YELLOWTAIL FLOUNDER OFF NEW ENGLAND 



209 



Table 29. — Age composition, by quarters, of yellowtail 

 landed from the southern New England stock, 1942-47 



Table 30. — Estimated number of yelloivtail of each age, 

 landed from the southern New England stock, fourth 

 quarter of 1942 through 1947 



[In thousands of fish. Based on tables 21 and 29) 



Year and quarter 



Year 1942: 4th quar- 

 ter 



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 



Average. 1943-47: 



1st quarter 



2d quarter 



3d quarter 



4th quarter 



All years 



Percent 



Number of fish having- 



1 



annu- 



lus 



587 

 740 



235 

 ~~~8 



462 

 " ~19 



348 



16 



21 



385 



1.3 



2 



an- 

 nuli 



7,270 



3,643 



948 



2,554 



1,325 



2.796 

 251 

 691 

 425 



1,006 



110 



3.921 



2,706 



2,310 



840 



3,728 



3.685 



1,772 



668 



3,650 



3,723 



2,305 

 563 

 2,909 

 2,373 

 8,150 

 28.1 



6,684 



3.244 

 3,812 

 8,419 

 1,853 



3.914 



5,27' 



4,842 



910 



1,473 



520 



1,774 



1,414 



1,697 

 720 

 552 



1,447 



1,361 

 1,635 

 3,650 

 2,944 



2.338 

 2,393 

 3.847 

 1,714 

 10.292 

 35.5 



nuli 



1,764 



2,049 



1,483 



4,446 



985 



2.236 

 351 



1.186 

 373 



1,231 



536 



2.388 



2,394 



1,028 

 1,1 

 1.376 

 1.362 



616 



535 



951 



1.411 



1,432 



797 



2.069 



1,305 



5.603 



19.3 



5 



an- 

 nuli 



1,395 



1.025 

 702 

 568 

 399 



560 

 251 

 346 

 165 



579 



158 



534 



1, 103 



575 



360 



998 



2,155 



539 



905 



932 



1,119 



651 

 475 

 676 

 988 

 2,790 

 9.6 



nuli 



967 



457 



473 



94 



783 

 100 



489 



63 



199 



378 



254 



166 

 580 



385 

 483 

 408 

 876 



576 

 221 

 249 

 420 

 1,466 

 5. 1 



7+ 

 an- 

 nuli 



293 



167 

 94 



47 



189 

 40 

 211 



38 



200 



144 



78 

 195 



100 

 60 

 141 

 301 

 1.0 



To- 

 tal i 



18,801 



11,669 

 7,569 



16,553 

 4,714 



10,401 

 6,232 

 7,114 

 2,116 



4,970 

 1,575 

 8.909 

 8,229 



6,099 

 2.999 

 6,866 

 9.484 



5, 136 

 4,370 

 9.688 

 10,267 



7,655 

 4,549 

 9,826 

 6.962 

 28,992 



Good agreement appears between maximum 

 lengths observed and Walford's (1946) ultimate 

 length Zoo for the yellowtail. This characteristic 

 represents the length at which growth becomes 

 zero and is computed from 



h 



Zoo = 



\-k 



in which l t is the y intercept of a line fitting the 

 points {In, In + \),ln is the length at age n years 

 and k is the slope of the line. We have used the 

 mean attained length by quarters from table 26, 

 fitted lines by the least-squares method to deter- 

 mine 1, and k, and estimated Zoo, for each quarter 

 and sex. (We have omitted females age 7 years 

 and older from the computation because this 

 group contains older fish and probably has a high- 

 er average mean length than a group composed 

 only of females age 7 would have.) The results 

 (table 31) show reasonably good agreement with 

 the maximum size observed in the length samples 

 which comprised 38,335 fish from the fourth 

 quarter of 1942 through 1947. If we assume that 

 the samples from different quarters represent dif- 

 ferent populations and the estimates of Zoo con- 

 tain sampling variation, it is permissible to aver- 

 age them. Thus, we find that the mean estimate 

 of Zoo for males is 1.1 cm. lower and for females 

 2.0 cm. higher than the observed measurements. 

 Moreover, the estimates of Zoo from these data, 

 particularly for males, are probably low because 

 the fishery undoubtedly oversamples the larger 

 fish in the younger age groups. This results in a 

 high value for l s , and perhaps for l„ and corre- 

 spondingly lower values for k and Zoo. Neverthe- 

 less, the close agreement gives us further confi- 

 dence in our age readings and length samplings. 



Table 31. — Ultimate length (1°°) and maximum length 

 found in samples of the catch (lm), from the southern New 

 England stock, by quarter and sex 



[In centimeters] 



1 Slight discrepancies occur due to rounding off of the figures. 



From appendix C, pp. 244-5. recorded in centimeter groups. 



