LARVAL BEHAVIOR, HYDRODYNAMIC TRANSPORT, AND POTENTIAL OFFSHORE-TO-INSHORE RECRUITMENT IN THE AMERICAN LOBSTER HOMARUS-AMERICANUS

Theoretical and field patterns of offshore larval dispersal were explored for the American lobster Homarus americanus on the southern New England (USA) continental shelf. Our field collections along an offshore-inshore transect revealed a gradient of larval stages with a greater proportion of earlier stage larvae in the vicinity of offshore canyons, and more mature stage III and IV larvae dominating larval distributions closer to coastal habitats. An empirical trajectory model integrating larval behavior and hydrodynamic properties was then constructed to evaluate potential dispersal mechanisms. Model simulations suggested that passive drift via surface currents and wind-induced transport were insufficient conditions for offshore recruitment subsidies to coastal populations. In contrast, directional swimming of the fourth stage larvae resulted in successful dispersal to the coast within the duration of the planktonic phase of H. americanus.