MAYNARD ET AL.: HAWAIIAN MESOPELAGIC MICRONEKTON 



We searched the literature for data to compare the 

 standing stock and composition of micronekton 

 off Hawaii with that of other regions. Few studies 

 provided data from more than one sampling 

 period; each used different gear and techniques, 

 and all are subject to most of the restrictions cited 

 previously. We feel that meaningful regional 

 comparisons are premature until data on the tem- 

 poral variability of the fauna are available from 

 samples covering the entire depth range of the 

 fauna. 



Diel Vertical Migration 



About one-half of the total micronekton wet- 

 weight biomass in our study area appeared to 

 migrate from day-depths greater than 400 m to 

 night-depths shallower than 400 m. During the 

 day, about 90% of the mean total micronekton 

 standing stock biomass lived deeper than 400 m 

 (Tables 5, 7). Because most vertically migrating 

 fishes have a lower water content than non- 

 migrators (Childress and Nygaard 1973) the per- 

 cent of total micronekton dry weight which 

 migrates would be even higher. The same probably 

 holds for cephalopods. If migrators have shorter 

 life spans and higher metabolic rates than non- 

 migrators (cf. Childress and Nygaard 1973; T. A. 

 Clarke 1973; Meek and Childress 1973), then the 

 percent of the annual micronekton production 

 represented by migrating animals would be 

 especially high. 



ACKNOWLEDGMENTS 



This study would have been impossible without 

 the help of many friends, whom we are happy to 

 acknowledge. We are especially grateful to 

 Richard E. Young who has provided guidance and 

 inspiration throughout the project. T. A. Clarke, T. 

 K. Newbury, and V. L. Ridge read the manuscript 

 and made valuable critiques; we appreciate their 

 efforts. E. M. Kampa graciously supplied her un- 

 published irradiance data for our use. S. S. Ames- 

 bury helped us process the fishes. We also extend 

 our mahalo to Red Scholtz and his crew of the late 

 RV Teritii for their able seamanship. This project 

 was supported in part by NSF grant GA-33659, 

 funds from the University of Hawaii Department 

 of Oceanography, and by the Hawaii Community 

 Scholarship Program. 



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