§ Mr. Matthew TaylorTo ask the Minister of Agriculture, Fisheries and Food what percentage of(a) dab, (b) flounder, (c) cod, (d) herring and (e) plaice caught in water around the United Kingdom showed evidence of disease for each of the ad hoc surveys conducted since 1980 by the Ministry of Agriculture, Fisheries and Food, together with the Department of Agriculture and Fisheries for Scotland.
§ Mr. CurrySince 1980, the Department's surveys for fish diseases in water around the United Kingdom have shown wide differences in prevalence between fish species. For dab and flounder, external diseases are recorded at higher prevalence rates than in cod, herring or any other species.
The prevalence rates of disease vary not only between species but in relation to abundance, size, sex, spawning state and food availability. For dab and flounder, up to 10 567W per cent. prevalence would be expected in some areas, and then fluctuations would be expected according to the season. For cod, diseases are noted only when the migrations occur inshore during the autumn. At this time approximately 10 per cent. has been recorded, but this figure varies between years. Diseases in herring are rare, that is, less than 1 per cent. in all our surveys.
Monitoring prevalence of disease in marine fish is only useful when it is made over an extended time period, and when all biological and physical parameters have been taken into account. We know that all current diseases in the above species have been documented since the turn of the century.