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Rainbow trout fin erosion - epidemiological analysis of prevalence, development, risk factors and effects on welfare - AW1204

Defra is committed to improving the welfare of farmed animals. A previous Defra funded fish welfare project (AW1203) has documented that rainbow trout farmed in the UK experience fin erosion - a progressive necrosis of fin tissue. Animal welfare groups have highlighted fin erosion as a fish welfare issue and a consequence of intensification. However, there is currently little objective information on the prevalence and the severity of the condition on UK farms, whether it is of concern to welfare, and the role of intensification. A large number of experimental studies have illustrated that various husbandry and environmental factors affect the severity of the fin erosion, indicating a complex multifactorial aetiology. Nevertheless, a field study of commercial rainbow trout farms in the USA demonstrated that just four key risk factors explained most of the between-farm variation in the severity of fin erosion. The main aim of this project is to identify the risk factors for fin erosion of rainbow trout held in UK production systems. This will be achieved by a field epidemiological approach assessing fin state on farms. A cross-sectional study in the first year will document the prevalence and severity of the condition across the industry, the variation between farms and give a preliminary indication of risk factors. This will be followed by a longitudinal (cohort) study to determine when fin erosion occurs during the production cycle, and identify key risk factors. Correlation of fin erosion to various other welfare indicators will allow an assessment of whether fin erosion does represent a major insult to trout welfare. The field-work will be supported by a comprehensive literature review. The identification of the key risk factors for fin erosion will enable strategies to reduce the prevalence and severity of fin erosion to be developed. The project results will also allow assessments of the extent of fin erosion within the UK rainbow trout industry and its importance to welfare. In addition, the results and methodology developed will facilitate the incorporation of fin erosion into farm assurance schemes. Thus the project will make a significant contribution to the improvement of the welfare of farmed rainbow trout in the UK.
Project Documents
• Final Report : Rainbow Trout fin Erosion - Epidemiological Analysis of Prevalence, Development, Risk Factors and Effects on Welfare   (774k)
Time-Scale and Cost
From: 2004

To: 2008

Cost: £298,721
Contractor / Funded Organisations
CEFAS, University - Stirling
Animal Welfare              
Plants and Animals              
Fields of Study
Animal Welfare