Nearshore contagion and sampling of freshwater larval fish

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