RAPID GROWTH, HIGH FEEDING RATES, AND EARLY PISCIVORY IN YOUNG-OF-THE-YEAR BLUEFISH (POMATOMUS SALTATRIX)

The bluefish (Pomatomus saltatrix) is an offshore-spawning estuarine-d ependent fish that is abundant along the east coast of North America. Young-of-the-year bluefish undergo a habitat shift from offshore water s to inshore nursery areas at about 40-70 mm total length which coinci des with an increased growth rate and a diet shift from planktivory to piscivory. Here, we measure growth of young-of-the-year bluefish on d ifferent diets and estimate consumption rates both in the field and in the laboratory. Growth on a fish diet is significantly higher than th at on a zooplanktivorous diet. Bluefish have among the highest evacuat ion (5-7 h), consumption (20-30% body weight/d), and specific growth r ates (1-2 mm/d) reported for temperate fishes and are similar to those for pelagic tropical species. These results suggest that bluefish may exhibit a tropical feeding physiology in temperate estuarine nurserie s as a way to achieve rapid growth rates.