06APRHt 



-2.0 



-1.0 -0.5 0.0 



TEMPERATURE DEVIATION (C) 



Figure 33. The relationship between the estimated annual date of peak abundance (y) of entrained winter flounder 

 larvae and the annual temperature deviation (x) during March-May with the fitted linear regression of: 

 y = 72.0 - 10.7 (x); r^ = 0.53. 



the retention time in the quarry with 2-unit operations was approximately 3 h, most larvae would survive 

 the thermal increase due to entrainment, but not necessarily any mechanical damage. 



The critical thermal maximum was determined by increasing the water temperature from 8 °C at a 

 rate of 1 °C per min until total mortality occurred. The critical thermal maximum was 25 to 26 °C for 

 pre-metamorphosed and 24 to 26 °C for metamorphosing larvae. Water temperatures in the quarry 

 generally reached or exceeded 24 °C by mid-May. Whether the critical thermal maximum temperature 

 actually represents the maximum temperature that larval winter flounder can survive is doubtful because 

 an almost 15 °C rise in less than 20 min would not provide a period for acclimation at each temperature. 

 Furthermore, the CTM may vary according to any particular acclimation temperature (NUSCo 1975). 



114 



