HOBSON and CHESS: TROPHIC INTERACTIONS 



Figure 7.-A solitary kelp rockfish, 

 Sebastes atrovirens, close to rising 

 stipes of a giant kelp plant at night. 



Aoroides columbiae (15: 0.2: 0.1); Hyale nigra (5: 0.1: 0.1); 

 Ericthonias braziliensis (5: 0.2: 0.1); unidentified (40: 0.9: 

 0.8). 



4. ISOPODS (75: 3.7: 14.3) 



Paracerciefi sp. (75: 3.3: 11.8); Pentidotea resecata (5: 0.1: 

 1.8); gnathiid juveniles (10: 0.1: 0.3); Cirolana harfordi (10: 

 <0.1: 0.2); Idotea rectolinenta (5: <0.1: 0.2). 



5. POLYCHAETES, SWIMMING (20: 0.3: 7.1) 



unidentified, but only certain epitokous nereids were 

 significant, these being prominent in the guts on nights 

 when they swam in mid-water. 



6. BRACHYURAN ADULTS (10: 0.1: 4.2) 



all Pugettia prodiicta. 



7. OSTRACODS (30: 0.5: 0.9) 



Cycloleberis lobiancoi (20: 0.2: 0.5); Vargula americana (10: 

 0.2: 0.3); Parasite rope sp. A (5: 0.1: 0.1). 



8. FISHES (15: 0.1: 1.2) 



larvae (10: 0.1: 0.8); scales (5: ?: 0.4). 



9. NEBALIACEANS(5:0.1:1.1) 



Nebalia pugettensis. 



10. CUMACEANS (5: 0.3: 0.7) 



all Cgclaxpia nubila. 



11. GASTROPODS (5: 0.1: 0.1) 



Lacuna unifasciafa. 



12. EUPHAUSID ADULTS AND JUVENILES (5: 0.1: 0.1) 



unidentified. 



Xenistius californiensis—siilemz 



We never saw salema in the study area during 

 the day, but at night frequently encountered 

 solitary individuals (Figure 8), or loosely spaced 

 groups of four to six. Usually they swam high in 

 the mid-waters above the open fields of Dictyop- 

 teris within 10 m of the forest. Their first appear- 

 ance in the evening consistently occurred about 40 

 min after sunset, apparently after they had come 

 from some distance away. The relatively few 

 times we saw this species in daylight (always more 

 than 400 m from the study area), it swam in schools 

 of more than 50 individuals, closely spaced and 

 seemingly inactive, at middepths within the for- 

 est. Reportedly this fish reaches 255 mm (Miller 

 and Lea 1972).' 



Fresh material filled the stomachs of all five 

 specimens (163-180 mm, x = 170) collected for 

 study of food habits. They were taken at night, 

 more than 3 h after sunset, and before daybreak, 

 and so nocturnal feeding is apparent. All three 



Figure 8. -A solitary salema, Xenistius 

 californiensis, swims above the sea floor at 

 night. 



585 



