Effect of activity on energy allocation in the northern abalone, Haliotis kamtschatkana (Jonas)

The effect of activity, in the form of increased respiratory energy expendi ture and secretion of mucus, on the summer and winter energy budgets of Hal iotis kamtschatkana was assessed. Abalone exhibited seasonal variations in field activity with 20% of all individuals observed crawling during June to October, compared with <5% during December to February. In the laboratory, abalone exhibited diurnal as well as seasonal variation in activity. The l aboratory activity budget showed that an average abalone spends 9.8 h day(- 1) quiescent, 12.0 h day(-1) alert, 0.7 h day(-1) feeding, and 1.5 h day(-1 ) crawling during the summer, and 15.8 h day(-1) quiescent, 5.5 h day(-1) a lert, 2.3 h day(-1) feeding, and 0.4 h day(-1) crawling during the winter. Videotapes of abalone made over 24-h periods revealed that abalone usually crawl at a rate of one shell length min(-1). Locomotion is not continuous; rather, abalone stop and then start again, on average twice per meter. Comp onents of the energy budget, C = F + U + P-g + P-r + R + M were measured du ring summer and winter months. None of the slopes of regressions of log(10) energy (J day(-1)) on log,,mass (g) was significantly different between sum mer and winter for any of the energy budget components, except those of som atic growth on mass. Summer y-intercepts were all significantly higher than winter y-intercepts, indicating that energy consumption and expenditure we re higher during the summer. Respiratory energy expenditure was the largest component of both summer and winter budgets. Activity accounted for 23% of total consumed energy during the summer and 13% during the winter.