Changes in proximate composition and somatic energy content for Pacific sand lance (Ammodytes hexapterus) from Kachemak Bay, Alaska relative to maturity and season

Mean dry-weight energy values of adult Pacific sand lance (Ammodytes hexapt erus) peaked in spring and early summer (20.91 kJg(-1) for males, 21.08 kJg (-1) for females), then declined by about 25% during late summer and fall ( 15.91 kJg(-1) for males, 15.74 kTg(-1) for females). Late summer declines i n energy density paralleled gonadal development. Gender differences in ener gy density (males < females) were only apparent from August to October. Adu lt sand lance spawn in October, entering the winter with close to their min imum whole body energy content. Juvenile sand lance exhibited a relatively constant protein to lipid ratio until they reached 80 mm fork length. There after, relative proportions of protein remained constant while lipid propor tions increased significantly. Dry weight energy densities of juveniles inc reased from a minimum 16.67 kJg(-1) to a maximum of 19.68 kJg(-1), and (per g) are higher than adults in late summer. The seasonal food value of adult sand lance to predators varies markedly, but maximum energetic value coinc ides with important feeding periods for marine mammals, fish, and seabirds. Published by Elsevier Science B.V.