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Fishery Bulletin 95(2), 1997 
seasonal production and distribution of sardine lar- 
vae and their nutritional condition were determined 
during these cruises as were the spatial and tempo- 
ral distributional patterns of larvae in relation to 
hydrographic and biological parameters. During the 
first 3 cruises, additional transects were located in 
French waters to estimate the extension of spawn- 
ing in the northeastern area of the Cantabrian Sea. 
In the western area, spawning during these months 
is very low from Cape Finisterre southwards (Garcia 
et al., 1992); therefore sampling was curtailed at the 
Portuguese border. The sampling design for the 
present study did not cover, either spatially or tem- 
porally, spawning along the entire Iberian peninsula, 
because sampling on the Portuguese shelf during 
winter was not possible owing to logistical reasons. 
Sampling of this area was not considered important 
because other studies (Robles et al., 1992; Cabanas 
et al. 8 ; Roy et al. 9 ) have suggested that recruitment 
8 Cabanas, J. M., C. Porteiro, and M. Varela. 1989. A possible 
relation between sardine fisheries and oceanographic conditions 
in NW Spanish coastal waters. ICES Council Meeting 1989/ 
H:18, 12 p. (mimeo). 
9 Roy, P., C. Porteiro, and J. M. Cabanas. 1993. The optimal 
environmental window hypothesis in the ICES area: the ex- 
ample of the Iberian sardine. ICES Council Meeting 1993/L:76, 
13 p. (mimeo). 
of the Atlanto-Iberian sardine stock depends mainly 
on spring spawning in the Cantabrian Sea, as well 
as on upwelling features along the west coast of the 
Iberian peninsula. 
Results 
The length distribution of a subsample of 220 juve- 
niles used for the birthdate analysis was not signifi- 
cantly different from that of the entire sample of 
1,100 juveniles (Kolmogorov-Smirnov test, P>0.2). Of 
these 220 juveniles, 3 were rejected because daily 
rings were not visible in more than 5% of the transect 
readings. The age of the remaining 217 fishes ranged 
from 151 to 298 days, with birthdates from 13 De- 
cember 1991 to 2 April 1992 (Fig. 2). Data by sample 
date are shown in Table 1. The average birthdate of 
juveniles from La Coruna was 28 January 1992 
(n- 98, SD=19 d, birthdate range: 13 December 1991 
to 2 April 1992), and the average birthdate of juve- 
niles from Vigo was 6 February 1992 (n=119, SD=16 
d, birthdate range: 23 December 1991 to 26 March 
1992). The observed differences between the two 
birthdate distributions (Fig. 2) were significant 
(Kolmogorov-Smirnov test, P<0.001). Specimens 
younger than 5 months were not caught by the fish- 
