DIGESTION OF COPEPOD EGGS BY LARVAL TURBOT SCOPHTHALMUS-MAXIMUS AND EGG VIABILITY FOLLOWING GUT PASSAGE

Between 20.5 and 93.6% of the subitaneous eggs of 6 species of egg-carrying copepods passed undigested through the digestive tracts of larval and early post-larval turbot Scophthalmus maximus. Viability of the eggs of Eurytemora affinis, E. velox and Euterpina acutifrons remained high on egestion (67.0 to 91.7%), Pseudocalanus elongatus and Oncaea venusta eggs had low viability (1.1 to 1.5%), while all Corycaeus anglicus eggs were rendered inviable. The indigestibility of the eggs denies the turbot larvae a potentially valuable food resource, while retention of high egg viability in certain species reduces the effect of predation.