Fine-scale distribution of nearshore, suprabenthic fish larvae

Abstract

A large-volume pump was used to sample larval fish and zooplankton at approx heights of 30, 60, and 100 cm above the bottom over the 7 m isobath during a 12 h period. Zooplankton biomass increased exponentially with proximity to the bottom, as did Gobiidae Type A larvae (a complex consisting of Ilypnus gilberti, Quietula ycaudata , and Acanthogobius flavimanus ) during the day. At night, the gobiids became more or less evenly distributed in the lower meter. Larval queenfish Seriphus politus were taken in high numbers in daytime nearest the bottom, but in very low numbers in the 2 higher strata. At night, S. pokitus was more abundant at all depths, but still 3 times more abundant near the bottom than at higher levels. During the day, but not at night, there was an offshore component to near-bottom currents. A progressive vector analysis of current measurements made within the bottom meter indicated length scales of 1 to 2 km for the apparent patches.