Influence of explant procedures and environmental factors on culture success of three sponges

Lack of evidence that sponge aquaculture can produce sustainable supply of target metabolite for industrial or pharmaceutical use is constraining commercial development. Experiments to determine aquaculture feasibility examined the influence of environmental factors and explant characteristics on the growth and survivorship of three morphologically distinct sponge species — Psammocinia hawere, a massive cup-shape fibrous sponge, Raspailia agminata, a thickly encrusting siliceous sponge and Raspailia topsenti, a branching digitate siliceous sponge. A variety of expiant types were cultured at different exposures, depths and seasons. P. hawere expiants transplanted to deeper water in winter demonstrated highest growth and survivorship. This was attributed to a relatively lower intensity of UV radiation and cooler water temperatures which promoted fast pinacoderm healing. Growth and survivorship increased with increasing explant size and with proportion of intact pinacoderm. R. agminata explants demonstrated the highest growth rates, perhaps a function of the encrusting and flexible morphology. Highest growth and survivorship were obtained in sheltered locations. Within each species, ratio of body size to wound size and overall size of the wounds inflicted, would greatly influence survival, but with respect to temperate rocky reef sponges, this study suggests that encrusting and amorphous sponges have the greatest potential for success in aquaculture.