HOAG: SUMMER FOOD OF JUVENILE SOCKEYE SALMON 



(P = 0.05) in the percentage of Cyclops and 

 Bosmina in fry foreg-uts, yearling foreguts, and 

 zooplankton hauls in late summer 1967. The 

 percentage of calanoid copepods in fry and year- 

 ling foreguts did not differ significantly, but both 

 differed significantly from that in the zooplank- 

 ton hauls. 



Spatial and temporal changes in the composi- 

 tion of the zooplankton catches were compared 

 with changes in the fish foreguts. In the zoo- 

 plankton hauls, the percentage of Cyclops gen- 

 erally decreased and the percentage of Bosmina 

 generally increased from early to late summer 

 and from area IV to area I. The composition 



Table 3. — Mean percentages of Cyclops, Bosmina, and calanoid copepods in the foregut of fry and yearlings 

 (insects excluded) and in the zooplankton samples by area and sampling period. 



Table 4. — Mean squares and degrees of freedom for a "two-way crossed" analysis of variance by sampling pe- 

 riod and zooplankton. 



F test significant a\ P = 0.05. 

 F test significant ai P = 0.01. 



359 



