The Post-stocking Behaviour of Hatchery-reared Brown Trout (Salmo Trutta L.). PDF Download
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Author: James Ian Deverill
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: James Ian Deverill
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: James Ian Deverill
Publisher:
ISBN:
Category : Brown trout
Languages : en
Pages :
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Book Description
Stocking, transfer and introductions of hatchery-reared salmonids are commonly used to enhance recreational or commercial fisheries and to preserve or re-establish threatened populations (Cowx, 1994). Whilst a lot of effort has been directed toward understanding the production and stocking methods of hatchery-reared salmonids, relatively little is known about the post-stocking survival and behaviour of these fish (Hickley, 1994). In particular there is little available information concerning the post-stocking dietary habits, dispersionand behaviour of hatchery-reared brown trout; particularly following release into standing waters. Consequently, a study was instigated to examine the relative post-stocking dispersion and temporal changes in the diets of hatchery-reared brown trout released to support a commercial recreational fishery, Carron Valley Reservoir. Further laboratory studies examined if resident brown trout display a prior-resident competitive advantage overstocked conspecifics, if hatchery-reared brown trout display non-cost effective aggressive behaviour and the short-term changes in the feeding efficiency of naive hatchery-reared brown trout when experiencing novel prey. 1000 commercially produced hatchery-reared brown trout were marked with a subcutaneousalcian blue tattoo and released into Carron Valley Reservoir at the start of the 1999 fishing season. Stomach samples were taken from angler recaptured hatchery-reared fish along with consecutively captured resident brown trout. The diets of the two groups were compared to assess the relative post-stocking temporal changes in the diets of the hatchery-reared brown trout. This study found hatchery-reared brown trout to consume lower weights and numbers of prey, and they appeared to exhibit a preconditioned Hlook up dietary response to surface prey immediately following release than resident conspecifics. It was further observed that although hatchery-reared brown trout did not immediately adapt to natural diets, their relative foraging efficiency increased over the sample period. In laboratory experiments naive hatchery-reared brown trout further demonstrated the improved feeding efficiency with experience. 1000 commercially produced hatchery-reared brown trout were tagged with a combinationof Visible Implant (VI) and HFloy style tags prior to release during the 1998,1999 and 2000 fishing seasons. An angler survey programme was instigated to record the reported recapture positions of these tagged fish in order to assess the post-stocking gross dispersion patterns of hatchery-reared brown trout in Carron Valley Reservoir. A further 3 trout were radiotagged to elucidate the fine scale post-stocking dispersion of these fish. This study found hatchery-reared brown trout to disperse quickly from their respective release sites, although over a relatively restricted area. Individual hatchery-reared brown trout wereobserved to exhibit high levels of activity immediately following release, during which period they covered relatively large total distances within a relatively restricted area. In an artificial stream environment, established wild brown trout displayed a prior-resident competitive advantage over later introductions of both hatchery-reared and wild conspecifics. Established wild fish initiated more aggressive acts and maintained home stations closer to a point source of feed than introduced trout. Introduced hatchery-reared brown trout were more aggressive and exhibited a lower mean specific growth rate than simultaneously stocked wild conspecifics, suggesting that excessive expenditure of energy forunnecessary aggression may contribute to the poor post-stocking survival in hatchery-reared brown trout.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 152
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The international journal Ecohydrology & Hydrobiology (E&H) has been created to promote the concept of Ecohydrology, which is defined as the study of the functional interrelations between hydrology and biota at the catchment scale. Ecohydrology extends from the molecular level to catchment-scale processes and is based on three principles: • framework (hydrological principle) - quantification and integration of hydrological and ecological processes at a basin scale; • target (ecological principle) - necessity of enhancing ecosystem absorbing capacity and ecosystem services; and • management tool (ecological engineering) – the use of ecosystem properties for regulation the interplay between hydrology and biota. The journal encourages the submission of manuscripts which adopt an integrative approach to aquatic sciences, explaining ecological and hydrological processes at a river-basin scale or propose practical applications of this knowledge. It will also consider papers in other hydrobiological fields. Especially welcome are papers on regulatory mechanism within biocenosis and the resistance and resilience of freshwater and costal zones ecosystems. There is no page charge for published papers. All submitted papers, written exclusively in English, should be original works, unpublished and not under consideration for publication elsewhere. All papers are peer-reviewed. The following types of papers are considered for publication in E&H: • original research papers • invited or submitted review papers, • short communications
Author: Timothy J. Watkins
Publisher:
ISBN:
Category : Brown trout
Languages : en
Pages : 138
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Author: Heather A. Schongar
Publisher:
ISBN: 9781124241258
Category : Brown trout
Languages : en
Pages : 140
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Author: Bror Jonsson
Publisher: Springer Science & Business Media
ISBN: 9400711891
Category : Science
Languages : en
Pages : 720
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Destruction of habitat is the major cause for loss of biodiversity including variation in life history and habitat ecology. Each species and population adapts to its environment, adaptations visible in morphology, ecology, behaviour, physiology and genetics. Here, the authors present the population ecology of Atlantic salmon and brown trout and how it is influenced by the environment in terms of growth, migration, spawning and recruitment. Salmonids appeared as freshwater fish some 50 million years ago. Atlantic salmon and brown trout evolved in the Atlantic basin, Atlantic salmon in North America and Europe, brown trout in Europe, Northern Africa and Western Asia. The species live in small streams as well as large rivers, lakes, estuaries, coastal seas and oceans, with brown trout better adapted to small streams and less well adapted to feeding in the ocean than Atlantic salmon. Smolt and adult sizes and longevity are constrained by habitat conditions of populations spawning in small streams. Feeding, wintering and spawning opportunities influence migratory versus resident lifestyles, while the growth rate influences egg size and number, age at maturity, reproductive success and longevity. Further, early experiences influence later performance. For instance, juvenile behaviour influences adult homing, competition for spawning habitat, partner finding and predator avoidance. The abundance of wild Atlantic salmon populations has declined in recent years; climate change and escaped farmed salmon are major threats. The climate influences through changes in temperature and flow, while escaped farmed salmon do so through ecological competition, interbreeding and the spreading of contagious diseases. The authors pinpoint essential problems and offer suggestions as to how they can be reduced. In this context, population enhancement, habitat restoration and management are also discussed. The text closes with a presentation of what the authors view as major scientific challenges in ecological research on these species.
Author: U.S. Fish and Wildlife Service
Publisher:
ISBN:
Category : Fish culture
Languages : en
Pages : 716
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Author:
Publisher:
ISBN:
Category : Fish culture
Languages : en
Pages : 610
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Author: Lennart Nyman
Publisher:
ISBN:
Category : Fisheries
Languages : en
Pages : 536
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Author:
Publisher:
ISBN:
Category : Fisheries
Languages : en
Pages : 436
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