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Fishery Bulletin 95(4), I 997 
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0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 
Body depth to standard length ratio 
- 
1988 
Spring 
1 1 Summer 
n = 3,372 
_l 1 1 1 11 
i r i i i 
i - 
1989 
[■1 Spring 
1 1 Summer 
n = 1 ,245 
t B 
Figure 3 
Body depth to standard length-frequency histograms for Peprilus 
triacanthus collected during the spring and summer of 1988 and 
1989. Frame- and Tucker-trawl collections were combined. 
mens sampled had 11 to 17 ventral midline melano- 
phores, and 94% had 10 to 16 melanophores. These 
data suggest the presence of P. triacanthus in our 
samples. On further analysis of pigment patterns, we 
found no difference among specimens (Rotunno, 1992). 
These data corroborate our caudal vertebral counts. 
OtoSith marking experiment 
Daily increment formation was a valid indicator of 
age of Peprilus spp.. The presence of subdaily incre- 
ments was also noted in these otoliths. The number 
of increments observed after the tetracycline mark 
regressed against the number of days since marking 
showed a 1:1 correspondence (Fig. 5). Ay-intercept 
value of zero was assigned to the regression. The 
slope of the regression (0.921) did not differ signifi- 
cantly from unity (/-test: t= 0.82, P=0.42). 
Growth and hatching date 
Spring and summer growth rates were estimated 
from 1988 collections of Peprilus at 0.233 mm/day 
and 0.219 mm/day, respectively. These growth rates 
were not significantly different (F=2.071, P=0.155). 
Therefore, seasons were combined and an overall 
regression was computed that yielded an average 
growth rate of 0.225 mm/day (Fig. 6). The regression 
equation (Age = 3.433(SL) + 8.270, r 2 = 0.93) was used 
to backcalculate hatching dates from length frequen- 
cies. This age-length relation was also applied to 1989 
collections for back-calculation purposes. 
