Publication Abstract

Discriminating offshore sites using fish disease profiles and context for the use of disease data in marine environmental monitoring

*G.D.Stentiford, *J.P. Bignell, B.P. Lyons* and *S.W. Feist

Clinical fish disease and liver pathology are utilised as high-level indicators of ecosystem health in marine environmental monitoring programmes. Internationally agreed protocols for their measurement have allowed for comparison of datasets that transcend international marine boundaries and have promoted the collection of quality assured data from national marine monitoring programmes from several countries bordering the north-east Atlantic and associated seas. In this study, a range of well-described external diseases and liver pathologies (including those associated with carcinogensis) were recorded over the period 2002 to 2006 from UK Clean Seas Environmental Monitoring Programme (CSEMP) offshore sites in the Irish and North Seas and in the English Channel, United Kingdom. Quality assurance in diagnosis was provided by application of protocols developed by the International Council for the Exploration of the Sea (ICES) and under the European Biological Effects Quality Assurance in Monitoring (BEQUALM) programme. Multivariate analysis of disease data from these sites revealed a relatively stable disease profile at most sites over the years of study. In particular, those sites with the highest levels of external diseases and liver pathology (including benign and malignant liver tumours) consistently grouped together within a given year, and distinctly from those sites that displayed a lower prevalence of disease. Analysis of between-year multiple dimensional scaling plots for these sites demonstrated the repetitive nature of these patterns, suggesting that disease profiles within flatfish fish populations are relatively consistent between years, even at open ocean sites. An overall assessment of prevalence for the different diseases allowed for a simple grading system to be developed that assigned a relative ‘harm’ score for populations existing at a particular geographic site. Grading of the relative harm score into site types (A, B, C) may provide an assessment tool for managers to identify sites or regions of concern and to cross-correlate disease with potential causal factors associated with those locations. The use of disease data in marine environment status monitoring is discussed.