Macroalgae (Rhodophyta: Laurencia spp.) as habitat for young juvenile spiny lobsters, Panulirus argus

Field surveys were conducted in the middle Florida Keys to better document habitat used by newly settled juvenile spiny lobsters, Panulirus argus. Early benthic stages were most numerous in locations where they resided in or beneath macroalgal clumps of red algae Laurencia spp. Macroalgae provide refuge and support an abundant, diverse fauna preyed upon by young lobsters. Postlarval settlement occurred at monthly intervals, indicating continuous use of the algal microhabitat by successive settlement classes. Patterns of resource use were well defined ontogenetically. From settlement (6 mm carapace length) through approximately 17 mm CL, young lobsters remained within algal clumps, thereafter moving to the substrate to take residence in various den structures. The transition from algal to den dwelling was accompanied by a shift from solitary to aggregate habitation. However, this apparent change in sociality was not rigidly fixed ontogenetically but depended in part on the local distribution of shelter and food.