian Sea feed primarily on swimming crab Charybdis smithii, with juveniles feeding principally on swimming crabs, while adults feed on actively swimming prey like squids and teleost fishes. This preliminary information on the reproduction, diet and growth should be useful to identify management strategies for silky sharks in the eastern Arabian Sea. Copyright © Marine Biological Association of the United Kingdom 2015


Varghese S.P.,Cochin Base of Fishery Survey of India | Unnikrishnan N.,Cochin Base of Fishery Survey of India | Gulati D.K.,Cochin Base of Fishery Survey of India | Ayoob A.E.,Cochin Base of Fishery Survey of India
Journal of the Marine Biological Association of the United Kingdom | Year: 2016

Studies on reproduction in sharks are important for their management, since the attainment of sexual maturity has a substantial impact on their distribution, behaviour and biology. However, reproductive biology of large oceanic sharks is poorly studied in the Indian seas. In this study, the size structure, sex and maturity of pelagic thresher (Alopias pelagicus), bigeye thresher (A. superciliosus), oceanic whitetip shark (Carcharhinus longimanus), tiger shark (Galeocerdo cuvier), shortfin mako (Isurus oxyrinchus), longfin mako (I. paucus) and blue shark (Prionace glauca) in the eastern Arabian Sea are described based on 1449 specimens collected from gillnet-cum-longline landings at the Cochin fisheries harbour during 2013–2014. Sex ratios of sampled specimens were biased to males in pelagic thresher, bigeye thresher, tiger shark and blue shark, while females dominated in the specimens of oceanic whitetip shark. Females matured at greater lengths than males in all species except oceanic whitetip shark. Lengths at maturity for males were in the range of 189.05–286.56 cm, whereas those of females were in the range of 187.74–310.69 cm. Litter sizes of both the thresher shark species were always two, while in oceanic whitetip shark, litter size was 3–9 and 22–51 in tiger shark. Seasonal reproduction was noticed in oceanic whitetip shark and tiger shark. Pregnant females were not found in the blue shark, shortfin and longfin makos sampled during the study period. Reproductive aspects of pelagic thresher, bigeye thresher, oceanic whitetip shark, tiger shark, shortfin mako, longfin mako and blue sharks in the eastern Arabian Sea are generally consistent with earlier reports from other regions of the world's oceans. These preliminary findings should be useful to identify suitable management measures for the above shark species. Copyright © Marine Biological Association of the United Kingdom 2016


Varghese S.P.,Cochin Base of Fishery Survey of India | Vijayakumaran K.,Fishery Survey of India | Tiburtius A.,Fishery Survey of India | Mhatre V.D.,Fishery Survey of India | Mhatre V.D.,West Marine
Indian Journal of Geo-Marine Sciences | Year: 2015

Diversity and abundance of pelagic shark bycatch in the tuna longline operations in northern Indian Ocean were examined for the period 2004-2010. During the survey 1.2 million hooks were deployed in three regions of seas around India resulting in the catch of 1501 numbers of sharks. Significant variations in the diversity and abundance of pelagic sharks were observed among the three regions of Indian seas. Catches of sharks are prominent in Andaman & Nicobar region contributing 35.15% of the catch by number and 51.46% by weight. In the eastern Arabian Sea, sharks constituted 15.49% and 14.89% of the total catch by number and weight respectively. In western Bay of Bengal, this group contributed 7.74% (by number) and 9.33% (by weight) to the total catch. Alopias pelagicus, Carcharhinus limbatus, Alopias superciliosus and Carcharhinus falciformis were the dominant species of pelagic sharks observed in the Indian seas. Time series analysis of hooking rates revealed drastic decline in the abundance of pelagic sharks in the Arabian Sea as well as Bay of Bengal. © 2015, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.


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.


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.


Chembian A.J.,Cochin base of Fishery Survey of India | Mathew S.,Cochin University of Science and Technology
Indian Journal of Fisheries | Year: 2011

The area west of Kollam (38-51 m depth) and south-west of Cochin (38 - 45 m depth) seems to be the preferred region for spawning of the pharaoh cuttlefish Sepia pharaonis along the south-west coast of India. Juveniles appear to stay for some time in the spawning ground and then undertake offshore migration towards relatively deeper areas of the Wadge Bank in 117-132 m depth range. This migration appears to take place via west of Vizhinjam in the depth range of 60 - 86 m. Fecundity varies from 146 to 1400 eggs, depending upon the size of the animal. S. pharaonis appears to spawn intermittently with group-synchronous ovulation. Spawning appears to be monocyclic and egg-laying occurs in separate batches during the spawning period. Egg capsules are either inserted in to the muddy substratum or fastened on the preferred objects apart from entangling with each other.


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.


Varghese S.P.,Cochin Base of Fishery Survey of India | Unnikrishnan N.,Cochin Base of Fishery Survey of India
Marine Biodiversity | Year: 2015

Documentation of fish parasites is important in describing the biodiversity of a given water body. In this study, the first record of metazoan parasite fauna of long snouted lancetfish (Alepisaurus ferox) and swordfish (Xiphias gladius) of the eastern Arabian Sea is presented. Three cestodes (Pelichnibothrium speciosum, Tentacularia coryphaenae and Hepatoxylon trichiuri) and one trematode (Botulus microporus) were collected from the lancetfish. Parasite prevalence was 98.04 % and the average intensity was 9.58. In the swordfish, all the samples were infected, and the average parasite intensity was 51.4. Five cestodes (Hepatoxylon trichiuri, Fistulicola plicatus, Nybelinia bisulcata, Nybelinia lingualis and Tentacularia coryphaenae), at least two species of nematodes (Hysterothylacium incurvum and unidentified nematodes), one species of copepode (Pennella instructa), and a trematode (Hirudinella ventricosa) were collected from the swordfish. © 2015 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg


Samplings were conducted in fifteen stations in the Wadge Bank (lat. 07°07'N to 07°58'N and long. 76°55' E to 77°54'E) along the south-west coast of India for collecting egg capsules of Raja miraletus. Among the 15 stations covered, egg capsules of R. miraletus were observed only at three stations. A total of 119 egg capsules were collected from the area (lat. 07°21'N to 07°29″N and long. 76°55' E to 77°04'E), at the depth range of 112 -123 m indicating this area as the probable spawning ground of the species along the south-west coast of India. Only two of the egg capsules collected had embyo inside. The ratio of unhatched egg capsules to the number of empty capsules found during the survey indicates that, the terminal period of incubation may be in the month of May.

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