Larval release and supply predict temporal variation in settlement of a colonial ascidian

Abstract

Temporal variation in the number of larvae released, number of planktonic larvae, and settlement density was examined for Didemnum candidum in Pearl Harbor, Hawaii. Larval release, planktonic larvae and settlement occurred only during the daytime, with a strong early morning and weaker afternoon peak in abundance. Diel variation in larval release and abundance of planktonic larvae accounted for a large part of the variation in settlement. The close temporal link between larval release and settlement indicates that planktonic larval availability, as controlled by larval release, is an important determinant of settlement intensity. -from Author