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The potential use of fish refuges to reduce damage to inland fisheries by fish-eating birds - VC0114

Cormorants can cause serious fish losses in inland fisheries; however, licensed shooting of cormorants (controlled by MAFF) is not always possible or appropriate and other methods of deterrence need to be explored. This study will aim to establish whether the use of refuges might offer an acceptable and effective technique for limiting losses of fish to cormorant predation. The study will be composed of 4 specific objectives outlined as follows, together with ways in which they might be achieved: 1. Implementation of a critical review of available information on fish behaviour, response of fish to predators and refuge design and application. In addition to literature sources, information will be obtained through consultation with appropriate experts, such as Environment Agency (EA) fisheries officers and fishery managers. Findings will be presented in a report; 2. Evaluation and description of the acceptability and practicality (including costs and potential benefits) of possible fish refuges under different circumstances. Findings from the review will form the basis for identifying potential refuge designs. Fishery managers will be consulted to investigate the acceptability and practicality of fish refuges across a range of scenarios. Fish species, circumstances and potential refuge designs appropriate for further investigation will be highlighted and selected; 3. Description of the extent to which potential refuge designs are used by different fish species, and whether usage is affected by the presence of cormorants. Potential refuge designs will be evaluated to allow an iterative process of design selection and improvement. Trial sites will be small stillwater fisheries regularly visited by cormorants. Various methods of assessing refuge use by targeted fish species (including trout, roach and carp) will be employed, including underwater cameras and direct observations from a boat. Acoustic telemetry techniques will be used for precise study of fish behaviour and movements with respect to refuge use. Field trials of refuges will be conducted during both winter and summer periods to assess seasonal changes in behaviour and use of refuges; and 4. Assessment of whether the foraging behaviour of cormorants is affected by the presence of refuges. During the refuge suitability trials, simultaneous data will be collected on the numbers and distribution of fish-eating birds present at the site and their feeding behaviour. Other variables such as human disturbance and environmental changes at trial sites will also be monitored. Data on bird numbers and behaviour will be compared with detailed fish behaviour records to determine whether there is any correlation between fish and bird behaviour. This will include the behaviour of the fish in the presence and absence of birds and the foraging behaviour of birds in relation to the refuges. Findings will be presented in reports.
Project Documents
• Final Report : The potential use of fish refuges to reduce damage to inland fisheries by fish-eating birds.   (175k)
Time-Scale and Cost
From: 2000

To: 2002

Cost: £217,066
Contractor / Funded Organisations
Pest and Weed Control              
Pest Control              
Plants and Animals              
Wildlife Management              
Fields of Study
Wildlife Management