Methodology of fish disease surveys: Report of an ICES Sea-Going Workshop held on U/F "Argos" 16-23 April 1988

Through a combination of discussions, formal presentations and practical trials, the ICES workshop held on board U/F Argos from 16-23 April 1988 considered the methodology of fish disease• surveys. Particular emphasis was placed on assessing and updating the proposals of the 1984 workshop in the light of four years of practical application. Substantial differences still exist regarding the pathological conditions that are monitored and regarding diagnostic interpretations, particularly when diseases occur at low levels. The major source of sampling variability still existing was identified as the difficulty and reliability in detecting light cases of disease (particularly lymphocystis). For ICES reporting purposes it is recommended that only a restricted number of disease conditions be included and that, to improve reliability of

data for international comparison, results below clearly defined levels of disease severity should be excluded.