Seasonal energetics of Haliotis fulgens (Philippi) and Haliotis tuberculata (L.)

Bioenergetics (food ingestion, absorption, growth, respiration, ammonia, and mucus production) of the warm-water abalone Haliotis fulgens and the cold-water species H. tuberculata were studied under summer and winter conditions in the Gulf of Aqaba. Individuals of 38-45 mm shell length and 7-11 g whole live weight were fed Ulva lactuca and Gracilaria conferta. Food ingestion was greater in summer but not sufficient to overcome the high maintenance, resulting in low (H. fulgens) or no (H. tuberculata) growth in summer. Growth for H. fulgens and H. tuberculata during winter was 0.10 ± 0.05 mm/d and 0.09 ± 0.02 mm/d and 0.02 ± 0.01 and 0.03 ± 0.01 g DW/d, respectively. Respiration rate and ammonia excretion were greater in summer for both species. In summer, H. tuberculata had greater food absorption than H. fulgens, and the reverse was found in winter. Mucus secretion was only 1-9% of the energy budget. In winter, growth accounted for the majority of the energy budget of both species and in summer, respiration and ammonia were the main components. Overall, H. fulgens seems to be most suited to year-round conditions found in the Gulf of Aqaba.