22 resultados para 3rd signal


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After 20 annual meetings it is worth to have a look back and to see how it has started. There has been very little collaboration on research projects between member institutes under the auspices of WEFTA, co-operation in more neutral areas of common interest was developed at an early stage. The area which has proved very fruitful is methodology. It was agreed that probably the best way to make progress was to arrange meetings at each laboratory in turn where experienced, practising scientists could describe in detail how they carried out analyses. In this way, difficulties could be demonstrated or uncovered, and the accuracy, precision, efficiency and cost of the methods used in different laboratories could be compared.

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Observations were made on crayfish burrows in five locations on the Great Ouse River. The burrow densities and the relative abundance of crayfish were observed. Also, laboratory experiments were carried out in order to study the characteristics and mechanisms of burrowing.

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The signal crayfish Pacifastacus leniusculus (Dana), a native of north-western North America, is now a common resident in some British fresh waters following its introduction to England in 1976 (Lowery & Holdich 1988). In 1984, signal crayfish were introduced into the River Great Ouse, the major lowland river in southern central England, where they have established a large breeding population. This study examines two sites near Thornborough Weir. For the measurement and description of home range a new eletronic microchip system and a modified capture-mark-recapture method were employed. Signal crayfish were marked or tagged to see if they gradually moved away from their burrows. This method proved to be successful for estimating population densities when a section of river is divided into several equidistant linear ”locations”.

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Signal crayfish (Pacifastacus leniusculus) have existed in the upper reaches of Broadmead Brook in Wiltshire since 200 individuals were introduced at West Kington in 1981. The population has expanded upstream and downstream since this introduction, however, giving rise to concerns that it may potentially threaten the native crayfish population further downstream. Signal crayfish can act as a vector of crayfish plague - a disease caused by the fungus Aphanomyces astaci Schikora which results in almost complete mortality to the native, white-clawed crayfish Austropotamobius pallipes. The native crayfish in Broadmead Brook have not yet succumbed to crayfish plague and are currently free of the disease. However, as signal crayfish appear to out-compete the native species, the native population could still be under threat. In this article, we highlight the findings of previous crayfish surveys on Broadmead Brook and describe work undertaken in summer 2001 to map the current distribution of native and signal crayfish. Finally, options for controlling the spread of signal crayfish are discussed.

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This book section aims to give an overview of the Stakeholders' Workshop taken at Mwanza (Tanzania) to evaluate the role and potentials of local stakeholders, in relation to the co-management of Lake Victoria's fisheries within the frame of the LVFRP.

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This paper comprises part of the so-called "3-beaches Survey" of the LVFRP. In Tanzania, this study has developed to examine two landing sites (Mwasonge and Ihale), and to chart the progress of the newly established Beach Management Units (BMU) at each beach, comparing one BMU against the other. The over-arching objective of this survey was to develop an understanding of the context in which Mwasonge's fishery exists. The study does so by examining the community's history, culture and beliefs, various other socio-cultural factors, their resources, society and economy, wealth and the community's perceptions of wealth. Importantly, the survey examines the community's institutions and its perceptions of fishing rules and changes within the fishery. All of these facets of community life are examined with the use of participatory Rural Appraisal tools, and the images that the study generated are reproduced herein.

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This manual has been produced by members of the national acoustics group (NAG) and represents the first in a series of outputs designed to promote co-ordination and consistency in Agency hydroacoustic surveys. It is designed as a field guide for Agency staff operating the SIMRAD EY500 portable scientific echosounder. It should be simplistic enough for the newcomer to EY500 to be able to set up and run a mobile hydroacoustic survey with some knowledge of the supporting theory. It should act as guidance for standardisation of survey procedures providing a concise list of settings and recommendations that can be used as a quick reference guide in the field. This manual condenses 5 years of practical experience of surveying fish populations using Simrad hardware and software for surveying large rivers and still waters throughout England and Wales. This document should be used as a companion to the manufacturers instruction manual and not act as a substitute for it.

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This is the first report from the South and West Cumberland Fisheries Advisory Committee meeting, which was held on the 3rd June 1974. The report includes sections on fishery byelaws, estimates for the anticipated income and expenditure on fisheries for the current year, and fish mortality. The section on fish mortality includes the details of a fish kill on the River Marron, gives points along the river where water was sampled, and the results of the analysis. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Eden Fisheries Advisory Committee meeting, which was held on the 3rd September 1974. The report looks at comments of the Regional Fisheries Officer on the report 'Taking Stock', and information including the aims of a report entitled 'Coarse Fisheries'. The report also includes sections on the summary of the stocking carried out from Holmewrangle hatchery, biological work undertaken on the Rivers Liddel, fishery prosecutions, and fish mortalities. This section includes information on the date, location, extent of the kill and the cause. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 3rd November 1975. The report contains information on the proceedings of the Local Fisheries Advisory Committee and recommendations for these committees, proposed Coarse Fish Unit, netting on the Solway Firth, fishing licence duties, fisheries improvement works on the River Leven and fishing at Jumbles Reservoir. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Eden Fisheries Advisory Committee meeting, which was held on the 3rd December 1974. The report looks at information on the Water Bailiffs establishment, including the organisation and the duties of both the Fisheries Inspector and the Senior Bailiff. It also includes the comments from the Regional Fisheries Officer on the report on 'Coarse Fisheries'. Also covered is the report by the Unit Fisheries Officer on fisheries activities. This includes biological work carried out including information on an invertebrate bottom sampling programme at 50 sites on the Eden and its tributaries, fish mortalities, information on the fishing of migratory fish, trout and coarse fish, hatchery work and fisheries prosecutions. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 3rd May 1976. The report contains information on the regional fisheries organization, the review of the Water Industry in England and Wales, fisheries improvement work on the River Leven, Mitton Hatchery, new code of fishery byelaws, proposed byelaws (Coniston) and temporary licences. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the South and West Cumberland Fisheries Advisory Committee meeting, which was held on the 3rd April, 1978. It covers information on Eskett Quarries, fisheries income and expenditure, British Steel Corporation's works at Workington effluent disposal and terminated angling leases. It also includes the report by the area fisheries officer on river conditions and fishing, migratory fish movements and Holmwrangle hatchery. Included in this report is also pollution incidents, fish disease and Yearl Weir fish counter. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Lune, Wyre and Furness Fisheries Advisory Committee meeting, which was held on the 3rd July, 1978. It covers information on the monitoring of radioactivity in migratory fish, fishing offences and prosecutions, the income from sale of rod and line licences, the review of discharge consent conditions, illegal netting, the Morecambe and Heysham sewerage scheme and fish counting work. It also covers the report by the area fisheries officer on river conditions and fishing for Lune, Furness, Wyre and tributaries. Also covered in the report is information on migratory fish movements, fish monitoring stations, Middleton hatchery, fish mortalities, fish diseases, biological work and stocking numbers of brown trout, rainbow trout and coarse fish by the Angling Associations. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Eden and District Fisheries Advisory Committee meeting, which was held on the 3rd April, 1979. It includes the information on the meeting about the possible reduction of haaf netting on the Solway Estuary. Also covered is the report by the area fisheries officer on fisheries activities which comments on river conditions and fishing for salmon, sea trout and coarse fish and an update on Holmwrangle hatchery including mortalities due to water quality and gill infections in brown trout. It also looks at fish disease, research work and data of monthly salmon and migratory trout catches on rod, line, nets and fixed engines for the 1978 season. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.