Diel and depth variations in the sex-specific abundance, size composition, and food habits of queenfish, Seriphus politus ( Sciaenidae).

Abstract

Queenfish were taken from 5-27m bottom depths off the coast of N San Diego County, California. Both sexes made diel, onshore and offshore migrations, except for immature fish. Both immatures and adults occurred in epibenthic, resting schools in shallow areas (approx 10m or less depth, within approx 1.5km of shore) during the day. At night, adult fish dispersed (to >3.5km) offshore. On average, a greater fraction of the adult males emigrated farther offshore at night than adult females. Immature fish remained inshore of 16m bottom depths (within approx 2.5km of shore) at night, with the majority staying inshore of approx 10m depth. Larger fish occurred farther offshore at night. Stomach contents data confirmed the primarily nocturnal feeding habits of both immature and adult queenfish. Immatures fed primarily on meroplankton and other nearshore prey; adults captured offshore had also eaten some nearshore prey. Food habits explain much, but not all of the diel migratory pattern. Immature queenfish may also remain nearshore at night because migration is not worthwile energetically and because of greater risk of predation offshore. Adults perhaps also migrate offshore at dusk to spawn. -from Author Show more