Fall and spring somatic energy content for Alaskan Pacific herring ( Clupea pallasi Valenciennes 1847) relative to age, size and sex

• Published in: Journal of experimental marine biology and ecology 1998-05, Vol.223 (1), p.133-142
• Main Authors: Paul, A.J, Paul, J.M, Brown, E.D
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Clupea; Clupea pallasi; Energetics; Fundamental and applied biological sciences. Psychology; Pacific herring; Soma; Vertebrata
• ISSN: 0022-0981; 1879-1697
• DOI: 10.1016/S0022-0981(97)00157-3

During the fall of 1995 and spring of 1996, the whole body energy content (WBEC) of Pacific herring ( Clupea pallasi Valenciennes 1847) from Prince William Sound, Alaska, was examined. Somatic energy (kJ·g −1 wet wt.) exhibited a wide range of values relative to fish length. In the fall young of the year (YOY) recruits had an average of 5.7 kJ·g −1 wet wt. for whole body samples vs. 8.0 for age 1 and 9.4–10.2 kJ·g −1 for fish of ages 2 to 7. The following spring the 1995 year class which had just survived their first winter averaged 4.4 kJ·g −1 wet wt. for somatic samples, and age 1 fish had similar values, while herring ages 2 to 7 had WBEC>5 kJ·g −1. The difference in somatic energy content between adult male and female fish captured in fall and again in the spring just prior to spawning, was about 4 kJ·g −1 wet wt., or about a 40% change. The difference in mean values for somatic energy content for YOY herring was only about 1.4 kJ·g −1 suggesting either the recruits ate more food during the winter than the adults, had lower energetic needs, or only those with higher than average energy stores survived the winter. The fall measures of WBEC showed the YOY and age 1 fish stored markedly less energy to over-winter than older herring. Thus, energetically the recruiting year class, and those entering their second winter, are the most at risk of over-winter mortality.