125 research outputs found

    Variation in biochemical composition during gonad maturation of the tropical abalone Haliotis varia Linnaeus 1758 (Vetigastropoda: Haliotidae)

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    Biochemical changes in the body components during gonad maturation of the tropical abalone Haliotis varia were investigated using wild collected specimens from the Gulf of Mannar, on the southeast coast of India. The gonadosomatic index (GSI) and the hepatosomatic index (HSI) showed negative correlations throughout the study period as well as during the progression of gonad maturation stages. The highest GSI for both the sexes were in the ripe stages followed by late maturing stages. The HSI ranged from 2.97 to 6.71 in females, and 3.55 to 5.09 in males. Among the biochemical components analysed, lipid and carbohydrate contents showed significant variations in the different tissues of H. varia during the progress of gonad maturation. The highest protein content was in the foot muscle and the lowest was in the digestive gland. Total lipids in the ovary were always higher compared with that of the testis and the values ranged from 12.60 to 26.49%, registering the highest value in the ripe ovary. Gonad carbohydrate content was lower when the lipid content was higher, suggesting the conversion of carbohydrate to lipids. The present study demonstrates the role of nutrient translocation between body parts as an essential part of the reproductive physiology of abalone

    Gonad maturation of the tropical abalone Haliotis varia Linnaeus 1758 (Vetigastropoda: Haliotidae)

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    Gonad development of the tropical abalone Haliotis varia Linnaeus, 1758 from the Gulf of Mannar, southeast coast of India, was studied through the observation of gonad histology and analysis of gonadosomatic index. The sequence of gametogenesis was similar to previously described tropical haliotids. Gonad maturation stages were assigned to six categories and the details of different stages documented. Pre-vitellogenic oocytes were abundant in the early and late maturing ovary and were attached to the connective tissue tubules by their stalks. Vitellogenesis began when the primary oocytes reached 50 μm in diameter culminating in ripe oocytes of 180 ± 20 μm in diameter. All six gonad maturity stages were observed during the 14-month study period suggesting that gametogenesis was continuous throughout the year. The breeding season extended from December to February with asynchronous gonad development. Since active gametogenesis in this species was observed in all months, mature specimens could be produced throughout the year by induced maturation which would facilitate hatchery production

    Economic evaluation of mud crab farming under different production systems in India

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    Apart from penaeid shrimp culture, crab farming and fattening and other several diversified aquaculture practices are now emerging as viable ventures in India. About 11 types of crab products are being exported from India with an average unit value realization of US3.73kg1,pinpointingitsimportanceintheforeignexchangeearnings.Aneconomicevaluationofmudcrabculture,fatteningandfatteningwithcompositecultureofshrimp/finfishhasbeenattemptedinthispaper.Themajoroperatingcostwasthatofseedanditwashigherforcrabfattening(87shrimpfarming.AnnualprofitobtainedwasUS 3.73 kg- 1, pinpointing its importance in the foreign exchange earnings. An economic evaluation of mud crab culture, fattening and fattening with composite culture of shrimp/finfish has been attempted in this paper. The major operating cost was that of seed and it was higher for crab fattening (87% of the total operating cost). Feed costs were very low compared to that of shrimp farming. Annual profit obtained was US 22812.5 ha-1 year-1 for culture and US$ 30820.8 ha-1 year-1 for fattening. Economic indicators such as net profit, rate of return, pay back period and breakeven price indicate that crab fattening/culture is much more profitable than any other coastal aquaculture operations currently in practice, provided hatchery production is established in the country to ensure adequate supply of mud crab seeds

    Marine Finfish Resources of India: Distribution, Commercial Exploitation, Utilization Pattern and Trade

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    Seafood is high on the global trade agenda and has become particularly relevant in the light of the entry of fisheries into the WTO process (following WTO Doha Ministerial Conference in December 2002). International trading regimes are changing, with more open market access but with EU, US and other developed countries taking increasingly stringent measures for seafood safety. Changes in market access are likely to have significant implications for poor producers, and costs of implementation of international fisheries agreements, such as WTO sanitary and Phytosanitary (SPS) measures, HACCP standards, and market-driven labeling schemes may reduce livelihood options through barriers for participation of poor people. Liberalization of economies coupled with increasing demand for value added products and other product diversifications has resulted in structural changes of seafood industry in the last decade. Indian seafood exports declined to 1.89billionfrom2.10billiondollarsduring200708.TheglobalfinancialmeltdownseemstohavetakenitstollontheexportofmarineproductsfromIndiawiththebusinessrecordinga10percentslumpto1.89 billion from 2.10 billion dollars during 2007-08. The global financial meltdown seems to have taken its toll on the export of marine products from India with the business recording a 10 per cent slump to 1.9 billion for the year 2007-08. The country may even fall short of its target of $2 billion set for 2009, reports which was hit mainly due to economic recession in Europe and America, which are the major importers of marine products from India. The provisions under the various WTO agreements are expected to have an impact on the different dimensions on the Fisheries sector

    Collection of Data for Fishery Biology Studies and Fish Stock Assessment

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    Basic objective of fisheries research is to provide ample information on the status of fish stocks. This information is collected through various sampling procedures and the data are used to provide advice on the sustainable management of fish stocks, upon which the entire fishing industry depends. There are two main sources of data collected and used in fisheries research. These can be divided into fishery independent and fishery dependent data. The first usually involves monitoring the changes in distribution over time in the relative or absolute abundance of fish populations using vessel based surveys in a way that is not subject to the biases inherent in commercial fishery data. The collection and accurate interpretation of both fishery dependent and fishery independent data are of fundamental importance to our understanding of the fished species. Both are needed to gain an understanding of the magnitude of localized changes in fish communities, landings and productivity of the resource. Fishery dependent information involves collection of catch and effort data (CPUE) as well as biological sampling from commercial fisheries. CPUE data are usually collected from logbooks or using direct observation at the site of landings. The underlying assumption is that changes in CPUE accurately reflect changes in the abundance of the fish stocks

    Training Manual on Advances in Marine Fisheries in India

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    Training Manual on Advances in Marine Fisheries in Indi

    Diversity and exploitation status of demersal fishery resources in India

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    Fisheries are an important source of income and means of livelihood in developing countries, particularly in rural areas. Estimates by the Food and Agricultural Organisation indicates that capture fisheries employ over 27 million people worldwide, of which 85% live in Asia. Marine fisheries play an important role in food security and nutrition in developing countries. There is serious concern about the state of marine fisheries worldwide. While over-fishing is likely to have been the major cause of the serious setbacks, these have probably been exacerbated by habitat degradation. Fisheries sector plays an important role in the overall socio-economic development of India. The fisheries sector contributed 76,913 crores to the GDP during 2009-10 which is 0.96 per cent of the total GDP at factor cost and 5.4 per cent of the GDP at factor cost from agriculture forestry and fishing (Zacharia and Najmudeen, 2013). During 2015-16, the export of marine products from India reached over 9.45 lakh tonnes valued at Rs.30,421 crores and US$ 4.688 billion (MPEDA, 2017). India is one of major fish producing countries in the world contributing over 3 per cent of both marine and freshwater fishes to the world production (Srinath and Pillai, 2006) with third position in capture fisheries and second in aquaculture. India has an Exclusive Economic Zone (EEZ) covering a total area of 2.02 million sq. km, i.e., 0.86 million sq. km on the west coast including the Lakshadweep Islands and 1.16 million sq. km on the east coast, including the Andaman and Nicobar Islands and a continental shelf of half a million sq. km (Vivekananadan et al., 2003)

    Classification of Exploited Demersal Finfishes of India: Pigface breams, lizardfishes and eels

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    Demersal fishes are those fishes which live and feed on or near the bottom (the demersal zone) of seas . They occupy the sea floors, which usually consist of mud, sand, gravel or rocks. In coastal waters they are found on or near the continental shelf, and in deep waters they are found on or near the continental slope or along the continental rise. In India, demersal finfishes contribute about 26% to the total marine fish landings of the country, which is dominated by perches, croakers, catfishes, silverbellies, elasmobranchs, lizardfishes, flat fishes, pomfrets etc., in order of abundance. Most of the demersal finfishes in India are exploited by mechanised trawlers

    Seed production and juvenile rearing of the tropical abalone Haliotis varia Linnaeus 1758

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    Spawning, larval and juvenile rearing of the tropical abalone Haliotis varia L. were studied. Brood stock abalone were induced to spawn by exposure to air for 2 h at 27 °C. Female abalone spawned a mean of 76,530 eggs. Fertilised eggs measured 180 μm in diameter. Seventy percent survival was obtained during larval rearing. Larvae passed trochophore, veliger, gliding and creeping stages and were induced to settle on a mat of diatoms containing Nitszchia sp. and Navicula sp. The larval rearing period of H. varia ranged from 4 to 6 days at 27 °C. The settled spat vigorously fed on the diatom mat until the 50th day of postfertilisation and coralline red algal film, until the 70th day of postfertilisation. First respiratory pore was formed on the 27th day of postfertilisation. Juvenile abalones were reared on three algal diets such as coralline red algae, green filamentous algae and Ulva lactuca from the 71st to 200th day of postfertilisation. Those fed with coralline algae showed best and consistent growth. Shell colour of juveniles was affected by diet. The present study on the production of juveniles in the hatchery is a baseline information to initiate abalone aquaculture in India and to help augment the natural population

    Taxonomy of Exploited Demersal Finfishes of India: Lizardfishes, Pigface breams, Eels, Guitar fishes and Pomfrets

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    Demersal fishes are those fishes which live and feed on or near the bottom of seas. They occupy the sea floors, which usually consist of mud, sand, gravel or rocks. In coastal waters they are found on or near the continental shelf, and in deep waters they are found on or near the continental slope or along the continental rise. In India, demersal finfishes contribute about 26% to the total marine fish landings of the country, which is dominated by perches, croakers, catfishes, silverbellies, elasmobranchs, lizardfishes, flat fishes, pomfrets, etc., in order of abundance. Most of the demersal finfishes in India are exploited by mechanised trawlers
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