YELLOWTAIL FLOUNDER OFF NEW ENGLAND 



187 



ing to the calendar quarter shows excellent agree- 

 ment, with the maximum discrepancy between 

 measurements and landings being only 2.3 per- 

 cent. The effect of these maldistributions on the 

 average is very slight. The average size of the 

 yellowtail measured from 1943 through 1947 was 

 35.87 cm. If the average lengths by area are com- 

 puted separately and weighted according to the 

 quantity landed from each area, the overall aver- 

 age is decreased only 0.18 cm. Similarly, if we 

 separate the measurements according to the year 

 and weight them according to quantities landed, 

 the overall average is increased by only 0.14 cm. 

 Finally, computations according to quarter show 

 even less change, 0.03 cm. Because of these very 

 small differences, we present the average length 

 compositions in the ensuing pages on the basis of 

 the actual number measured, and we consider 

 them representative. 



Table 9. — Quantities of yellowtail landed and numbers 

 measured, by area, quarter, and year, 1943-47 



1 Slight discrepancies occur because of rounding off of the figures. 

 ' Includes data from 4th quarter in 1942. 



The samples obtained during 1941 and 1942 

 were less representative than later samples; they 

 were taken as opportunity afforded and sex data 

 are lacking. No attempt was made to sample 

 more heavily during the seasons witli heavy land- 

 ings, and the third quarter of 1942, with the 

 heaviest landings in the history of the yellowtail 

 fishery, was not sampled at all. Thus, these length 

 compositions are not fully representative and res- 

 ervations will be made in using them. 



22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 



LENGTH -CENTIMETERS 



Figure 7. — Length composition, by sex, of the yellowtail 

 from the southern New England stock, 1943 through 

 1947. 



The predominance of the females in the land- 

 ings from 1943 through 1947 with respect to both 

 numbers and length is shown in table 10 and fig- 

 ure 7. The females accounted for 65.33 percent of 

 the total number in the samples. The grand aver- 

 age length of the sexes combined was 35.87 cm.; 

 the females averaged 37.21 cm., whereas the males 

 averaged only 33.34 cm. It will be shown that 

 this difference in size is caused by a difference be- 

 tween the sexes in rate of growth, which appar- 

 ently also results in the preponderance in num- 

 bers of females in the catch. In table 10 it may 

 be seen that above 33 cm. the females were more 

 numerous in the landings; under 33 cm. the 

 males were more numerous. It may be judged 

 also from the curves in figure 7 that the fishery is 

 fully utilizing only male yellowtail more than 33 

 cm. or females more than about 40 cm. in length, 

 if we assume that this species decreases normally 

 in numbers as it increases in size. However, if 

 the total curve is considered, it may be judged 

 that both sexes are fully available when more than 



