PATHOGENICITY OF LERNAEOCERA-LUSCI AND L-BRANCHIALIS IN BIB AND WHITING IN THE NORTH-SEA

The pathogenicity of the crustacean parasites Lernaeocera lusci and L. branchialis towards their definitive host species (bib and whiting, r espectively) was studied in the Dutch and Belgian coastal area. Negati ve correlations between parasite intensity and haematocrit value were found for both parasite species. L. branchialis was the more pathogeni c species: the parasite-induced reductions in haematocrit value were m ost significant for this species. It is assumed that parasite-induced host mortality can act as a regulatory force at high parasite densitie s in natural populations.