PARRISH ET AL.: AGE DEPENDENT FECUNDITY IN NORTHERN ANCHOVY 



the condition was too poor to allow sex identifica- 

 tion. The relationship between age and the percent- 

 age of unsexed fish is similar to that described for 

 size (Table 2). It should be noted that both data sets 

 are biased towards larger and older fish. The age 

 composition of anchovy in the midwater trawl data 

 is biased because of the fact that otoliths were often 

 not taken when trawl hauls were dominated by 

 young-of-the-year fish (Parrish et al. 1985). The 

 purse seine data contain a much smaller percentage 

 of small or young fish than the midwater trawl data. 

 This is primarily caused by the fact that a 5-in (about 

 108 mm SL) minimum size limit was in effect for 

 most of the 1966-80 period. 



To evaluate the seasonal cycle of the occurrence 

 of northern anchovy for which the sex could not be 

 identified, the monthly percentages of females, 

 males, and anchovy with unknown sex were deter- 

 mined by age group for the San Pedro fishery (Fig. 



1). In all age groups the minimum percentages of 

 fish which could not be sexed occurred from about 

 January to May in association with the spawning 

 season. Higher percentages occurred both before 

 and after the spawning season, particularly in the 

 first potential spawning season. This implies that 

 a significant percentage of anchovy mature, or at 

 least partially mature, and then reabsorb their 

 gonadal tissue to the point that their gonads are so 

 small that they cannot be sexed without magnifica- 

 tion. It also implies that a bias due to the unsexed 

 fish exists. This bias is at a minimum from January 

 to May and it primarily affects the analyses of fish 

 in their first potential spawning season. 



Klingbeil (1978) found the female:male ratios of 

 northern anchovy sampled in the Sea Survey Pro- 

 gram and in the commercial fishery to be 1.03:1 and 

 1.60:1 respectively. The additional years of infor- 

 mation from these two sources, in our data sets, pro- 



Table 2.— Proportion of northern anchovies with unknown sex and sex ratio by size (A) and 



by age (B). 



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