701 

 60 

 I 50 



X 



I 40 



LiJ 



i^ 30 

 if, 20 



10 



1985 



HA-h-l 



MAY JUNE 



JULY 



AUGUST SEPTEMBER 



Figure 25. cont. 



The instantaneous mortality rate (Z) of post-larval winter flounder was previously reported (NUSCo 

 1984, 1985, 1986a) using a method described by Jones (1981). Parameters required for this procedure 

 included the cumulative catch of young by length increment and the parameter K of the previously 

 described von BertalanfFy growth model. For young, /.oo of the model was fixed at 95 mm for LR and 

 75 mm for WA fish, or slightly larger than the length of the largest specimen found at each of the stations 

 (NlJSCo 1986a). Although not included in this report, analysis of data collected in 1986 indicated that 

 selection of a fixed Loo and the maimer in which the cumulative length increments were chosen most likely 

 biased estimates of Z. Therefore, catch curves were constructed using annual abundance data from LR 

 for 1983-85 and WA for 1985. No analysis was attempted for CO due to sampling problems affecting 

 abundance estimates. The catch curve method may also be criticized as young were assumed to have 

 comprised a single-age cohort which was followed from week to week during the sampling season. 



95 



