EFFECT OF SALINITY ON DEVELOPMENT OF LARVAE OF HETEROSACCUS-LUNATUS (CIRRIPEDIA, RHIZOCEPHALA)

Heterosaccus lunatus is a rhizocephalan barnacle which parasitizes the crab Charybdis callianossa in Moreton Bay, Queensland. Its free-swimm ing larvae are lecithotrophic and there are 4 naupliar stages before m etamorphosis to the cypris stage. Sexes can be distinguished during th is larval phase by size, the male larvae being larger at all stages. E xperiments determined the effect of differing salinities on larval dev elopment of H. lunatus. A development index (D.I.) was calculated for each salinity tested and larval development was arbitrarily deemed suc cessful if the D.I, was greater than 50%, i.e., > 50% of the nauplii b ecame cyprids. Successful larval development occurred over the salinit y range 24-40%.