Seasonal changes in carotenoid and lipid storage by threespine stickleback, Gasterosteus aculeatus

Total body astaxanthin and lipid concentrations in threespine stickleback (Gasterosteus aculeatus) collected from fall through the start of the breeding season were correlated; concentrations of each increased between fall and spring and decrease during the pre-breeding season. Individual tissues (skin, muscle, viscera, carcass, and gonads) showed a decrease between the spring and pre-breeding seasons; beta-carotene also decreased in all tissues except the skin, where there was an increase. Unlike previous studies, beta-carotene, but not astaxanthin, was deposited in the skin prior to nesting, suggesting that that beta-carotene is the carotenoid responsible for creating the nuptial signal in this wild population.