SMITH and DAIBER: BIOLOGY OF SUMMER FLOUNDER 

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TOTAL LENGTH (CM) 



FIGURE 3. — Total length-frequency distribution for 149 male and 202 female summer flounder caught in Delaware Bay in 1966 and 



1968. 



We found no significant difference in growth rates 

 between the sexes, although both Poole (1961) and 

 Eldridge (1962) did report a significant difference. 

 The growth rates probably are significantly differ- 

 ent, an indication of this being the large differ- 

 ence in predicted maximum lengths from Wal- 

 ford's growth transformation (62 cm for males and 

 88 cm for females), but our limited sample size in 

 older age-groups, particularly males, prevented 

 this difference from being significant. The percent 

 increase in annual length (Tables 2, 3) is similar 

 for both sexes until age 6, and then it begins to 

 decline more rapidly in males. 



Our calculated growth rates underestimate 

 those actually observed. Bigelow and Schroeder 

 (1953) stated that the largest summer flounder for 

 which they could find a definite record weighed 

 11,793 g (26 lb), and the largest fish recorded in 

 sport fishing was 94 cm (37 in) long and weighed 

 9,072 g (20 lb). Using our predicted maximum 

 lengths and length-weight relationship (see next 

 section), we calculated that a male 62 cm (24.4 in) 

 would weigh 2,339 g (5.21 lb) and a female 88 cm 

 (34.7 in) would weigh 8,199 g (18.1 lb). Also our 

 predicted length of 14 cm at age 1 ( Y-axis intercept 

 from Walford's growth transformation) is 3 cm 



smaller than the observed length given by El- 

 dridge (1962). The lack of samples from age-group 

 1 and above age-group 8 and the limited samples 

 in age-groups 6 through 8 might account for most 

 of this error. A small change in the female growth 

 rate would give a predicted maximum length of 98 

 cm, and then we have a fish weighing 11,793 g (26 

 lb). The growth rate offish in age-groups 2 through 

 5 may approximate the growth of the same age- 

 groups in the actual population. 



LENGTH AND 

 WEIGHT RELATIONSHIPS 



A linear relationship existed between total 

 length-standard length (Table 4), standard 

 length-head length, and head length-upper jaw 

 length. There were no significant differences in 

 these relationships when the sexes are consid- 

 ered separately. The slope (3.151) of the line rep- 

 resenting the total length-weight relationship 

 (Table 4) was not significantly different from that 

 (3.146) reported by Lux and Porter (1966) for 

 summer flounder caught in June off Mas- 

 sachusetts. They found no difference between the 

 slopes of the lines when sex was considered, but 



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