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Title: Factors affecting the dispersal of coarse fish
Author: J.D. Bolland
Author: I.G. Cowx
Author: M.C. Lucas
Author: Environment Agency
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_1240, Representation ID: 405, Object ID: 2451
Habitats for fish in lowland rivers in England and Wales have been extensively modified for flow regulation purposes, including milling, navigation, land drainage and flood prevention. These modifications have degraded fish habitats and restricted the ability of fish to move between them, leading to changes in fish communities. These fish habitats will require mitigation and restoration in order to meet environmental objectives, notably the Good Ecological Status required under the European Commission’s Water Framework Directive. Legislation also requires that new schemes avoid adverse effects on biota, including fish. However, our understanding of the factors causing these changes and how best to rehabilitate rivers remains poor. In addition, future challenges, notably climate change and the consequent changes in flow and temperature regimes, may exacerbate these problems. This project describes patterns of lateral and longitudinal movement and the utilisation of various habitats by fish in relation to flow, temperature and season. It also examines losses of fish as a result of their becoming stranded in floodplains following overtopping of floodbanks and the subsequent isolation. Field studies were condcuted on three English rivers: the River Ouse in Yorkshire; the River Trent near Nottingham; and the River Roding, a small tributary of the Thames in Essex. These field studies employed a variety of techniques, including some new technologies. There was therefore a need to demonstrate that the effects of these techniques on fish mortality and behaviour would not significantly influence the results. Trials of tagging methods on small coarse fish were thus undertaken under controlled conditions. This project has demonstrated the links between flows and habitat in lowland rivers and both the lateral and longitudinal movements of coarse fish. It also makes a number of key recommendations for future research and for management action to support Good Ecological Status in English and Welsh lowland rivers.
Publisher: Environment Agency
Subject Keywords: FisheriesFlood defence structuresWater resourcesEnvironmental managementSustainable developmentNature conservationCoarse fishesRiver fisheriesWater levelsRiversHabitatsPopulation
Geographic Keywords: Ouse (Yorkshire)Trent (England)Roding
Extent: 154
Total file downloads: 372

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