Effect of acclimation temperature and heat shock on vulnerability of fry of lake whitefish (Coregonus clupeaformis) to predation

Fry of lake whitefish (Coregonus clupeaformis) acclimated to 10, 15, and 18 C were exposed to temperatures of 24.5, 25, and 28 C for 1 min and then immediately returned to water at their acclimation temperature, in test tanks containing yearling yellow perch (Perca flavescens). The number of attacks on the fry and the number captured and eaten in 30 min were recorded in separate tests of shocked and unshocked (control) whitefish.Significantly more whitefish were captured per attack (data for shocked and unshocked fry combined) at 15 and 18 C than at 10 C; and shocked fry were significantly more vulnerable to capture by the perch than were unshocked controls.