Diet of age-0 tarpon Megalops atlanticus near their northern range limit in the western Atlantic Ocean

Abstract

The Atlantic tarpon Megalops atlanticus is a tropical-subtropical fish that occupies mangrove and salt marsh habitats during the first year of life. Diet during the first few months of life can have substantial effects on growth and survival of fishes. The purpose of our study was to examine the diet of age-0 tarpon in the North Inlet-Winyah Bay estuarine system, located near the northern extent of their distribution in the western Atlantic Ocean. We examined stomach contents to characterize tarpon diet and relate tarpon feeding to water temperature. The most important prey items based on the frequency of occurrence and proportion by weight indices were small fishes and crustaceans, whereas copepods were the most important prey based on the proportion by number index. Small age-0 tarpon (\(\le\) 100 mm) consumed small crustaceans (copepods) while large age-0 tarpon (> 100 mm) consumed larger crustaceans (shrimp) and age-0 tarpon of all sizes consumed fish. Most tarpon with empty stomachs were collected at temperatures < 25 °C, whereas most tarpon with prey in their stomach were collected at temperatures > 25 °C. The proportion of tarpon having at least one prey item in their stomach contents was greatest around 28 °C and declined at lower and higher water temperatures. Salt marsh habitats in the North Inlet-Winyah Bay estuarine system provide suitable food resources for age-0 tarpon. As water temperatures increase and tropical species, such as tarpon, expand their range, these coastal nursery habitats may become more important for tarpon growth and recruitment to the spawning stock.