Atlantic menhaden recruitment to a southern estuary: defining potential spawning regions

Abstract

Atlantic menhaden (Brevoortia tyrannus) is an estuarine‐dependent fish that spawns in coastal waters of the Middle and South Atlantic Bights. Circulation modelling studies of larval transport suggest that recruitment of larvae into the Albemarle‐Pamlico Estuarine System, North Carolina, is linked to dynamics on the shelf from New York to South Carolina. Field‐collected menhaden egg data (from MARMAP and SABRE) define a range of temperatures within which menhaden eggs have been found. In this study we refine the transport model‐predicted spawning grounds for the 1994–95 season by using satellite‐derived sea surface temperature data to highlight regions that are outside the observed spawning temperature range. We also use transport pathways leading from source locations to the estuarine system to characterize the temperature field experienced by particles/larvae during their spawning‐ground to inlet transit. The modelled nearshore location of source regions agrees well with MARMAP and SABRE egg data, and points to the importance of understanding biological and physical linkages between the Middle and South Atlantic Bights. The combination of modelled transport and synoptic temperature maps can provide useful guidance to future sampling efforts as well as help refine our understanding of menhaden ecology.