SEPT OCT 



Figure 20. Weekly mean length (+ 2 standard errors) of 

 juvenile winter flounder taken at station 

 LR in the Niantic River during 1983. 



or two groups of a few larger individuals each week. Juveniles were 

 significantly smaller at CO than those at LR because little or no 

 overlap occurred in the error bars around the weekly mean lengths. By 

 August the smallest individuals at LR were larger than 50 mm whereas 

 specimens of 30 to 40 mm were still being taken at CO. 



Weekly mean lengths at CH were generally similar to or somewhat 

 less than those at LR; smaller sample sizes resulted in greater observed 

 variability. The few juveniles taken at SP included some of the largest 

 specimens taken during the sampling (up to 104.5 mm). This was similar 

 to Pearcy (1962) who also found largest juveniles farthest upriver. 



Since a plot of the mean weekly lengths of juveniles at LR appeared 

 to follow a classic form of a growth curve, the von Bertalanffy growth 

 model was fit to the data (Table 16). A good fit was obtained (n=716; 

 R^=0.80) and the L"" (coincidentally, the same as the calculated lengths 

 for age 1) and K parameters were used with length frequencies to 

 calculate the instantaneous mortality coefficient (Z) according to the 

 method of Jones (1981). A daily total mortality rate of 2.97% was 

 derived from these calculations. This value, equivalent to an average 



47 



