Overwinter Habitat Use, Feeding Habits and Energetics of Juvenile Bluefish in the Northern Florida Coastal Ocean

Recruitment success for juvenile fishes that take part in seasonal migrations may be dependent on the environmental conditions during the first winter of life. Juvenile bluefish (Pomatomus saltatrix) in the USA migrate from mid-Atlantic waters during the fall to overwinter in the coastal ocean of Florida and return again in the spring. Little is known regarding the recruitment dynamics and feeding ecology of juvenile bluefish at the southern edge of the species US range, particularly during winter. We examined the cohort structure, feeding habits, and lipid content of juvenile bluefish during late fall and winter in the northern Florida coastal ocean. We found that three juvenile bluefish cohorts migrated to the area at distinct temporal and spatial intervals. Abundance of juvenile bluefish was greatest during January and was dominated by the summer-spawned cohort. We first collected fall-spawned fish in January, and this was the only cohort collected by March, indicating the possibility of local spawning from a resident bluefish population. Stomach content analysis revealed that all three juvenile bluefish cohorts used the northern Florida coastal ocean to forage during the winter, and striped anchovy (Anchoa hepsetus) was the primary prey. Feeding intensity of juvenile bluefish was greatest in December and January, and their lipid content increased throughout the winter. Juvenile bluefish recruited to the coastal shelf waters of northern Florida, where the region provided this popular sportfish with distinct overwintering resources.