Preferred temperature and critical thermal maxima of red abalone Haliotis rufescens

Cultured red abalone Haliotis rufescens from Isla de Todos Santos Baja California, Mexico, were used in evaluations of preferred temperature and critical thermal maxima (CTM). Organism weights ranged from 12.7 to 26.0 g and from 4.7 to 6.0 cm in length. The red abalone locates its preferred temperature by the orthothermokinesis mechanism and the preferred temperature was 18.8 degree C higher than optima previously reported for this species, higher than that of the South African abalones, but similar to the Australian abalones. The CTM of H. rufescens at 50% was 27.5 degree C which is similar to other abalone species (H. cracherodii, H. midae, H. rubra, and H. laevigata).