This study determined the preferred temperature, critical threshold limits, represented by critical thermal maximum (CTMax) and critical thermal minimum (CTMin ), thermal window width, and thermal metabolic scope of two hybrid of abalones Haliotis rufescens x H.fulgens (RB) and H. rufescens x H. corrugata (RP) acclimated to 18, 21, and 23°C ± 1°C. The preferred temperature was obtained for both hybrids by the gravitational method. It was not significantly different (P < 0.05) in the day and night cycle for both hybrids, being 22.7 ± 1.9°C for RB and 22.6 ± 1.2°C for RP.
Acclimation temperature significantly affected (P<0.07). The thermal tolerance represented for CTMax and CTMin of both hybrid abalones increased with acclimation temperature. The thermal window was wider for RB (166.2°C2) than that obtained for RP (125.5°C2). The thermal metabolic scope obtained for RB hybrid had a mean value of 262.2 mg O2 h-1 kg-1 w.w. and for RP was 191.4 mg O2 h-1 kg-1 w.w. with a range of optimal physiological performance that closely matches the environmental conditions where it can be farmed. Therefore, the highest value of the thermal aerobic scopes corresponded to the intervals of the preferred temperature obtained for both hybrid abalones. These results may partially explain their distribution pattern, as well as their aquaculture potential in temperate regions.