0.001); smaller fish appear to have an earlier, 

 and possibly shorter, spawning season. Prehm- 

 inary data on Dover sole collected in Cahfornia 

 indicated that larger fish still contained eggs in 

 late spring (Hunter'*), thus supporting our 

 findings. 



From those fish assessed for state of maturity, 

 a subsample of 162 was selected for age deter- 

 mination. All were mature; 78% were spent, and 

 22% contained advanced, yolked oocytes. Fish 

 were 5-24 years old (Fig. 4). As expected from 

 the length at maturity analysis, most (77.1%) of 

 the 35 fish with advanced oocytes were older 

 than 10 years of age; 53.5% of the spent fish were 

 older than 10 years. 



Discussion 



One cannot conclude unequivocally that the 

 estimated number of advanced oocytes prior to 



■•j. Hunter, Southwest Fisheries Center, National Marine Fisher- 

 ies Service, NOAA. P.O. Box 271, La Jolla, CA, 92038, pers. 

 commun. June 1986. 



spawning corresponds to reproductive output of 

 Dover sole, owing to incomplete spawning 

 events or resorption of oocytes (Foucher and 

 Beamish 1980). In addition, considering that 20% 

 of the females collected for fecundity estimates 

 during December were spent, some fish with 

 advanced ovaries may have partially spawned. If 

 so, fecundity would have been underestimated 

 for those fish. We maintain that our data reflect 

 the potential fecundity of Dover sole for the fol- 

 lowing reasons: 1) oocyte size distributions did 

 not demonstrate a distinct spawning batch 

 (oocyte diameter >1.80 mm), suggesting that 

 these females had not yet spawned; 2) no 

 hydrated oocytes were observed in the ovaries 

 used for fecundity estimates, although hydration 

 could occur rapidly and therefore its absence 

 could be a sampling artifact; and 3) our coeffi- 

 cients of determination for regressions of fe- 

 cundity on length and on weight are relatively 

 high (r^ = 0.82 and 0.81, respectively); if a signif- 

 icant number of oocytes had been released, vari- 

 ability could have conceivably been much 

 greater. An additional source of underestimation 



30 



25 



20 



>- 

 o 



-z. 



LjJ 



3 15 



o 



UJ 



cr 



10 



oO 



11 'r '■! 



D Spent 



H Mature, developing 



[' T "I ' '1 " ' r' ' r I 'r i V i i 'r 



15 



AGE (years) 



20 



24 



Figure 4. — Age-frequency distribution of 162 female Dover sole, classified as 

 either mature with advanced oocytes, or mature and spent. 



993 



