COWART, J.D.**; PAWLIK, J.R; Univ. of North Carolina Wilmington; Univ. of North Carolina Wilmington: Is there a trade-off between reproduction and growth form for two closely related Florida reef sponges?

Sponges are prominent members of coral reef communities, where they often rival scleractinian and alcyonarian corals in both diversity and abundance. Nevertheless, little is know about the reproductive biology of coral reef sponges. The purpose of this study is to determine if a trade-off exists between reproduction and growth form for two prominent and closely related Florida reef sponges, Callyspongia vaginalis and C. armigera. Callyspongia vaginalis commonly grows as clusters of erect tubes and will not survive dislodgement, while C. armigera grows as a branching, often interconnected rope-form and easily reattaches to the substratum after dislodgement. Both species brood larvae in broodchambers and recent evidence suggest that larvae are released year round. Larval traps were placed over a single tube of 10 C. vaginalis and over 10 C. armigera for 5 days in June and August 2005. The total number of larvae released was counted daily. At the end of each trial the sponges were collected and volume recorded. Results showed that 70% of C. vaginalis and 20% of C. armigera released larvae in June and 90% of C. vaginalis and 50% of C. armigera released larvae in August. The total number of larvae released over the 5-day period ranged from 2-153 for C. vaginalis and 22-53 for C. armigera in June and 2-191 for C. vaginalis and 1-20 for C. armigera in August. There was no correlation between the size of the sponge and the number of larvae released. These data support the hypothesis that rope-form sponges are morphologically adapted to exploit asexual reproduction by fragmentation as their major propagative process and resource allocation to sexual reproduction is consequently reduced relative to vase-form sponges.