Impact of the Distribution of Atlantic Menhaden Spawning Grounds on Nursery Recruitment Patterns in the Mid-Atlantic Bight

Population regulation in marine fishes cannot be understood without insights into processes that determine the spatial and temporal distribution of larvae. In marine fish that depend on estuaries for nursery habitats, a key process is the transport of larvae from spawning grounds to nurseries along the coast. Here we examine the impact of the spawning ground distribution on recruitment patterns in Atlantic menhaden (Brevoortia tyrannus) along the coast in the Middle Atlantic Bight (MAB). For this purpose we used results from a 3-D hydrodynamic model of the MAB (ESPreSSO) coupled offline to a particle-tracking model (LTRANS). Results from this first step were interpreted in light of known biological constraints affecting larval survival. Subsequently, recruitment to various potential nursery sites along the coast was assessed. We ran simulations lasting about 3 months, for a period covering spawning from the fall of 2006 to the spring of 2007. Results show (1) that recruitment patterns depend strongly on the mean southward flow prevalent in the MAB; (2) that accounting for tidal flow may be important in resolving recruitment; (3) that contrary to initial assumptions, winter spawning south of Chesapeake Bay may be key for recruitment in northern estuaries of the MAB.