Influences of brood-dependent behavioral variation on blue crab (Callinectes sapidus) larval transport in a wind-driven estuarine plume

Abstract

Blue crabs (Callinectes sapidus) support valuable fisheries in the US mid-Atlantic Bight (MAB), and their unpredictable and variable recruitment suggests that a better understanding of larval development and dispersal is needed. Blue crab larval dispersal involves export to the continental shelf followed by re-entry of estuaries. Transport is facilitated by wind and buoyancy-driven surface currents, and zoeae generally maintain a near-surface distribution. Though several studies have investigated C. sapidus larval dispersal, none have evaluated the effects of behavioral variability on transport. This study simulates first-stage larvae using documented behavioral variation within an idealized wind-driven estuarine plume in order to investigate the roles of swimming behavior, stratified current systems, and turbulent mixing on transport. Model results showed that larval transport was predominately influenced by wind speed, but transport was significantly affected by behavioral characteristics. Faster swimming larvae were more able to maintain a near-surface position and had more control over their vertical position despite vertical diffusivity, and in all model scenarios, larvae travelled farther and had different vertical distributions than passive particles. Modeled net transport distance of simulated broods differed by a factor of 1.8, with a maximum 4.7 fold difference between any individual larvae, and in all scenarios behaving larvae showed further net transport and a shallower vertical distribution than passive particles. These results indicate that blue crab larval swimming ability and variability in behavioral traits may be an important factor in C. sapidus larval dispersal.