5i 



CO 

 CD 

 O 4 



fe  



CO 



F; 62,150 G c 

 r = .941 



- ii ii m i ii 1 1 1 n 



|inii ii| i i i 

 50 100 



i I i i i i i i i i i I t ' 

 200 300 



400 



OVARY WEIGHT (g) 



FIGURE 3. — Yellowtail fecundity plotted against ovary weight, 

 and the fitted curve for southern New England. 



using an analysis of covariance (Snedecor and 

 Cochran 1967). 



We compared our data with those of Pitt (1971) 

 for the Grand Bank stock (lengths 37-54 cm, 

 ages 5-12 yr) using analysis of covariance. The 

 slopes of fecundity vs. length and fecundity vs. age 

 regression lines were not significantly different 

 (P>0.25) (Figures 1, 2). This indicates that the 

 rate with which fecundity increased with both 

 length and age was not significantly different be- 

 tween the two populations. However, the inter- 

 cepts of the fecundity vs. length regressions were 

 significantly different (F = 8.67; df = 1, 94; 

 P<0.01), southern New England fish being more 

 fecund for a given length than Grand Bank fish 

 (Figure 1). In addition, the intercepts of the fecun- 

 dity vs. age regressions were significantly differ- 

 ent (F = 28.87; df = 1,92; P<<0.005) indicating 

 that southern New England fish were more fecund 

 for a given age (Figure 2). 



There may be several reasons why fecundity is 

 higher at a given length and age in the southern 

 New England stock. Several authors including 

 Hodder (1965), Bagenal (1969), and Tyler and 

 Dunn (1976) have suggested that both nutrition 

 and temperature can affect egg production. Little 

 is known about the type and amount of food avail- 

 able to the two populations so no speculation can 

 be made about the possible nutritional effects on 

 fecundity in this species. Water temperatures in- 

 habited by the two stocks are different. Southern 

 New England yellowtail flounder inhabit waters 

 of 4.9-12.3°C (Royce et al. 1959), while Grand 

 Bank yellowtail flounder are found at tempera- 

 tures of -l°to 6.5°C (Pitt 1974). Pitt (1974) found 

 that the southern New England population grew 

 faster than the Grand Bank population, probably 



due to these warmer temperatures. This acceler- 

 ated growth rate apparently results in earlier 

 maturation of the southern New England fish, 

 50% of the females being mature at 2-3 yr old and 

 32 cm long (Royce et al. 1959) as compared with 

 5-6 yr and 37 cm long for Grand Bank females 

 (Pitt 1970). Simpson (1951) found that faster 

 growing plaice were more fecund for a given age 

 and length. Likewise, Pitt (1964) found that in 

 American plaice of comparable ages, ovaries of 

 faster growing fish were larger than those of 

 slower growing individuals, and fecundity was 

 higher. If the ovaries of the faster growing south- 

 ern New England yellowtail flounder are larger at 

 comparable ages and lengths than those of Grand 

 Bank fish, we would expect southern New Eng- 

 land fish to be more fecund, as was the case. The 

 ecological implications of this higher fecundity are 

 unknown and require further study. 



Acknowledgments 



We thank Robert Livingstone and Judith Pent- 

 tila of the Northeast Fisheries Center, NMFS, 

 NOAA, Woods Hole, who generously provided us 

 with ovaries and ages of some yellowtail flounder. 

 Thanks go to T. K. Pitt who provided us with the 

 raw data necessary to compare the two stocks, and 

 to S-. B. Saila and W. H. Krueger of the University 

 of Rhode Island who critically read the manu- 

 script. 



Literature Cited 



BAGENAL, T. B. 



1969. The relationship between food supply and fecundity 

 in brown trout Salmo trutta L. J. Fish Biol. 1:167-182. 



HODDER, V. M. 



1965. The possible effects of temperature on the fecundity 

 of Grand Bank haddock. Int. Comm. Northwest Atl. Spec. 

 Publ. 6:515-522. 

 PITT, T. K. 



1964. Fecundity of the American plaice, Hippoglossoid.es 

 platessoid.es (Fabr.) from Grand Bank and Newfoundland 

 areas. J. Fish. Res. Board Can. 21:597-612. 



1970. Distribution, abundance, and spawning of yellow- 

 tail flounder, Limanda ferrunginea, in the Newfoundland 

 area of the northwest Atlantic. J. Fish. Res. Board Can. 

 27:2261-2271. 



1971. Fecundity of the yellowtail flounder [Limanda fer- 

 ruginea) from the Grand Bank, Newfoundland. J. Fish. 

 Res. Board Can. 31:1800-1802. 



ROYCE, W. F., R. J. BULLER, AND E. D. PREMETZ. 



1959. Decline of the yellowtail flounder Limanda ferrun- 

 ginea off New England. U.S. Fish Wildl. Serv., Fish. 

 Bull. 59:169-267. 

 SCOTT, D. M. 



1954. A comparative study of the yellowtail flounder from 



879 



