Temperature tolerance of Haliotis diversicolor supertexta at different salinity and temperature levels

Abstract

Juvenile abalone Haliotis diversicolor supertexta Lischke at different environmental regimes (25, 30 and 35 psu at 20, 25 and 30°C) were examined for their temperature tolerances by increasing and decreasing temperature at a rate of 1°C h −1. They were also examined for UTTL (upper temperature tolerance limit) and LTTL (lower temperature tolerance limit) when transferred directly into a series of higher temperature (30–36°C) and lower temperature (5–15°C) water baths. The CTMax (critical thermal maximum), CTMin (critical thermal minimum), UTTL and LTTL increased directly with temperature, but were inversely related to salinity. H. diversicolor supertexta juveniles maintained at 35 psu at 20, 25, 30°C have 50% CTMin of 1.8, 3.9, 8.7°C and have 50% CTMax of 34.1, 35.3, 37.3°C, respectively. The juveniles maintained in 20°C and 35 psu survived temperature of 3.5–32.7°C, and those maintained in 30°C and 25 psu survived temperature of 14.0–36.8°C, when temperature was decreased or increased gradually. The juveniles maintained at 30°C and salinity of 25 psu have the ability to tolerate temperature as high as 36.8°C, and those maintained at 20°C and salinity of 35 psu have the ability to tolerate temperature as low as 3.5°C.