202 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Rate of Growth 



Growth data have been developed from the at- 

 tained length at time of capture of 9,204 yellow- 

 tail for which the ages were determined from 

 scales. These fish were included in the samples 

 collected from 1942 to 1947. The data are listed 

 in detail in appendix D, p. 246, and summarized 

 in table 25. The mean length of each age group 

 in each calendar quarter during which 10 or more 

 age determinations were obtained has been com- 

 puted (table 26) . It may be recalled that we have 

 assumed that the annulus is complete on March 

 31, and therefore the yellowtail's year of life does 

 not correspond to the calendar year. The first 

 quarter in the fish's year is the second quarter in 

 the calendar year. For example, the 2-annuli, 

 male yellowtail that averaged 32 cm. in the fourth 

 quarter of 1942 were actually in the third quarter 

 of their third year of life. 



The average attained length for each quarter 

 of the yellowtail's life is plotted in figure 17. It is 

 readily apparent from this chart that the females 



Table 25. — Number of age determinations of yellowtail, 

 by sex and quarter, from the southern New England stock, 

 1942-^7 



Year and quarter 



Year 1942: 



1st quarter -. 



2d quarter. . 



3d quarter.. 



4th quarter.. 

 Year 1943: 



1st quarter . 



2d quarter.. 



3d quarter. . 



4th quarter. 

 Year 1944: 



1st quarter . 



2d quarter. . 



3d quarter.. 



4th quarter- 

 Year 1945: 



1st quarter. - 



2d quarter. . 



3d quarter. . 



4th quarter . 

 Year 1946: 



1st quarter.. 



2d quarter. . 



3d quarter. . 



4th quarter. 

 Year 1947: 



1st quarter. . 



2d quarter. . 



3d quarter.. 



4th quarter. 



Total 



Male 



23 



160 



20 

 56 

 46 



77 



298 

 39 

 256 

 264 



239 

 13 



326 

 326 



79 

 146 

 149 

 144 



2.791 



Female 



49 

 430 

 145 



81 



30 

 68 

 85 

 167 



586 



61 



412 



475 



408 



12 



582 



572 



121 



279 

 350 

 278 



5.256 



Undeter- 

 mined 

 sex 



368 

 74 



158 



1.157 



Total 



25 

 368 



74 

 256 



205 

 679 

 175 

 402 



93 

 124 

 144 

 244 



884 

 100 



647 

 25 



908 



200 

 425 

 499 

 422 



9.204 



Table 26. — Mean lengths of yellowtail at time of capture, by sex and age, from southern New England stock, 1942-47 



[Computed from 10 or more age determinations] 



