Nearshore contagion and sampling of freshwater larval fish

The existence of larval fish contagion and its approximate magnitudein four different biotopes: at the shore of a river, surfaceand at fixed depth at an exposed coast of a large lake, andin a shallow, sheltered bay, was investigated, using passiveand active sampling. Non-random distributions were the rule;patchiness differed according to species, size, abundance anddiurnal movement, and was inversely related to distance fromshore. Characterization of contagion was hindered by samplingequipment and techniques, which were found wanting.