Factors regulating postlarval settlement and juvenile microhabitat use by spiny lobsters Panulirus argus

Clumps of highly-branched red algae Laurencia spp.serve as important settling habitat for postlarval spiny lobsters Panulvus argus and as residence for early benthic-stage juveniles.G ~v e n choice between the 2 most abundant macrophytes in Florida Bay, Laurenna spp.and the seagrass Thalassia testudinum, postlarval and juvenile lobsters chose Laurencia spp.Postlarvae apparently use intricate algal architecture as a cue for settlement, whereas juveniles use both architecture and food abundance in selecting habitat.In tethering experiments, predation on juve~ule lobsters was very high on open sand, much reduced In algal clumps and seagrass, and lowest in dense algal meadows.Predation rates were s~milar day and night both on open sand and In vegetabon.Most lobsters vacated algal clumps located within continuous algal meadows overnight, at a rate significahtly higher than that from isolated algal clumps.We suggest that algal clump d ~s t n b u b o n , postlarval settling behavior, and juvenile interpatch movement and mortality contribute to the highly dispersed distnbution and locally sparse abundances of early benthic juveniles.