The effect of activity, in the form of increased respiratory energy expenditure and secretion of mucus, on the summer and winter energy budgets of Haliotis kamtschatkana was assessed. Abalone exhibited seasonal variations in field activity with 20% of all individuals observed crawling during June to October, compared with -1 quiescent 12.0 h day-1 alert. O.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 alert, 2.3 h day-1 feeding, and o.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. Components of the energy budget, C = F + U + Pg + Pr + R + M were measured during summer and winter months. None of the slopes of regression of log10energy (J day-1) on log10mass (g) was significantly different between summer and winter for any of the energy budget components, except those of somatic growth on mass. Summer y-intercepts were all significantly higher than winter y-intercepts, indicating that energy consumption and expenditure were 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.