999 resultados para Salmon fisheries.


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This is the Acid waters in North West England: The effect of liming agricultural land on the chemistry and biology of the River Esk, North West England report produced by National Rivers Authority in 1992. This report focuses on the study of Acid Waters in the North West Region of England, UK, which began in 1982 and sampling was completed in October 1990. This work was initiated because of the observation of the simultaneous mortality of adult and juvenile salmon and sea-trout in both the River Esk and adjacent River Duddon in June 1980. Investigations at that time indicated that an "acid episode" was the most likely cause of this mortality. A land use study indicated that a reduction in agricultural liming may have been a major factor in the development of acid episodes and consequent fish kills in the River Esk and River Duddon. However there was no evidence that the mortalities of salmonids in the early 1980's were due to a reduction in agricultural liming. They were due to some other phenomenon such as a period of intense acid deposition.

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Historic map of the River Lune Fishery District.

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This is the Water Resources in West Cumbria November 1976 report produced by the North West Water Authority. The report focuses on the provision of additional supplies of water in West Cumbria. In certain areas of West Cumbria difficulties arose in meeting peak demands. Moreover British Nuclear Fuels Ltd. (B.N.F.L) required additional water supplies. The area under consideration forms the western edge of the Lake District National Park and all the sources considered in this report, apart from the aquifer in the immediate vicinity of Calder Hall, lie wholly or partly within the National Park boundaries. The Rivers Ehen, Calder and Irt support migratory trout and salmon and are angling streams of a high quality. Amenity considerations therefore play an important part in determining the location and extent of any development.

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This is the report on the Effect of Abstraction on Fish and Fisheries presented at the 24th IFM Annual Study Course, The Changing Face of Fisheries September 1993 at Cardiff. Water is abstracted from rivers for a wide variety of uses and causing potential for conflicts between abstracters, fisheries and conservation interests, especially during natural low flows. It looks at the potential effects that flow reduction has over various stages of salmonids at various stages of their life history. The flow at the time of smolt migration has been found to be positively correlated with the number of returning adults, and flow is considered to be one of the most important environmental factors inducing salmonids to enter fresh water and ascend rivers. The importance of time series data on fish stocks and angling success together with models which ultimately relate discharge to standing stock are discussed in relation to the setting up of Minimum Acceptable Flows.

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This is the assessment of the flow requirements for upstream migration of salmonids in some rivers of North West England produced by the North West Water Authority in 1985. This report focuses on the automatic fish counters operating on the resistivity principle used for several years in North West England. This report aims to investigate the flow requirements for upstream migration of salmon and migratory trout. The data obtained confirmed that during summer months most fish movement occurs in the higher range of the available flows, but the migration flow range varied from year to year, depending on prevailing river levels. Of the other environmental variables measured, only water temperature and incident light intensity appear to have any direct association with fish movement. Information on migration flow ranges were used in conjunction with computer simulations of the effects of abstraction proposals on historical flows to assess the implications of these proposals for migratory fish.

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This is the episodic variations in stream water chemistry associated with acid rainfall and run-off and the effect on aquatic ecosystems, with particular reference to fish populations in North West England produced by the North West Water Authority in 1985. This report looks at the biological, physical and chemical information collected over a five year period from over 100 sites on upland streams in the North West Region of which drained rocks of low buffering capacity. In both Lake District and South Pennine sites striking differences were found between the composition of invertebrate communities inhabiting acid-stressed and less acid-stressed streams. Electric fishing surveys showed that acidic streams (geometric mean pH <5.5) generally had abnormally low densities of salmonids ( < 0 .2m2) and that 0+ fish were very few or absent. The latter indicates recruitment failure. Salmon were more sensitive than trout to low pH.

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This is the 2001 annual report on fisheries in the North West produced by the Environment Agency North West in 2002. This report has four main aims: to inform the Agency’s customers of developments within the Agency, to inform the Agency’s customers of the work carried out by the Agency, to publish information on the performance of fisheries and the Fisheries Department, and to be a source of future reference. The fisheries service is funded in the main by a mixture of rod licence income and government grant-in-aid. The latter has declined substantially since the mid 1990’s and we are increasingly reliant on licence income to fund fisheries work. The environment agency had managed to use some of this money to fund their Urban Fisheries Development Programme, (UFDP). This is aimed at delivering new or improved fisheries in areas where demand for fishing is high, but where available fisheries are few in number or of poor quality. This work is dependent on good co-operation with local angling clubs, councils and other interests.

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This is the Wetland resource evaluation and the NRA's role in its conservation: Resource assessment report produced by North West Water in 1982. In this report data from a variety of sources in river Leven and Leven estuary have been examined to determine if there was any objective foundation for the allegations and for the assertion that poor fish catches were related to discharges of industrial effluent to the estuary. Catches of salmon and sea trout from the Leven did not appear to have suffered any long term declines and year to year fluctuations did not appear to be any more extreme than in other North West rivers. Fish surveys did not show any marked differences in the diversity or distribution of fish between the Kent and Leven estuaries but catches of flounders were consistently lower from the Leven estuary. Analysis of fisheries statistics of landings of fish and shellfish from Morecambe Bay did not show any evidence of localised declines in catches from the Leven estuary. Results of laboratory experiments suggested that populations of bivalve molluscs might be more at risk from the effects of discharges to the Leven estuary than resident or migratory fish.

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This is the report on the strategic stock assessment survey of the Colton Beck catchment in 1994 with particular reference to salmonids in Colton Beck, River Ea, River Gilpin and Rusland Pool. This report forms one part of the third year of a triennial survey programme for the South West Cumbria and South Cumbria catchments. It was produced by the National Rivers Authority in 1994. Colton Beck had excellent densities of sea trout (Salmo trutta) and a small population of salmon (Salmo salar) in its lowest reaches. The total productivity was very good throughout the catchment. Stocking of sea trout fry in 1993 has enhanced the population with survivors through to parr probably adding to the scoring of double class A at two sites in the survey in 1994. Stocking was not undertaken in 1994, but the population appears to be maintaining itself at a very high level.