FISHERY BULLETIN: VOL. 86, NO. 4 





Figure 3.— Study site off Salmon Point. 



ing turbulence. Although all seasons were sampled, 

 most collections and observations were made when 

 the sea was relatively calm, a condition that gen- 

 erally lasted no more than a few days at a time. 

 Nevertheless, because often the weather turned 

 while observations were under way, turbulent con- 

 ditions were well represented. 



Fish 



The 5. mystinus studied at Mendocino were spa- 

 tially segregated by size and age. This paper con- 

 siders only adult fish of more than 200 mm SL, 

 which forage by day in aggregations of up to several 

 hundred individuals in the upper levels of the water 

 column. The analysis of gut-contents involved 247 

 individuals, 200-350 mm SL, taken from these ag- 

 gregations using handheld spears. Juveniles and 



subadults are excluded because they forage at lower 

 levels of the water column and consume organisms 

 not taken by adults. 



Plankton 



Most sampling sessions included two plankton 

 collections: one at the sea surface, and the other 

 between 1 and 2 m above the sea floor. Only the 27 

 surface collections are considered here, however, 

 because the others sampled at levels of the water 

 column below where adults usually feed. For each 

 collection we used scuba to push the net (0.333 mm 

 mesh in a 78 cm x 78 cm frame) through the water 

 for 5 minutes. Occasionally the net broke the sur- 

 face, but usually was kept underwater to avoid foul- 

 ing the sample with floating debris. (See Hobson and 

 Chess 1976 for additional information on this pro- 



718 



