suitable for the Peterson method of ageing, which 

 is reproduced in Figure 4. 



The first mode centered on 7 cm total length 

 (TL) could well represent a recently recruited 

 cohort. A size of 70 mm TL corresponds to a length 

 of 58 mm SL for C. miliaris (Ralston 1975). 

 Spawning in this species is known to occur 

 between December and April but peaks around the 

 end of February or the beginning of March 

 (Ralston 1975). Consequently, about 155 days 

 elapsed between the time of peak spawning for 

 this species and the date of capture of these 476 

 specimens. Assuming growth according to Figure 

 3, after 155 days of growth, juvenile C. miliaris 

 are estimated to be 55 mm SL. This size corre- 

 sponds closely with the first mode of Wass' size- 

 frequency distribution (58 mm SL or 70 mm TL), 

 thus corroborating Figure 3. 



Further evidence in support of the von 

 Bertalanffy growth curv^e and therefore, the in- 

 terpretation of otolith ring patterns, comes from 

 examining the size at which C. miliaris first 

 reproduce. Ralston (in press) reported that both 

 male and female C. miliaris reached reproductive 

 maturity at a size of about 90 mm SL. Referring to 

 Figure 3, fish of this size are about 1 yr old. If 

 spawning is periodic, as it is in C. miliaris 

 (Ralston 1975), one expects the onset of reproduc- 

 tive maturity to occur after some multiple of the 



200-1 



180- 



• 



80- 



^ 60 



E 



3 



40- 



20- 



^^TL 



Jl 



3 4 5 6 7 8 9 10 11 12 13 14 15 

 Total Length (cm) 



Figure 4.- Size-frequency distribution of Chaetodon miliaris 

 collected by Wass (1967) in Kaneohe Bay. (Redrawn from his 

 figure 7.) 



interval between spawning periods has elapsed. 

 One year is one such interval and C. miliaris 

 becomes reproductive during the first spawning 

 season after birth. 



Evidence presented here in the form of inter- 

 pretation of the data of Wass (1967) and exami- 

 nation of age at maturity substantiate the growth 

 of C. miliaris as described by the von Bertalanffy 

 curve of Figure 3. These in turn confirm the 

 accuracy and utility of employing the diel lamellae 

 in the otoliths of fishes as growth chronometers. 

 Although a new and as yet somewhat untried 

 technique, Pannella's method of age determina- 

 tion offers the potential to age fishes in situations 

 where this was not feasible in the past. 



Acknowledgments 



This research was supported by the Hawaii 

 Cooperative Fishery Research Unit of the U.S. 

 Fish and Wildlife Service and by NOAA Oflfice of 

 Sea Grant, U.S. Department of Commerce, under 

 grant number 04-5-158-17. I thank Leighton 

 Taylor for providing the impetus to this study and 

 Paul Struhsaker for bringing Pannella's work to 

 my attention. Additional thanks are due Robert 

 MuUer, Robert Moffitt, James Uchiyama, Ivan Gill, 

 and Sharon Honda for their efforts extended in my 

 behalf. This paper is based on a portion of a thesis 

 submitted in partial fulfillment of requirements 

 for the M.S. degree at the University of Hawaii, 

 Department of Zoology. 



Literature Cited 



Allen, K. R. 



1966. A method of fitting growth curves of the von 

 Bertalanffy type to observed data. J. Fish. Res. Board Can. 

 23:163-179. 

 Beverton. R. J. H., AND S. J. Holt. 



1959. A review of the lifespans and mortality rates of fish in 

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 5:142-177. J. & A. Churchill Ltd., Lond. 

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1971. Fish otoliths: daily growth layers and periodical 

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1974. Otolith growth patterns: an aid in age determination 

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Pellegrin, D. 



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 Ralston, S. 



1975. Aspects of the age and growth, reproduction, and diet 



993 



