Bibliography of Indian Ocean scombroids

Bibliography of Indian Ocean scombroid

Drift gill net fishery for large pelagics at Cochin - A case study on by-catch of pelagic sharks

In India, the elasmobranchs contributed on an average 60,8(X) t during 1986 to 1999 forming 2.7% of the total marine fish landings. The production varied from 50,000t in 1990 to a highest of 75,(X)0 t in 1998. The sharks dominated forming 62.4%, followed by rays (33.5%) and skates the rest. The west coast accounted for 55.5% and east coast 44.5%. The highest contribution of 30.2% was from Gujarat followed by Tamilnadu (26.2%). The drift gillnets, sharing 48.5% of the production, was the major gear, followed by trawls (31.5%) and hooks and line (6.1%). Since the drift gillnets (DGN), apart from the scombroids, exploit a variety of larger pelagics, a case study of the shark fishery by the gear at Kochi was made based on the data from 1979 to 1999 and the results are presented her

Billfish fishery along the Indian coast with special reference to the Indo-Pacific sailfish Istiophorus platypterus (Shaw and Nodder 1792)

The landings of the billfishes along the Indian coast are showing an increasing trend since the 1990s and the estimated annual average landing during 2000-2007 was 4317 t. Drift gillnets-cum-longline/handlines operated from mechanized and motorized craft contributed to the catches. Along the east coast, peak catches occur during July-September and along the west coast during October-March. Istiophorus platypterus, Makaira spp. and Xiphias gladius were recorded, of which, the sailfish I. platypterus was the most dominant. Fork length of I. platypterus in the landings at Cochin Fisheries Harbour during 2005-2007 ranged from 80 cm to 300 cm and was dominated by the length group 120 to 250 cm. Although a by-catch, sailfishes are of considerable economic value and detailed studies on the fishery and biological aspects from the Indian EEZ are needed to assess stock status on a regional basis

Resource dynamics of the Indo-Pacific sailfish Istiophorus platypterus (Shaw, 1792) from the south-eastern Arabian Sea

The average billfish catch from the Indian EEZ during 2002-2007 was 4561 t which increased to 7856 t during 2008-2010, and nearly 80% of this was caught from the Arabian Sea by drift gillnet cum longline units. In the Indian Ocean region, billfishes (marlins, swordfish and sailfish) are considered as data deficient resource in the IOTC database. The sailfish Istiophorus platypterus (Shaw, 1792) was the major component of the billfish catch at Cochin Fisheries Harbour from where a fleet of gillnet cum longline units are regularly operated for oceanic fishes such as yellowfin tuna, seerfishes and pelagic sharks, besides billfishes. Length range of sailfish landed during 2005-2008 was 80-230 cm with inter-year variations in size groups contributing to the fishery. Length-weight relationship was estimated as 0.024 L 2.65 while growth parameters L∞ and K (annual) were estimated as 262 cm and 1.0 respectively. Diet preferences of fishes in the size range 180-227 cm indicated percent occurrence of fish as 81% followed by crabs (31%) and molluscs (25%). Trigger fishes (Balistes spp.) dominated the gut contents, followed by carangids like Selar spp. and Decapterus spp. Ova diameter of vitellogenic oocytes in ripe gonad with hydrated eggs ranged from 200 to 1300 μ with a major mode at 700 μ and a minor mode at 1200 μ, indicating hydrated eggs are released in batches at probably close intervals. Absolute fecundity from a ripe stage ovary was estimated as 20,97,481 eggs (1750 eggs per g ovary weight) with hydrated eggs forming about 31% of the total eggs, giving a batch fecundity of about 541 eggs per g ovary weight. Exploitation rate (E) indicated that although billfishes are considered as bycatch in the targeted fisheries for yellowfin tuna and pelagic sharks, the considerable number of fishing units operating for targeted tuna fishing has resulted in heavy fishing pressure (E=>0.6) on the sailfish resource during certain years

Fishery of yellowfin tuna Thunnus albacares (Bonnaterre, 1788) in the Indian EEZ with special reference to their biology and population characteristics

The fishery and population characteristics of yellowfin tuna, Thunnus albacares were monitored during 2006-'10. They were being caught as bycatch along the coasts of Indian mainland and island territories by several coast-based fishery for a long time. Their landings by coast-based fishery was very nominal (4,171 t year-1 average for 1985-2000) with considerable annual fluctuations until targeted fishery for the species developed during the last decade. This resulted in considerable improvement in landings to a peak of 37,963 t in 2007. The production declined thereafter due to shift in the target resource of these vessels from yellowfin tuna to billfishes and elasmobranchs. The annual average catch in oceanic fishery during 2006-'10 was 85,928 t. The coast-based fishery exploit mainly surface tunas in the outer shelf, adjacent oceanic areas and seamounts. At national level, the pooled catch was supported by 22 - 202 cm fishes with 66.3 cm as annual mean. Relatively large fishes of 40 to 202 cm with 83.4 cm as mean length and dominated by 58-102 cm groups supported the catch in line fishery. The gillnet fishery comprised 22 to 123 cm fishes dominated by 44-82 cm size and other gears landed 26 to 110 cm size fishes dominated by 42 to 80 cm size. Length at capture was 44.8 cm in gillnets, 60.3 cm in hooks and lines and 42.7 cm in other gears. The length at first maturity was 57.6 cm and optimum length for exploitation was 61.1 cm. They spawn round the year with peak during August-January. The mean relative fecundity was 4,36,330 ova per kg body weight and it varied with size of the fish. Study shows that stock of yellowfin tuna in Indian waters remain very healthy with large proportion of spawning stock biomass. Exploitation range of coastal based fishery being very limited and oceanic fishery concentrated mainly in international waters, large area of Indian EEZ remain unexploited by the country. Overall assessment of fishery scenario indicates possibility of large proportion of yellowfin tunas, especially larger ones remain inaccessible to Indian fishers and hence considerable scope for expanding the fishery

The emerging purse seine fishery for anchovy (whitebait) resources of the west coast of India

One of the most significant developments in the marine fisheries sector, in recent years is the large Scale introduction of purse seine fleets along the coasts of kamataka and kerala, for the commercial Exploitation of pelagic fish resources. This development may be considered as significant as the introduction of mechanized trawling in late fifties in indian waters for the exploitation of shrimp resources. It is, therefore, necessary to redeploy the purse seiners engaged in whitebait fishery, at the major centers spread over karnataka coast and to develop simultaneously at those bases infrastructure facilties capable of handling, storing, processing and marketing, realising the full potential of the purse seine fishery, in order to obtain remunerative prices for the huge whitebait catches landed during a short period of about three months

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)

Incidental by-catch of dolphins at fisheries harbour, Cochin with a note on their conservation and management in India

The present paper deals with the incidental bycatch of dolphins at Fisheries Harbour, Cochin. Catch statistics of dolphins lrom drift gillnets from January 1981 to December 1987 are given. Conservation and management of dolphins in India are stressed upon

Stock assessment of seerfishes in the Indian seas

The annual average catch of seerfishes from the Indian seas was 45,0601 during 1995-'99, which constituted 1.8% of the total marine fish catch in India. State-wise Gujarat (28.5%) was the major producer followed by Tamilnadu (15.8%), Maharashtra (15.4%), Andhra Pradesh (11.4%) and Kerala (10.5%). Gill net is the dominant gear in exploiting seerfish followed by trawl, hooks & line, boat seines, shore seines and purse seines. Among the five species, the kingseer Scomberomorus commerson (59.0%) and the spotted seer S. guttatus (35.1%) sustained the fishery, while the streaked seer S.lineolatus and the wahoo Acanthocybium solandri formed only a negligible portion of the fisher

Fishery, biology and population characteristics of longtail tuna, Thunnus tonggol (Bleeker, 1851) caught along the Indian coast

The longtail tuna, Thunnus tonggol, Bleeker, 1851 is an economically important species from commercial and recreational point of view. The species inhabit shelf and oceanic waters of tropical and temperate regions of the Indo-Pacific between 47° N and 33° S (Froese and Pauly, 2009) and generally occupy neritic areas of the oceans close to land masses (Yesaki, 1994)