440 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Age-fecundity data are presented in figure 11 

 and table 9 for the 113 sardines for which both 

 fecundity data and age data were available. 

 These show that the correlation between fecundity 

 and age is not so good as that between fecundity 

 and length or weight for these samples. Simpson 

 (1951) also found a poorer correlation between 

 age and fecundity than between fecundity and 

 length or weight for plaice. On the other hand, 

 Lehman (1953) obtained a better correlation be- 

 tween fecundity and age than between fecundity 

 and length or weight for shad. 



ONE AT 101.8 



Figure 11. — Relation between fecundity and age. 



Table 8. — Mean lengths of 9-year classes of sardines taken 

 in the 1945-46 commercial fishery at San Pedro 



Table 9. — Age-fecimdity regression data using formula 

 Y = a + bX (Y = No. of ova in most advanced mode: X = 

 No. of annuli ') 



1 Males and females. 



' Number of annuli+l = age. 



NUMBER OF SPAWNINGS PER YEAR 



The maturing ovaries of a sardine contain 

 yolked ova of two or more size groups. This 

 point was illustrated in figure 2. Clark (1934) 

 pointed out this fact and used it as a basis for 

 concluding that individual sardines spawn more 

 than once during each spawning season. As the 

 number of batches of ova spawned per season is 

 as critical a point in determinations of fecundity 

 as the number of ova spawned per batch, and 

 much more difficult to assess, I will review evi- 

 dence for and against multiple spawnings. 



The data presented in this paper are based on 

 sardines collected during the period November 

 1945 through February 1946. It is unlikely that 

 any of the sardines had spawned during this 

 period. These months, with the possible excep- 

 tions of January and February (when nominal 

 amounts of spawning have been found), are in 

 advance of the sardine spawning season in the 

 soutliern California area. As no samples were 

 available after February in 1946, the changes that 

 took place during and after the spawning season 

 could not be studied. However, some of the data 

 obtained from the January and February samples 

 do bear on the problem of multiple spawning, and 

 these will be summarized. 



It is assumed by workers on fecundity that only 

 ova in the most advanced mode will be spawned 

 at a given time or batch. Hence, the number of 

 ova in this mode is taken to represent tlie number 

 of ova spawned per batch. The ratio of number of 

 smaller yolked ova to number of ova in the most 

 advanced mode has been taken as an indication of 

 the number of batches that could potentially be 

 spawned in a season. The number of yolked ova 

 found in a mature ovary just prior to the initial 

 spawning of a season would represent the total 

 number of ova spawned in that season if (1) all 

 the yolked ova were subsequently matured and 

 spawned, and (2) if no ova were subsequently 

 added to the group of yolked ova. 



