THE POPULATION-DYNAMICS OF THE PARASITIC COPEPODE LERNAEOCERA-LUSCI (BASSETT-SMITH, 1896) ON ITS DEFINITIVE HOST

The mesoparasitic copepod Lernaeocera lusci (Bassett-Smith, 1896) was recovered from first-year bib (Trisopterus luscus L.) in the Voordelta (Southern Eight of the North Sea) from May until December 1989. Analy sis of the seasonal abundance and of the population structure showed t hat transmission of infective stages to bib mainly occurred from June to September. From September to December the overall prevalence fluctu ated around 70%. Maximum parasite population size (47/10(4)m(2)) and t he highest total egg number were recorded in September and October, re spectively. It was found that total parasite mortality was significant ly influenced by mortality of hosts carrying parasites. Natural mortal ity probably contributed a small percentage to total parasite mortalit y. Calculation of the temporal mean-variance regression equation revea led that the parasites were aggregated within the definitive host popu lation.