FISHERY BULLETIN; VOL. 74, NO. 1 



preponderance of small, adult copepods represent- 

 ing two genera. Larvae less than 20 mm fed 

 exclusively during day, at 20 mm they began 

 occasional feeding at night, and when they at- 

 tained a length of 25 mm they fed regularly at 

 night. None of these changes in feeding habits 

 seem related to the 15-17 mm inflection. 



Only one fish, estimated to be 189 days old at a 

 length of about 63 mm, indicated that the Kane- 

 ohe Bay population of nehu may enter an asymp- 

 totic growth phase at about 60 mm. Obviously, 

 additional collections of older fishes are required 

 to elucidate this portion of the growth curve. 



The absence of large adults might be explained 

 by the heavy exploitation of this stock by commer- 

 cial fishermen. Another possible explanation re- 

 lates to the observations of Muller^ on Stole- 

 phorus heterolobus Riippell in the Palau Islands of 

 the western Pacific. He found that large spawning 

 adults occur in open lagoon waters 2-4 km offshore 

 over depths of 30-40 m during night. The daytime 

 distribution of these individuals is unknown, but 

 it is thought that they occur near bottom in the 

 open lagoon. In the case of nehu, however, the 

 explanation of an absence of adults in the asymp- 

 totic growth phase by invoking an offshore spawn- 

 ing movement is argued against by a recent study 

 demonstrating that this species is capable of 

 spawning at a length of 35-40 mm (Leary et al. in 



press). 



These readings of whole-mounted sagittae from 

 Kaneohe Bay nehu did not reveal any periodic 

 deposition patterns of increments or spawning 

 checks as reported by Pannella (1971). 



Geographical Comparison 

 of Growth Rates 



One of the more exciting aspects of being able to 

 accurately determine growth rates of young fishes 

 is the tool that it provides to examine the effects of 

 various environmental conditions. As an exercise, 

 we compared the linear segments of the growth 

 curves of two samples {n = 15) of nehu collected 

 during March and April 1972 in Pearl Harbor and 

 Kaneohe Bay (Figure 7). Unfortunately, the dif- 

 ferences in size ranges of the two samples and the 

 small sample sizes resulted in significant hetero- 

 geneity of variance (P <0.05). The analysis of co- 

 variance did indicate, however, that there may be 



140 

 130 

 120 



no 



;;; '°° 



UJ 



< 80 



70 

 60 

 50 

 40 



KANEOHE BAY 



PEARL HARBOR 



^MuUer, R. G. Population biology of Stolephorus heterolobus 

 Riippell in Palau. Ph.D. Dissertation in preparation. University 

 of Hawaii, Honolulu, HI 96822. 



-JJ ^ 28 30 32 34 36 38 40 ^ 44 46 48 50 52 54 

 STANDARD LENGTH (men) 



FIGURE 7.— Comparison of Stolephorus purpureas growth rates 

 in Pearl Harbor and Kaneohe Bay, spring 1972. 



significant differences between the regression co- 

 efficients (P <0.05) and elevations (P <0.01) of 

 the two population curves, the Pearl Harbor sam- 

 ple exhibiting a faster growth rate to a length of 

 about 44 mm. Similar, but more intensive, studies 

 should provide a wealth of insight into a variety of 

 aquatic situations. 



ACKNOWLEDGMENTS 



We are indebted to Denis C. K. Pang, Barbara 

 Sumida, and Kenneth M. Hatayama for furnish- 

 ing us with specimens of nehu from Kaneohe Bay. 

 Supplementary increment counts were accomp- 

 lished by Patricia L. Seidl and Glen H. Sugiyama. 

 We thank Paul M. Shiota for assistance in con- 

 ducting the experiments. Illustrations are by 

 Tamotsu Nakata. 



LITERATURE CITED 



BROTHERS, E. B., C. P. MATHEWS, AND R. LASKER. 



1976. Daily growth increments in otoliths from larval and 

 adult fishes. Fish. Bull., U.S. 74:1-8. 

 BURDICK, J. E. 



1969. The feeding habits of nehu iHawaiian anchovy) 

 larvae. M.S. Thesis, Univ. Hawaii, Honolulu, 54 p. 

 DEGENS, E. T, W. G. DEUSER, AND R. L. HAEDRICH. 



1969. Molecular structure and composition offish otoliths. 

 Mar Biol. (Berl.) 2:105-113. 



Leary, D. F, G. I. Murphy, and M. Miller. 



In press. Fecundity and length at first spawning of the 

 Hawaiian anchovy, or nehu (Stolephorus purpureas 

 Fowler) in Kaneohe Bay, Oahu. Pac. Sci. 



Messieh, S. N. 



1972. Use of otoliths in identifying herring stocks in the 



southern Gulf of St. Lawrence and adjacent waters. J. 



Fish. Res. Board Can. 29:1113-1118. 

 NAKAMURA, E. L. 



1970. Synopsis of biological data on Hawaiian species of 

 Stolephorus. In J. C. Marr (editor), The Kuroshio: A sym- 



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