R/Cr-4 A

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Description:

Objectives: We seek to identify patterns in the timing and abundance of influx of shelf-spawned ichthyoplankton into Chesapeake and Delaware Bay, discern whether there are different physical mechanisms that influence ingress between these estuaries, and evaluate our results with respect to factors causing recruitment variability. We propose to 1) identify and compare the timing of larval fish ingress into Chesapeake and Delaware Bays for a suite of species, and 2) identify and compare specific cross-shelf transport mechanisms that influence the ingress of Atlantic croaker and American eel. Methodology: We propose to use a combination of fixed-site sampling, research cruises, and observing system data to identify ingress of young fishes into estuaries. Year-round weekly sampling at fixed locations, supplemented by high-frequency sampling during targeted periods, will be used to determine the ingress of larval fishes into each estuary. High-frequency sampling at the fixed locations will be combined with research cruises to allow us to develop a clearer picture of processes influencing larval influx into each estuary for selected species(menhaden, croaker and eel). Results of physical measurements and larval sampling at fixed locations and on survey cruises will be combined with observing system data and numerical models to identify patterns and cross-shelf transport processes that influence larval ingress. Rationale: Coastal-spawning fishes are important components of commercial and recreational fisheries in Chesapeake and Delaware Bays, yet mechanisms that control their influx and recruitment into these systems are poorly understood. This research will increase our understanding of physical processes that influence larval transport from coastal spawning areas to estuarine nurseries. The proposed regional program will enhance fisheries management planning and the design of regional monitoring programs by providing advice on sampling required to adequately describe larval influx. Results will complement other ongoing or planned Atlantic coast sampling programs measuring larval ingress into estuarine nurseries.