functional regression and used to convert standard to total length for 

 data analysis. 



The mortality rate of juveniles was calculated using a method 

 described by Jones (1981). The natural logarithms of the total number 

 of fish caught that were equal to or larger than a series of specific 

 lengths were plotted against the logarithms of U° minus those lengths; 

 the slope was Z/K. Both La> and K are parameters of the von Bertalanffy 

 growth model and Z is the instantaneous rate of total morality. The 

 growth model was fit by methods outlined previously in this section 

 using the weekly length measurements of specimens from station LR. As 

 weekly data were used, the time unit for the model parameters was 1 week 

 and Z represented the weekly rate of instantaneous mortality. 

 Asymptotic maximum length was assumed to be the length achieved as 

 growth ceased in early fall. Length-frequency distributions were 

 examined for each of the four tow lengths (40-100 m) used during the 

 sampling and numbers per each 2.5-mm interval were adjusted upwards as 

 necessary to give the catch per 100 m^. Total catch for each 2.5-mm 

 interval was found by summing across all the length frequencies. These 

 data were used with the growth model parameters in a regression to 

 calculate Z; annual survival was estimated as exp((-Z) (52) ) and daily 

 survival as exp(-Z/7). 



Impingement 



The number of winter flounder impinged on the traveling screens of 

 MNPS from October 1972 through September 1983 was estimated using 

 techniques described in detail in the Fish Ecology section of this 

 report. Length-frequency data of fish impinged from 1976-77 through 

 1982-83 were also examined. 



Entrainment 



Annual entrainment estimates from 1976 through 1983 were calculated 

 using the median density (n/500 m^) of winter flounder larvae collected 

 at station EN during the larval season. The entrainment estimate was 

 the median value times the total number of 500 m^ units of seawater 



12 



