Thermal Shock and Pulsed Exposure on Silver Carp, Bighead Carp, Grass Carp and Common Carp: Lethal Response and Recovery Effect

Abstract

Thermal shock results demonstrated that the TL50 values (the incipient lethal temperature) of four freshwater fishes increased with increasing acclimation temperature. The UILT values (upper incipient lethal temperature) for silver carp (Hypophthal michthys molitrix), bighead carp (Aristichths nobilis), grass carp (Ctenopharyngodon idellus) and common carp (Cyprinus carpo) were 36.6℃, 35.1℃, 37.2℃ and 36.8℃, respectively. Pulsed experiment data showed similar type of heat acclimation for CTMax (critical temperature maximum) and LRR (loss of equilibrium and inverted swimming). CTMax, LRR and TL50 indicate the importance of acclimation temperature relative to their upper thermal tolerance limits of fishes. The effects of thermal stress on silver carp, bighead carp, grass carp and common carp were dependent upon acclimation temperature and the degree of influence can be inferred through the change of TL50, UILT, LRR, CTMax.