Patterns of Larval Atlantic Croaker Ingress into Chesapeake Bay, USA

We compared ingress patterns of Atlantic croaker Micropogonias undulatus larvae into Chesapeake Bay, USA, with published ingress patterns through barrier island inlets, the accepted model for larval fish ingress. This model asserts that larvae ingress on night flood tides at the flooddominated side of the inlet and at all depths. At the Chesapeake Bay mouth and in the adjacent coastal waters, we compared the distribution of abundance, size, age, and growth rates of croaker prior to ingress. In contrast to the barrier island inlet model, croaker larvae were more abundant at depth than closer to the surface regardless of location. However, the response to light was variable, where croaker larvae farther offshore showed no response to light, but croaker larvae in the bay mouth were more abundant at night. Croaker larvae followed an expected pattern of increasing age and length from offshore stations to the bay mouth station. Further, among nearshore coastal stations there was evidence of larger and older croaker larvae at the northern portion of the bay mouth than at middle or southern stations. Patterns in growth were similar at all locations, indicating the likelihood of a single source location or similar environments among transport pathways for croaker larvae. Ingress can occur across the entire mouth of Chesapeake Bay; however, net tidal inflow may result in age and size structuring, which allows more rapid movement into the northern flooddominated portions of the bay mouth.