RALSTON AND MIYAMOTO: OTOLITH INCREMENTS OF HAWAIIAN SNAPPER 



FIGURE 3. — A scanning electron microscope (SEM) photograph of a sagitta from Pristipomoid.es filamentosus, showing radial development of 



aragonite crystals transected by incremental and discontinuous zones. 





ing captivity and did not feed for 2 d after treatment, 

 we interpret these as confirming results. During the 

 course of the experiment a 1:1 correspondence was 

 maintained between increments and days, demon- 

 strating the presence of daily marks rather than 

 features entrained to other periodicities (e.g., sub- 

 daily marks). 



Otolith Growth 



Due to the likelihood of allometric relationships, it 

 is important to distinguish between the growth of the 

 otolith and the growth of the whole fish. Figure 5 

 shows that the slope of the log- linear power function 

 regression of otolith length on fork length, based on 

 measurements from 66 individuals, is significantly 

 <1 (fi= 0.6286, t=- 14.12, df= 64). This is typical 

 of many fish species (Hickling 1933; Templeman and 

 Squires 1956; Blacker 1974; but see Taubert and Co- 

 ble 1977) and implies that the growth rate of 



opakapaka otoliths \-ti) is not related in a simple 

 linear fashion to somatic growth rate. 



TABLE 1. — The results of marginal increment counts 

 on tetracycline- and acetazolamide-marked otoliths 

 of Pristipomoides filamentosus. 



A total of 8 1 sagittae from 68 individuals were ex- 

 amined with light microscopy for presence of daily in- 

 crements. In 1 3 cases both left and right otoliths from 

 the same individual were viewed. These 81 samples 

 provided 2,957 separate estimates of otolith growth 

 rate along the postrostral growth axis. Initially the 

 data were pooled to elucidate the functional relation- 

 ship between otolith growth rate and otolith length. 

 The results are presented in Figure 6. 



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