Settlement of Spiny Lobster, Panulirus Argus (Latreille, 1804), in Florida: Pattern Without Predictability?

Abstract

We used plankton nets, floating postlarval collectors, and arrays of benthic settling devices, along with diver surveys of juvenile lobster abundance and nursery habitat structure, to estimate the spatial pattern of settlement, abundance of settlers, and characteristics of postsettlement juvenile Panulirus argus populations in Florida Bay, the primary nursery for spiny lobsters in Florida. Within a 200 km 2 region of Florida Bay, settlement was patchy and locally unpredictable, although settlement occurred at most sites each lunar phase. However, the number of postlarvac entering inlets to the bay was significantly correlated with regional settlement, and areas with abundant red macroalgae (settlement substrate) and numerous sponges (benthic juvenile shelter) were the most productive sites, even though settlement within them varied widely during lunar influxes. Floating collector catches accurately estimated the number of postlarvae in the water column at inlets, but results from collectors deployed in the bay did not correlate with the number of postlarvae settling on benthic collectors nearby. Estimates of postsettlement mortality in the field yield a natural mortality of about 97% in the year following settlement.