Growth of the sponge Pseudosuberites (aff.) andrewsi in a closed system

Explants of the Indo-Pacific sponge Pseudosuberites aff. andrewsi were fed with the microalgae Chlorella sorokiniana and Rhodomonas sp. It was microsc opically observed that these algae were ingested and digested by the sponge cells, suggesting that they were consumed by the sponges. The algae were f urther used for two growth experiments with five explants of P. aff. andrew si and four explants of P. andrewsi. Growth was measured as the increase in projected body area. The explants showed considerable growth (up to 730% i n 54 days for P. aff. andrewsi and up to 680% in 22 days for P. andrewsi), which is much higher than previously reported growth rates for sponges. Gro wth started after a stationary phase of 5-20 days in which the projected bo dy area did not increase. The growth of P, aff andrewsi appeared to be line ar and was inhibited at the end of the experiment. Two explants of P, andre wsi showed exponential growth instead of linear growth. Hence, no general s tatements about the growth kinetics of these sponges can be made at this ti me. However, the high growth rates found in this study suggest a promising future for cultivation of sponges in closed systems. (C) 1999 Elsevier Scie nce B.V. All rights reserved.