ECHINODERM EGG AND LARVAL QUALITY AS A FUNCTION OF ADULT NUTRITIONAL STATE

Differences in egg and larval quality for some sea urchins and seastar s were investigated in the field acid in the laboratory. In the field, sea urchins and seastars found at sites with an abundant supply of fo od were larger, and they produced large numbers of large, high quality eggs. For some female seastars, nutritional history determined the re sponse to variation in food supply in the laboratory. While an increas e in food ration did not affect the size of eggs produced by females f rom the favorable site, an increase in food ration led to an increase in egg size for those from the less favorable site. For all the echino derms examined, egg numbers decreased when conditions became unfavorab le. Larvae from females living in favorable environments grew and deve loped faster, and larval survival was high. A large percentage of sea urchin larvae from females living in favorable environments metamorpho sed compared to those living in less favorable environments. Juvenile size did not vary as a function of past nutritional state in sea urchi ns but it did in seastars. Large numbers of high quality juveniles wer e produced by seastars from the favorable site. The differences in egg and larval quality observed in field studies might be due to differen ces in the abundance of preferred algae (food for some sea urchins) an d molluscan species (food for some seastars) at the different sites. I n laboratory studies, the responses to food availability were also inf luenced by the nutritional and gametogenic states of the females at th e time of collection and by the duration of the experiments.