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

Blue crabs (Callinectes sapidus) support valuable fisheries in the US mid-Atlantic Bight (MAB), and their unpre-dictable 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 par-ticles. These results indicate that blue crab larval swimming ability and variability in behavioral traits may be an important factor in C. sapidus larval dispersal.

Automated summary

Blue crabs (Callinectes sapidus) in the US mid-Atlantic Bight have unpredictable and variable recruitment, so understanding their larval development and dispersal is important. This study used a simulation model to investigate the effects of swimming behavior, current systems, and mixing on larval transport. Results showed that larval transport is mainly influenced by wind speed, but behavioral traits also play a significant role. Swimming larvae can maintain a near-surface position and have more control over their vertical distribution compared to passive particles. These findings highlight the importance of larval swimming ability and behavioral variability in blue crab larval dispersal.