Variation in egg organic content and its relationship with egg size in the starfish Solaster stimpsoni

Mean size (volume) of the eggs of the starfish Solaster stirnpsonl was 0.406 mm3 (n = 658); this did not differ among 4 locations in Barkley Sound, on the west coast of Vancouver Island, Canada.However, there were significant differences in mean egg size among females at each location.The range of egg sizes among s i b h g s w i h n a single spawn was 28 and 39 % of the mean size for 2 females (n = 100 for each sample).Egg organic content (measured for individual eggs) was also variable.Mean content was 113.9 pg organic carbon egg-'.There were significant differences in egg organic content among locations and among females within a population.The range of sibling variation was 43 and 48% of the mean content.However, egg size was not a reliable predictor of egg content.Even the extreme egg sizes failed to yield significantly different predictions of egg content.Therefore the assumption that egg size is a reliable indicator of parental investment per offspring is not warranted in intraspecific life history studes.