FISHERY BULLETIN: VOL. 74, NO. 1 



Table 2. — The mean and median biomass (grams dry weight per 10 m^) for micronekton and macro- 

 plankton during summer (S = May-October) and winter (W = November- April) at five stations (28, 

 46, 84, 120 and >120 km) off the Oregon Coast. Probabilities resulting from Mann- Whitney U and t 

 tests of seasonal differences are given. 



and 120 km using the non-parametric Mann- 

 Whitney U test (Tate and Clelland 1957 ) and at 46, 

 84, and 120 km using the parametric t test. Mann- 

 Whitney U tests for the three taxa of micronekton 

 indicated significant seasonal differences for 

 standing stocks of fishes at 46, 84, and 120 km, 

 for shrimps at 46 km and for squids at 84 km. 



Macrozooplankton 



Values for the biomass of macrozooplankton 

 collected at four stations during 1963-67 are 

 shown in Figure 5 and Table 3. Inshore-offshore 

 and seasonal trends are less apparent than for 

 micronekton. The total MN biomass per 10 m^ is 

 lowest at the 28-km stations, greater at the 

 120-km stations, and highest at the 46-, 84-, and 

 120-km stations (Table 3). 



Of the taxonomic groups composing the MN 

 samples, copepods were most important on an 

 average dry weight basis at all stations except at 

 46 km where euphausiids were very abundant 

 (Table 3). The standing stock of medusae ranked 

 second after copepods at all stations except at 46 

 km where it ranked third after copepods. Even 

 though the maximum biomass of all groups oc- 

 curred at 46, 84, or 120 km on a square meter 

 basis, the maximum weights of copepods and 



Table 3. — Biomass of zooplankton per 10 m^ collected with 

 1-m diameter nets at the stations off Newport, Oreg. 



medusae on a cubic meter basis were found at 28 

 km, nearest the coast. 



Differences in the biomass of macrozooplankton 

 between the two seasons were only significant at 

 one station, 84 km offshore (Table 2), although 

 distinct peaks occurred during the summers of 2 yr 

 at 120 km (Figure 5). Surprisingly, most of the 

 taxonomic groups of zooplankton, including 

 copepods and euphausiids, evidenced no seasonal 

 changes at any stations. The only significant 



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