NOTES 



REPRODUCTIVE PARAMETERS OF THE 

 OFFSHORE SPOTTED DOLPHIN, 



A GEOGRAPHICAL FORM OF 

 STENELLA ATTENUATA, IN THE 



EASTERN TROPICAL PACIFIC, 1973-75 



Perrin et al. (1976) presented estimates of repro- 

 ductive parameters of the offshore population of 

 Stenella attenuate in the eastern Pacific based on 

 data collected in 1968-73, inclusive. The sample 

 included 3,527 specimens. Only the 1973 sample 

 (2,036) was putatively cross-sectional with re- 

 spect to age and sex structures of the kill; in ear- 

 lier years, adult females were selected for exami- 

 nation. The purpose of this paper is to present 

 analyses of samples collected in uniform fashion 

 in 1973, 1974, and 1975, updating the prior report 

 and providing a uniformly developed, albeit short, 

 time series of annual estimates. 



Methods and Materials 



The data and specimens were collected by 

 NMFS biological technicians aboard commercial 

 tuna vessels. Data collection procedures were the 

 same as described by Perrin et al. (1976). Data on 

 S. attenuata were collected on 24 cruises in 1973, 

 33 in 1974, and 32 in 1975. 



The total sample includes 6,243 specimens, 

 6,168 from precisely known localities (Figure 1). 

 Because of the seasonal nature of the fishery, the 

 sample is heavily biased toward the first half of 

 the calendar year with practically no coverage of 

 the summer months (Table 1). 



Laboratory procedures were the same as re- 

 ported by Perrin et al. (1976), but the analytical 

 methods differed slightly. In calculating gross 

 annual reproductive rate (proportion female x 

 proportion of total females which are reproductive 



FIGURE 1. — Sample of the offshore spot- 

 ted dolphin, Stenella attenuata, col- 

 lected in 1973-75, by 5° squares. 



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