78 resultados para severity scale


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The state of Assam in northeastern India has an excellent sub-tropical climate for the development of fresh water fish culture in a variety of aquatic bodies. Aquaculture not only plays an important role in nutrition but also in the rural economy of the State. A pilot project conducted with a group of resource poor tribal farmers revealed that a production of about 1 800 kg/ha/yr could be achieved from small seasonal homestead ponds through integrated use of locally available biological resources. This implies an excellent opportunity for improving the rural economy through the development of small-scale fish culture enterprises. In this project, a greater emphasis was placed on improving the knowledge and skills of the farmers and their farming practices so that in the future they would be in a position to expand their activities with financial assistance made available locally. Aquaculture being a new activity in the area, this pilot project was only a start in acquainting the farmers with the practice and potential of aquaculture.

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A brief account of the evolution and structure of the marine fisheries of Senegal, West Africa, is presented, with emphasis on the small-scale subsector and on the major recommendations of an international symposium/workshop on this topic, held on February 1993 in Dakar.

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A description of the small-scale fisheries of the coastal pelagic and demersal resources off Kribi, Cameroon, is presented. The major fishing grounds are within the estuarine zone, an area of high productivity. Catch estimates of 19.5 t year super(-1) and 6.5 t year super(-1) were obtained for the pelagic motorized and nonmotorized canoes, respectively, while estimates of 11 t year super(-1) were obtained for the demersal motorized canoes. The social benefits from these fisheries are also discussed.

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The 1997 International Year of the Reef sees the release of ReefBase 2.0: a global database on coral reefs and their resources. It provides the most comprehensive and accessible repository of information to date. Containing information on over 7000 coral reefs in more than 123 countries, ReefBase 2.0 offers an extensive range of time-related data pertaining to coastal tourism, benthic environment ecology, fish population statistics, oceanography, socioeconomics, mariculture, and harvest activities. It also outlines the stresses causing reef degradation as well as management initiatives. Complemented by hundreds of digitized maps provided by the World Conservation Monitoring Centre (WCMC) and over 500 high quality photographs, ReefBase 2.0 is not only an essential tool for coral reef management but also an comprehensive guide for tourists, scuba divers and snorkelers alike. ReefBase has contributed substantially to the success of the International Coral Reef Institute (ICRI) and serves as the official database of the Global Coral Reef Monitoring Network (GCRMN), bringing together an increasing volume of data on coral reef health, management and significance to humanity, and making it widely available. Over the next five years, the information contained within ReefBase will be utilized as an instrument for developing coral reef health assessment criteria, sustainable management criteria, and providing continuously updated summaries of threats endangering coral reefs around the globe. This will be a strong basis for focused corrective action in an attempt to conserve coral reefs and properly manage their resources for future generations.

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The study compares the socioeconomic profile of fish and nonfish farming households in three different agroecological regions in Zimbabwe. Some of the direct socioeconomic factors that influence the adoption of small-scale fish farming in the areas are also identified.

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In Cambodia, women make up more than 65% of the adult population. They play a most important role in all spheres of social and economic activities. A recent investigation has shown that in small scale aquaculture, women have been found to contribute more than men in almost all activities. Details about this are discussed in this article.

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The findings are presented of a search conducted on traditional fishing gear design and construction using the ASFA database (1971-90) and the ICLARM Library and professional staff collections.

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The high demand for the stinging catfish (Heteropneustes fossilis) and declining wild stocks led the Centre for Aquaculture Research and Extension of India to look for methods for the culture of the species. This paper presents a low-cost, simple breeding technique developed and tested by the Centre that can be easily adopted by rural farmers.

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This paper describes the trials made with a simple portable canvas-tarpaulin tank system developed at the University Sains Malaysia for culture of hybrid catfish (Clarias gariepinus x Clarias macrocephalus) by Malaysia small scale farmers.

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This paper specifically examines the main determinants of women participation in income-earning activities in Peninsular Malaysian small scale fisheries.

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In this study we present new information on seasonal variation in absolute growth rate in length of coho salmon (Oncorhynchus kisutch) in the ocean off Oregon and Washington, and relate these changes in growth rate to concurrent changes in the spacing of scale circuli. Average spacing of scale circuli and average rate of circulus formation were significantly and positively correlated with average growth rate among groups of juvenile and maturing coho salmon and thus could provide estimates of growth between age groups and seasons. Regression analyses indicated that the spacing of circuli was proportional to the scale growth rate raised to the 0.4−0.6 power. Seasonal changes in the spacing of scale circuli reflected seasonal changes in apparent growth rates of fish. Spacing of circuli at the scale margin was greatest during the spring and early summer, decreased during the summer, and was lowest in winter or early spring. Changes over time in length of fish caught during research cruises indicated that the average growth rate of juvenile coho salmon between June and September was about 1.3 mm/d and then decreased during the fall and winter to about 0.6 mm/d. Average growth rate of maturing fish was about 2 mm/d between May and June, then decreased to about 1 mm/d between June and September. Average apparent growth rates of groups of maturing coded-wire−tagged coho salmon caught in the ocean hook-and-line fisheries also decreased between June and September. Our results indicate that seasonal change in the spacing of scale circuli is a useful indicator of seasonal change in growth rate of coho salmon in the ocean.

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In recent decades, hatchery-growout culture of oysters, Crassostrea virginica, and northern quahogs, Mercenaria mercenaria, has been commercially successful in Atlantic United States and oysters in Atlantic Canada. Culturists have not had success, as yet, with northern bay scallops, Argopecten irradians irradians. Large mortalities occur during the culture process, mainly because the scallops are relatively delicate and some die when handled. In addition, too little edible meat, i.e. the adductor muscle, is produced for the culture operation to be profitable. However, three companies, one in Massachusetts, one in New Brunswick, and one on Prince Edward Island, Canada, have discovered that they can produce bay scallops successfully by harvesting them when partially-to fully-grown and selling them whole. In restaurants, the scallops are cooked and served with all their meats (adductor muscles and rims) and also with the shells, which have been genetically-bred for bright colors. The scallop seed are produced in hatcheries and then grown in lantern or pearl nets and cages to market size. Thus far, production has been relatively small, just beyond the pilot-scale, until a larger demand develops for this product.

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Despite considerable conservation efforts, many reef fish fisheries around the world continue to be in peril. Many are vulnerable to overexploitation because they have predictable and highly aggregated spawning events. In U.S. Caribbean waters, fishery managers are increasingly interested in advancing the use of closed areas as a means for rebuilding reef fisheries, protecting coral reef habitats, and furthering ecosystem-based management while maintaining the sustained participation of local fishing communities. This study details small-scale fishermen’s views on the Caribbean Fishery Management Council’s proposals to lengthen the current Bajo de Sico seasonal closure off the west coast of Puerto Rico to afford additional protection to snapper-grouper spawning populations and associated coral reef habitats. Drawing on snowball sampling techniques, we interviewed 65 small-scale fishermen who regularly operate in the Bajo de Sico area. Snowball sampling is a useful method to sample difficult-to-find populations. Our analysis revealed that the majority of the respondents opposed a longer seasonal closure in the Bajo de Sico area, believing that the existing 3-month closure afforded ample protection to reef fish spawning aggregations and that their gear did not impact deep-water corals in the area. Whilst fishermen’s opposition to additional regulations was anticipated, the magnitude of the socio-economic consequences described was unexpected. Fishermen estimated that a year round closure would cause their gross household income to fall between 10% and 80%, with an average drop of 48%. Our findings suggest that policy analysts and decision-makers should strive to better understand the cumulative impacts of regulations given the magnitude of the reported socio-economic impacts; and, more importantly, they should strive to enhance the existing mechanisms by which fishermen can contribute their knowledge and perspectives into the management process.

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The annual catches of four small longliners operating off northeast Brazil from 1983 to 1997 were examined across different areas and locations. The total catch comprised tunas (30%), sharks (54%), billfishes (12%), and other fish species (4%). Fishing strategy and annual composition of catches showed large spatial and temporal variabilities with the dominant catches alternating among yellowfin tuna, Thunnus albacares; gray sharks, Carcharhinus spp.; and blue shark, Prionace glauca. Catches of blue and gray sharks showed a significant interaction among seamounts, with gray sharks occurring in maximum abundance around those seamounts that had relatively deep summits and low-sloping depth profiles. Results are discussed in terms of the various factors that may have influenced distribution of effort.

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Over the years, aquaculture has developed as one of the fastest growing food production sectors in Nepal. However, local fish supplies have been extremely inadequate to meet the ever increasing demand in the country. Nepal imports substantial quantities of fish and fish products from India, Bangladesh, Thailand, and elsewhere. Integration of pond aquaculture in existing crop-livestock-based farming system is believed to be effective in increasing local fish supply and diversifying livelihood options of a large number of small-holder farmers in southern plains (terai) and mid-hill valleys, thereby also increasing resilience of rural livelihoods. There is growing appreciation of the role of small-scale aquaculture in household food and nutrition security, income generation, and empowerment of women and marginalized communities. This book includes a total of 25 papers presented at the ‘Symposium on Small-scale Aquaculture for Increasing Resilience of Rural Livelihoods in Nepal’, held in Kathmandu on 5-6 February 2009. The papers cover technological, social, economic and environmental aspects of small-scale aquaculture development emerged from research and development initiatives of governmental, non-governmental and international research organizations in recent decad