Effects of the duration of larval life on postlarval stages of the demosponge Sigmadocia caerulea

Variability in the duration of the free-swimming period of lecithotrophic larvae of the demosponge Sigmadocia caerulea (Hechtel, 1965) was assessed in the laboratory in the absence of metamorphic inducers and inhibitors. The free-swimming period in three clutches of larvae ranged from 8 to 70 h and the cumulative settlement curve was sigmoid, with settlement peaking between 20 and 28 h after release. There were significant differences among clutches in the time to reach 50% settlement. Within each clutch, small percentages of larvae (<25%) were short-lived (settled less than 12 h after release) or long-lived (settling more than 32 h after release). Juveniles originating from short-lived larvae survived better, grew faster and were more regular in shape than those originating from long-lived larvae.