A guide to the interpretation of sea trout scales

The overall purpose of this guide is to provide a manual for the collection and interpretation of sea trout scales. A brief introduction considers the advantages and disadvantages of using scales to determine age and growth. To ensure that scales are interpreted in a consistent manner, all major terms are defined and a standard system for age notation is proposed. The methodology for the collection, mounting and interpretation of scales is described in detail, and this is followed by a section on the back-calculation of lengths at different ages. Each topic is discussed critically. The final part of this guide is an atlas illustrating scales from a wide range of sea trout and including not only excellent "type-scales" but also difficult and impossible scales.

River Wyre salmon and sea trout spawning habitat restoration / creation project. Gravel enhancement schemes.

As part of an overall desire to maintain and improve the migratory salmonid population in the River Wyre, a project was commissioned to investigate remedial action which may improve and enhance spawning success and lead to an eventual improvement in the status of adult stocks. The report, titled "River Wyre Salmon and Sea Trout Spawning Habitat Restoration/Creation Project", concluded that usable spawning gravels appeared to be in short supply in the River Wyre catchment and may be the limiting factor influencing the returning adult stock, as juvenile nursery habitat was not found to be limiting. This report looks at gravel enhancement schemes to improve River Wyre salmon and sea trout spawning habitat restoration. It examines methods for gravel enhancement schemes: mechanical cleaning and construction of gravel addition structures. Includes sites figures of sites identified for enhancement.

Coarse and stillwater trout fisheries. Paper in evidence to the review of fisheries policy and legislation

This paper highlights the social and economic importance of coarse and stillwater trout fisheries and explains the UK Environment Agency's aim, its policies and processes, and its powers for managing and regulating these fisheries, concluding with reasoned proposals for change.

Comparison of six tag types in sea-trout tagging experiments in the Baltic Sea

In the international Baltic Sea trout tagging experiment 27 753 hatchery reared sea trout smolts were tagged in Denmark, Finland, Poland and Sweden in 1979 and 1980. The fish were tagged with the original Carlin tag, two modified Carlin tag types (Canadian and Finnish polythene), streamer and Floy tags and Polish tags attached with Monel metal wire. The tag returns were affected by the place of release and smolt quality. The best results were obtained in the case of tags attached with double wire or thread -original Carlin, Canadian and Finnish polythene. The poorest results were obtained with streamer tags.

An investigation into the effects of electric fishing equipment on salmon and sea trout within the area of the Lancashire River Board.

The report looks at experiments into electric fishing equipment and effects on salmon and trout within the Lancashire River Board. Experiments include obtaining information on voltage gradients, ascertaining what damage to fish of the larger size groups resulted from electric fishing, determining whether or not fractures could occur in coarse fish and brown trout,similar to those occurring in salmon and sea trout, and effects low temperatures have on electrofishing techniques.

The use of otolith morphology to indicate the stock structure of common coral trout (Plectropomus leopardus) on the Great Barrier Reef, Australia

We investigated the use of otolith morphology to indicate the stock structure of an exploited serranid coral reef fish, Plectropomus leopardus, on the Great Barrier Reef (GBR), Australia. Otoliths were measured by traditional one-and two-dimensional measures (otolith length, width, area, perimeter, circularity, and rectangularity), as well as by Fourier analysis to capture the finer details of otolith shape. Variables were compared among four regions of the GBR separated by hundreds of kilometers, as well as among three reefs within each region, hundreds of meters to tens of kilometers apart. The temporal stability in otolith structure was examined by comparing two cohorts of fully recruited four-year-old P. leopardus collected two years before and two years after a signif icant disturbance in the southern parts of the GBR caused by a large tropical cyclone in March 1997. Results indicated the presence of at least two stocks of P. leopardus, although the structure of each stock varied depending on the cohort considered. The results highlight the importance of incorporating data from several years in studies using otolith morphology to discriminate temporary and possibly misleading signals from those that indicate persistent spatial structure in stocks. We conclude that otolith morphology can be used as an initial step to direct further research on groups of P. leopardus that have lived at least a part of their life in different environments.

Conservation of the Nilgiri rainbow trout in India

Rainbow trout is one of the important exotic species that is well established in the upland waters of India. This paper presents the historical background of its introduction and the present status of the fish in the streams of he Nilgiri peninsula of India. The rainbow trout inhabits natural reservoirs and streams of the region as a self-recruiting population. The growth rate is reported to be relatively low and conflicting views about its taxonomic status have been reported. Successful crossbreeding of the Nilgiri rainbow trout with trout stocks from the Indian State of Himachal Pradesh has indicated the scope for utilizing cryopreserved milt as a mode of introducing new genetic material into the Nilgiri rainbow trout population. This paper outlines the requirement of ecological and genetic data to develop a strategy for management and reintroduction fresh stocks.

Effects of water quality in Bassenthwaite Lake on anglers' catches of salmon and sea-trout in the River Derwent

This is the report on the Effects of Water Quality in the Bassenthwaite Lake on Anglers Catches of Salmon and Sea-trout in the River Derwent April 1993 by the Institute of Freshwater Ecology. An analysis of the catch statistics for salmon and sea-trout in the Rivers Derwent and Cocker was undertaken in relation to available information on the algal water quality in Bassenthwaite Lake to test the hypothesis that poor catch returns were associated with a deterioration of water quality within the lake. Analysis of the catch statistics failed to reveal any correlation between water quality and catch returns for either species of fish and it is concluded that any water deterioration in Bassenthwaite Lake has not caused any major damage to the salmon and sea trout fisheries of the Derwent/Cocker system. This conclusion is supported by the analysis of the Windermere/Leven and Crake system, where no correlation could be found between lake water quality and downstream catches of migratory salmonid fish. However, the possibility still exists and such an effect might be detected by further field work on the macroinvertebrates and on the composition of potential salmonid spawning in the area.

Planting Sea Trout Ova 1952

Three men planting out Sea trout ova in a beck in North West England, UK, in 1952. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Brown trout habitat assessment on the River Bela catchment (as recommended by the strategic fisheries stock assessment task group 1995)

This is the Brown trout habitat assessment on the River Bela catchment produced by the Environment Agency North West in 1997. The Environment Agency (EA) and its predecessor the National Rivers Authority undertook strategic fish stock assessments in 1992 and 1995 on the River Bela catchment. These surveys found low numbers of brown trout {Salmo trutta) at some sites. Following this, habitat evaluation assessments were undertaken on the eleven poorest sites Factors probably responsible for declining trout populations on the three main tributaries of the Bela catchment include: Overgrazing by farm stock; Lack of suitable cover for parr; the absence of suitable spawning areas; existing potential of certain areas within the catchment not being utilised, due to poor dispersal. Habitat Improvement Schemes (H.I.S) are discussed and prioritised.

Report of 1996 survey of Trout Beck with particular reference to spawning gravel quality and invertebrates as a food source for salmonids

This is the Report of 1996 survey of Trout Beck with particular reference to spawning gravel quality and invertebrates as a food source for salmonids produced by the Environment Agency North West. Whilst the main River Derwent is quite a high profile salmon fishery, Trout Beck is not a significant fishery in its own right, but serves to maintain the genetic integrity of the wild populations of trout and salmon in the catchment by providing a unique habitat. This survey addressed the invertebrate food availability, and additionally looked at the substrate to try to determine whether the bed type might actually be unsuitable for spawning, especially in view of the previously mentioned silt inputs.