NOTE Witherell and Burnett: Growth and maturation of Pleuronectes amencanus 



817 



Cape Cod) were successfully aged and assigned matu- 

 rity stages. Ages ranged from 1 to 16 years in the south- 

 ern stock, and 1 to 15 years in the northern stock. For 

 both stocks, females predominated at ages 3 and older 

 (Fig. 1). 



Growth rates of winter flounder differed for each gen- 

 der and stock unit. Females grew faster than males, and 

 obtained larger mean asymptotic lengths (Fig. 2). For 



each gender, winter flounder from the south- 

 em stock were generally larger at age than 

 those from the northern stock, at ages 3-8. 

 Mean lengths at age observed from our 

 samples were similar to, but slightly smaller 

 than, those determined from 1964-68 tag re- 

 turn data (Table 1). 



For both stocks and sexes, maturation 

 generally began at age 3 and was nearly 

 complete at age 5. Maturation of age-3 and 

 age-4 fish was quite variable and was some- 

 what sensitive to size at age (Fig. 3). Owing 

 to their somewhat faster growth rate, win- 

 ter flounder matured at younger ages south 

 of Cape Cod. For females, A 50 's (and corre- 

 sponding L 50 's) were 3.0 years (28.3 cm) 

 south of Cape Cod and 3.3 years (28.7cm) 

 north of Cape Cod. For males, A 50 's (and 

 corresponding L 5l ,'s) were 3.1 years (28cm) south of 

 Cape Cod and 3.3 years (27.2 cm) north of Cape Cod. 



Discussion 



Adult winter flounder south and east of Cape Cod were 

 larger at age than adults from other coastal popula- 

 tions. For example, age-5 female winter flounder in 



