Meeting Abstract

12.1  Tuesday, Jan. 4  Timing, Terrain, and Thermoclines: Explorations of Swimming and Sheltering Behavior in Larval and Postlarval Lobsters JACOBS, M.W.*; SHUTTARI, N.; CHRISTMAS, A.F.; GALLAGER, S.; DEPPERMAN, J.; ATEMA, J.; McDaniel College; Boston University; Western Washington University; Woods Hole Oceanographic Institution; University of Oldeburg, Germany; Boston University mjacobs@mcdaniel.edu

The lobster Homarus americanus releases swimming larvae that feed and grow through three molt stages in the plankton before metamorphosing into a postlarval settlement stage. During the settlement stage, postlarvae gradually transition from planktonic to benthic life, and from a roving, exploratory lifestyle to a very cryptic benthic one. This behavioral transition may be affected by a wide variety of environmental and social factors. We present an overview of experiments with larval and postlarval lobsters that have examined (1) variation in swimming behavior of larvae and postlarvae in response to physical barriers such as a thermocline or sharp change in light level; (2) variation in settlement behavior of postlarvae as a function of age from hatching, age from metamorphosis, population, maternal parentage, population density, and settlement terrain. Our results suggest that metamorphosis and settlement of lobsters are complex and flexible processes, strongly influenced by environmental factors such as shelter availability and food level that would affect the survival of juveniles, and relatively unaffected by larval experience, the length of the larval period prior to metamorphosis, or the presence of a thermocline. Settlement appears to involve two separate transitions: a transition from planktonic to benthic living, and a transition from exploratory to cryptic behaviors. We explore the relative timing of these two important transitions during settlement, and present preliminary evidence that settlement timing may vary as a function of population of origin.