FISHERY BULLETIN: VOL. 71, NO. 2 



fish length at capture (Fraser, 1916). Two 

 scales were measured for each fish. A nomo- 

 graph was used to facilitate computations 

 (Carlander and Smith, 1944). 



For the value of C an estimated fish length 

 at scale formation of 20 mm was used. This 

 was based on examination of winter flounder 

 17 to 25 mm long collected in Massachusetts 

 coastal waters in early June 1962 (Lux and 

 Nichy, 1971). I have assumed that scale 

 formation occurs at about the same length on 

 Georges Bank where I have collected no fish of 

 the above sizes. 



Evidence, indicating that marks identified 

 as annuli on the scales of winter flounder from 

 Georges Bank were actual year marks, was 

 obtained from several sources. The main lines 

 of this evidence are summarized below. 



1. There is a correlation between age and 

 size in that increase in number of annuli 

 is accompanied by an increase in fish size 

 (Figure 5). 



2. Lengths at various annuli calculated from 

 scales correspond with empirical lengths 



2 



X £0 



FEMALE 



AGE IN YEARS 



at the same ages determined from reading 

 scales (Figure 5). 



3. There is agreement on length at age of 

 fish from the same age-groups collected in 

 different years (Table 2) and agreement 

 on calculated growth among different year 

 classes (Tables 3 and 4). 



4. Distinguishing permanent marks consist- 

 ing of unpigmented spots on the eyed side 

 of the fish occurred in successive years in 

 an estimated 4 to 13% of winter flounder 

 from the 1959 year class on eastern 

 Georges Bank (Lux, in press). This white 

 spotting appears to occur in far less than 

 1% of the fish of a year class normally. 

 White-spotted fish of the 1959 year class 

 were collected in 1964, 1965, and 1966. 

 Those from 1964 had 5 annuli on their 

 scales; those from 1965, 6 annuli, and 

 those from 1966, 7 annuli, showing that 

 1 annulus was added each year. The mean 

 lengths of spotted fish from this year 

 class showed regular increases over these 

 3 years (Table 5). Growth rate was unaf- 

 fected by white spotting. 



Table 2. — Number (n) of fish in each sample and mean 

 length in centimeters (cm) at capture by age group for 

 male and female winter flounder from eastern Georges 

 Bank in 1963-66. 



Figure 5. — Mean length at age from scale age deter- 

 minations (dots) compared with mean calculated length 

 at each annulus (open circles) for male and female 

 winter flounder from eastern Georges Bank. 



508 



