Selective feeding of spot, Leiostomus xanthurus, and Atlantic croaker, Micropogonias undulatus, larvae in the northern Gulf of Mexico

Abstract

When examined in relatlon to their availability in the plankton, the organisms eaten by larval spot Leiostomus xanthurus and Atlantic croaker Micropogonias undulatus collected in the northern Gulf of Mexico indicated that these larvae feed selectively.Two electivity indices indicated that both small (1.00 to 5.00 mm) and large (5.01 to 10.00 mm) spot larvae selected copepodid and adult copepods (Stages C1 to CVI), pteropods, and pelecypods.Small croaker larvae also selected copepodid and adult copepods, as did large croaker larvae.Small and large larvae of both species selected Oncaea sp. from among the copepods, while one or more length categories of either species selected Oithona spp., Paracalanus spp., Corycaeus spp., and Acartia tonsa.Select~on appeared to be related not only to the width, but also to the sw~mming behavior and color of food organisms.