968 resultados para fish conservation


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At head of title: Illinois resource management.

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The paper critically examines the trend in fish production in Nigeria. The problem of excessive mismanagement and lack of attention by relevant agencies are still common place in inland water bodies. The paper discusses these mismanagement practices which are non compliance with the existing rules and regulations on good fishing methods, uncontrollable, unorthodox and obnoxious fishing practices, destruction of the natural breeding grounds and the collapse of the fishery due to massive over fishing. The challenges posed by the fishing methods as well as the effect of different gears and mechanization of fishing crafts on fish production are discussed. The paper recommends ways to increase domestic fish production in inland water bodies, which include a well planned strategy of restocking the existing reservoirs after careful scientific study, enforcement of the existing laws and regulation based on community participation. Training of stakeholders on the code of practice for responsible fisheries (CPRF), extension of subsidies to fisher folks, the traditional practices, which encourage the adherence to close season and other fish conservation and utilization strategies, are also advocated

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Wales is important for fish conservation in Britain. In much of Wales, atchments are small (median catchment size = 121 km2 ) and frequently eparated by areas of upland (> 600 m altitude), creating a highly agmented habitat for freshwater fish. Consequently, fish communities onsist mainly of diadromous species such as trout, eel and sticklebacks hat were able to recolonise freshwaters via the sea following the retreat of he ice sheets ca. 10 000 years BP. This review aims to (i) update the former work of Lyle and Maitland, taking into account new National Nature Reserves (NNRs)and additional data collected since 1991; (ii) assess the different fish communities represented on Welsh NNRs with respect to their naturalness; (iii) examine the use of NNRs for angling; (iv) evaluate opportunities for expanding the NNR series to conserve fish populations of conservation importance. The paper provides a table of freshwater fish occurrence by water body in Wales.

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In rural Cambodia, fish is a source of food and income to millions of people. However, there has been a real threat to fish populations in natural wetlands due to the degradation of aquatic biodiversity and habitat, illegal fishing, increase of population and demand for fish, and the use of harmful pesticides for agriculture. The Rice Field Fisheries Enhancement Project (RFFEP) seeks to rebuild and protect the fish populations through innovative methods. The project works with communities to sustainably strengthen the rice field fisheries near their villages by improving protected habitats called "community fish refuges". This handbook characterizes rice field fisheries that are connected to community fish refuges. Community fish refuges are designated fish conservation areas promoted by the Fisheries Administration of the Royal Cambodian Government. It also examines the characteristics of rain-fed rice field ecosystems that are connected to community fish refuges in order to further refine descriptive criteria and better understand potential benefits and management strategies.

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A discussion is presented on the topic of maintaining genetic diversity in aquatic ecosystems, considering the various threats caused by irreversible damage or loss to the environment. The current situation in aquaculture and future prospects regarding the conservation and protection of endangered species are outlined, describing the case of tilapias in Africa as one particular example of fish conservation.

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Following a general outcry by the population riparian to the Ugandan portion of lake Albert about dwindling fish catches, there was concern both from the FAO Country representative in Uganda and the government of Uganda on the state of the fisheries of this lake. The FAO representative accompanied by an official from the Uganda Fisheries and Fish Conservation Association (UFFCA) visited the lake in July 1999 (Appendix I). The Ugandan minister of state in charge of the Fisheries sector also visited the lake in November 1999 (Appendix II). The two were in common agreement that the lake was in a stocks crisis and there was need for remedial measures. It was therefore deemed necessary to initiate a technical report updating the present state of the fisheries resources of this lake. An agreement was thus signed between the author and the Food and Agricultural Organization of the United Nations - Sub-Regional Office for Southern Africa in Harare, to undertake this exercise.

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Artificial interspecific hybrids between large scale loach P. dabryanus and tetraploid pond loach M. anguillicaudatus (Cobitidae, Cypriniformes) are viable. To detect the occurrence of possible natural hybridization, genetic analyses by using microsatellite markers were performed for natural populations of large scale loach and pond loach, the reciprocal laboratory hybrids, and "supposed hybrids" with ambiguous morphology. The fertility of the artificial hybrids was also tested. At one diagnostic microsatellite (Mac50), one out of 20 "supposed hybrids" was identified to be F-1 hybrid between the two loach species because it had the same genotype as that of the laboratory hybrids. The triploid hybrids between the two species were confirmed to be female-sterile. The results show that rare hybridization has occurred between diploid large scale loach and tetraploid pond loach in nature although it may have little effect in genetic introgression. This study is helpful for fish conservation and encourages further investigation on natural hybridization and introgression of loaches.

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Salting have been a very utilized fish conservation method, however only in the last years the basic mechanism involved in salting fish has been understood. The objectives of this study were determine the addition in brine salt of rosemary leaves, rosemary extracts and tocopherol, and your action in the followed parameters: water activity (Aw), moisture, ash, salt content and TBARS. The results showed that the addition of antioxidants was difficulted the salt absorption, however didn't have differences between rosemary or tocopherol use. In the salting time of 3 hours the values of Aw and salt levels, was respectively: 0.77±0.01 and 14.42±1.69. for control treatment; 0.85±0.02 and 9.09±1.39for rosemary filtrate; 0.78±0.03 and 10.63±0.69 rosemary without filtrating and 0.85±0.02 and 11.96±1.78 tocopherol, showed that didn't grow indigenous bacterias. Lipid oxidation was evaluated by TBARS and the results showed the oxidative effect of salt and the pro oxidant effects of alls antioxidants used in brine salting.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Table of Contents: What’s Melting: Togiak Refuge Sizes Up Its Glaciers, page 3 Focus on Fish Conservation, pages 10-15 Whatever happened to…, pages 16-17 Wildlife Cooperatives, page 20

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1900/02 and 1902/04 contain also "A list of the native fishes of Illinois, with keys [by] Thomas Large."

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Title Varies: 1879/80-?, Reports of the State Fish Commission of Illinois; 1883/84, Report of the Illinois State Fish Commission; 1884/86-1894/96, Report of Board of Illinois State Fish Commissioners; 1896/98, Report of the Illinois State Fish Commissioner; 1898/1900, 1904/06-?, Report of State Fish Commissioners; 1900/02-1902/04, Report of State Board of Fish Commissioners

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Wild salmon stocks in the northern Baltic rivers became endangered in the second half of the 20th century, mainly due to recruitment overfishing. As a result, supplementary stocking was widely practised, and supplementation of the Tornionjoki salmon stock took place over a 25 year period until 2002. The stock has been closely monitored by electrofishing, smolt trapping, mark-recapture studies, catch samples and catch surveys. Background information on hatchery-reared stocked juveniles was also collected for this study. Bayesian statistics was applied to the data as this method offers the possibility of bringing prior information into the analysis and an advanced ability for incorporating uncertainty, and also provides probabilities for a multitude of hypotheses. Substantial divergences between reared and wild Tornionjoki salmon were identified in both demographic and phenological characteristics. The divergences tended to be larger the longer the duration spent in hatchery and the more favourable the hatchery conditions were for fast growth. Differences in environment likely induced most of the divergences, but selection of brood fish might have resulted in genotypic divergence in maturation age of reared salmon. Survival of stocked 1-year old juveniles to smolt varied from about 10% to about 25%. Stocking on the lower reach of the river seemed to decrease survival, and the negative effect of stocking volume on survival raises the concern of possible similar effects on the extant wild population. Post-smolt survival of wild Tornionjoki smolts was on average two times higher than that of smolts stocked as parr and 2.5 times higher than that of stocked smolts. Smolts of different groups showed synchronous variation and similar long-term survival trends. Both groups of reared salmon were more vulnerable to offshore driftnet and coastal trapnet fishing than wild salmon. Average survival from smolt to spawners of wild salmon was 2.8 times higher than that of salmon stocked as parr and 3.3 times higher than that of salmon stocked as smolts. Wild salmon and salmon stocked as parr were found to have similar lifetime survival rates, while stocked smolts have a lifetime survival rate over 4 times higher than the two other groups. If eggs are collected from the wild brood fish, stocking parr would therefore not be a sensible option. Stocking smolts instead would create a net benefit in terms of the number of spawners, but this strategy has serious drawbacks and risks associated with the larger phenotypic and demographic divergences from wild salmon. Supplementation was shown not to be the key factor behind the recovery of the Tornionjoki and other northern Baltic salmon stocks. Instead, a combination of restrictions in the sea fishery and simultaneous occurrence of favourable natural conditions for survival were the main reasons for the revival in the 1990 s. This study questions the effectiveness of supplementation as a conservation management tool. The benefits of supplementation seem at best limited. Relatively high occurrences of reared fish in catches may generate false optimism concerning the effects of supplementation. Supplementation may lead to genetic risks due to problems in brood fish collection and artificial rearing with relaxed natural selection and domestication. Appropriate management of fisheries is the main alternative to supplementation, without which all other efforts for long-term maintenance of a healthy fish resource fail.