The circulation over the continental shelf off the southern Middle Atlantic Bight (MAB) and northern South Atlantic Bight (SAB) is examined for the fall and winter periods. Observational data are compared with results from a three‐dimensional numerical model to identify the dominant processes on the shelf. By considering wind‐forcing, tides, and a specified upstream inflow (into the MAB), the observed and modelled flow fields are in close agreement in the mid‐ and inner shelf regions. The resulting larval drift indicates a seasonal dependence of transport pathways from spawning grounds to estuarine nursery areas for menhaden larvae and other offshore‐spawning estuarine‐dependent fish. Specifically, the physical oceanography of the MAB and SAB during the fall and winter months suggests a north‐to‐south shift in spawning areas providing recruits to the Carolina estuaries, in agreement with the observed migration of the spawning populations.

A three‐dimensional circulation model was used in conjunction with larval fish vertical behaviour models to study the interaction between larval vertical distribution, advection and the outcome of larval transport along the central portion of the east coast of the United States. The circulation model was forced by tides, a northern boundary inflow, and winds. Vertical behaviour models were developed for Atlantic menhaden (Brevoortia tyrannus) and spot (Leiostomus xanthurus). The purpose of this modelling effort was to investigate the transport pathways of Atlantic menhaden and spot larvae from offshore spawning grounds to estuarine nursery habitats. The coupled circulation and behavioural model demonstrated the importance of along‐shelf transport in what is generally thought to be a ‘cross‐shelf’ problem. Cross‐shelf transport was associated with bathymetric features, such as shoals. Both physical (e.g. wind) and biological (e.g. changes in larval behaviour) events were responsible for many of the observed patterns in larval transport. Overall, larval transport was determined by circulation but was modified by larval vertical distributions.

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.

We examined patterns of abundance, age and spawning date distributions of Atlantic menhaden Brevoortia tyrannus larvae immigrating during two seasons through three North Carolina inlets—Oregon, Ocracoke and Beaufort—to elucidate their spawning and transport dynamics. These patterns were examined in conjunction with corresponding predictions from a three‐dimensional, wind‐and tide‐driven hydrodynamic model. Larvae immigrating through different inlets showed consistent similarities as well as marked differences in temporal patterns of abundance, spawning dates and transport times. Intraseasonal patterns in abundance and spawning date distributions among inlets suggest that, in both study years, the spatio‐temporal dynamics of menhaden immigration were driven by large‐scale patterns along the Atlantic coast, rather than by localized variation in spawning activity. Interannual differences in the temporal patterns of spawning dates and larval immigration indicate interannual differences in transport dynamics and/or the spatial‐temporal distribution of spawning. When the spawning locations predicted by the hydrodynamic model are interpreted in conjunction with advanced very high resolution radiometer sea‐surface temperature information, the results are consistent with the limited historical information available on spatio‐temporal distribution of Atlantic menhaden eggs and larvae. The transport model also predicted distributions of arrival times for immigrating larvae that were comparable in range and variability with observed patterns. Our use of data from immigrating larvae, coupled with a hydrodynamic transport model and sea‐surface temperatures, allowed us to uncover relationships between spatio‐temporal patterns of Atlantic menhaden spawning and transport dynamics that could not have been identified by either approach alone.

Present theory suggests that population regulation in marine fishes cannot be resolved until an understanding of the processes involved in shaping the overall distribution (the number of populations, geographical extent, mean abundance and temporal changes in abundance) is developed. Here, we present a step toward understanding Atlantic menhaden population patterns, by studying processes in the Middle and South Atlantic Bights, which shape those patterns. We use individual‐based and hydrodynamic models to reinterpret the ‘mechanics’ of the menhaden life history, and put forward several potentially testable hypotheses. The success of the menhaden reproductive strategy seems to depend on the seasonal changes in the mean flow field of the Middle and South Atlantic Bights, suggesting that their life history may have been strongly structured by the regional physics of the system. Because the annual menhaden migration is size‐based and spawning occurs throughout the population’s range, the size distribution of the adult population may influence the supply of larvae to particular estuaries along the coast. Recruitment of larvae into Delaware and Chesapeake Bays may be dependent on spawning to the north of the bays’ mouths, owing to coastline shape and orientation in the vicinity of the bays. Our results suggest that management of this resource might be improved by consideration of the spatial and temporal variability in both the biological and the physical system.