Temporal and spatial co-occurrence in spawning and larval release of Cliona viridis (Porifera : Hadromerida)

This is the first report of egg release by the oviparous excavating sponge Cliona viridis. Adult specimens of excavating (alpha) and massive (beta) sp onge forms for the presence of oocytes were monitored from 11 May to 12 Jul y 2000, in a shallow-rocky coast of the north-west Mediterranean. The immed iate environment around the sponge was sampled for the presence of eggs. Sp awning occurred synchronously in the study area at temperatures above 19 de greesC. Oocytes were released in clusters enclosed in adhesive maternal tis sue. They contained symbiotic zooxanthellae. Free, adhesive egg-masses drif ted in the water or adhered to erect algae in the vicinity of the sponge. M orula stages and larval release are described.