Planktonic availability, molt stage and settlement of blue crab postlarvae

Abstract

The authors quantified spatio-temporal variation in molt stage (developmental state) of blue crab Callinectes sapidus megalopae (postlarvae), and the relationship between planktonic availability, molt stage and settlement of megalopae during peak settlement in Chesapeake Bay, USA Settlement was significantly correlated with the planktonic availabilityof megalopae. Developmental state of megalopae also appeared influential in settlement because bluse crab megalopae displayed quantifiable changes in molt stage; molt stage of megalopae varied on a temporal scale of days to 1 mo or more, and a spatial scale of kilometers, apparently reflecting the physiological progression through the molt cycle by megalopae pulsing through settlement habitats; and molt stage of megalopae advanced in collections from the plankton, on artifical settlement habitats, and in the benthos, indicating the approach to settlement, metamorphosis and a benthic existence.