4ft000i 



UPPER NET 



MIDDLE NET 



LOWER NET 



CA LANOID COPEPO DS 



JEimi 



j_jliiii. 



2,800 



2,400 

 2,000 

 1,600 

 1,200 

 8001 

 400H 

 0^ 



\\\w\ 



I n 



0600 1200 1800 



HOUR OF DAY 



HOUR OF DAY 



HOUR OF DAY 



Figure 10, --Average number of calanoid and noncalanoid copepods per 1,000 m. of water 

 strained by the three nets on HMS-32 and 34. 



which increased from March to -July and were 

 variable thereafter. In the comprehensive 

 series the highest averages were obtained dur- 

 ing February and August on both the windward 

 and the leeward sides (see tables 4 and 7). 

 These differences are not surprising in view of 

 the high variance that characterized the means 

 for the different cruises. 



ComparisoiLS of Plankton in ^Vindward 

 and Lee^vard Samples 



The only difference in distribution of zoo- 

 plankton in windward and leeward areas was the 

 time of the winter peak--January in windward 

 and February in leeward stations (upper two 

 panels of fig. 15). The adjusted grand averages 

 for the windward and leeward areas were 22.9 

 and 20.3 cc./l,000 m,^ respectively (the dif- 

 ference was not significant). 



INSHORE-OFFSHORE SERIES 



To evaluate littoral influences on standing 

 crops of zooplankton, an inshore and offshore 

 station were designated in both the leeward and 

 windward areas off Oahu. Because regular 



sampling in the windward area was prevented 

 by unfavorable weather, data in this report are 

 limited to those from the leeward stations (sta- 

 tions 1 and 3, about 5 and 25 miles /about 8 and 

 40 kilometers^, respectively, from shore, fig. 

 15). These stations were sampled fairly regu- 

 larly by vessels of the Bureau of Commercial 

 Fisheries and by the vessel Makua of the Hawaii 

 Division of Fish and Game (table 1). All 

 samples were taken in oblique hauls with a 

 single open net at to 60 m. Some of the data 

 for this series were obtained from the compre- 

 hensive and monitor series (appendix table 14). 



The peaks in the curves showing semimonthly 

 variations of adjusted volumes for the inshore 

 and the offshore stations leeward of Oahu (fig. 

 16) coincide with those in the monitor series. 

 This is a part-whole correlation, since these 

 two stations are among the leeward and wind- 

 ward stations of the monitor series. King and 

 Hida (1954) found that zooplankton was most 

 abundant at a station 2 miles (3.2 kilometers) 

 from shore and decreased from this point in 

 both inshore and offshore directions. 



The average adjusted volumes of zooplankton 

 for the inshore and for the offshore stations 

 were identical--!?.! cc./l,000 m.*^. 



15 



