Sex-specific seasonal variation in the carotenoid content of sea urchin gonads

Abstract

This study documents the effect of sex on gonad carotenoid content during the annual reproductive cycle of Strongylocentrotus droebachiensis from northern Norway. Male and female S. droebachiensis exhibited distinctly different patterns of carotenoid variation, with seasonal carotenoid depletion and replenishment in females and carotenoid retention in males. Females lost approximately 71.1% of their echinenone during spawning, and compensated for the loss by active deposition during gonad regrowth. Female carotenoid levels (100 to 275 μg g–1 dry mass), although lower and less variable than male carotenoid levels, were consistently higher than predicted by estimates based on a constant post-spawning carotenoid content. Males did not lose carotenoids during spawning, and the concentration of carotenoids in male gonads varied from >600 to <200 μg g–1 dry mass, apparently as a passive result of increasing gonad size. The results suggest that carotenoid supplements in urchin diets would be largely wasted in gonad enhancement cultivation of male S. droebachiensis, and emphasize the importance of controlling future feeding trials for the confounding effect of sex on carotenoid deposition.