FISHERY BULLETIN: VOL. 74, NO. 4 



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Figure l.-Scored fullness (1, empty-5, full) of foreguts of five 

 demersal surfperches: a, Embiotoca jacksoni; b, E. lateralis; c, 

 Hypsurus caryi; d, Damalichthys vacca; and e, Rhacochilus 

 toxotes. Each point represents the median score and each vertical 

 line the range of scores for (n) individuals collected over a 2-h 

 interval. Time is measured relative to sunrise (0600 h) and sunset 

 (1800 h). 



le). Some 67% of the fish collected at night con- 

 tained food in their foreguts, and 49% of those 

 collected during the day also contained food, 



Table 5.- Day-night variation in "foregut" emptiness for the 

 five species of demersal surfperches. Values of chi-square with 1 

 df were calculated from day-night, empty-not empty values in 

 contingency tables for each species. 



although this difference was not significant (Table 

 5). 



It is likely that many of the large-mouthed 

 demersal species feed any time that suitable prey 

 are available. Included among these species are 

 various rockfishes {Sebastes carnatus, S. chry- 

 somelas, and S. serriceps) and Scorpaenichthys 

 marmoratus, all of which are cryptically patterned 

 and probably ambush much of their prey. Analyses 

 of gut fullness and states of digestion relative to 

 time of day may be of little value in determining 

 the feeding chronology of these fishes, especially 

 larger individuals. Kariya (1969) showed that food 

 items may take days rather than hours to pass 

 through the stomach of Sebastes: inermis, a species 

 from Japan; and Larson (pers. commun.) found 

 that small majid crabs (10 mm carapace width) 

 were still intact in the stomachs of adults of S. 

 carnatus up to 10 h after ingestion. However, 

 other lines of evidence indicate that they feed at 

 night. We saw more individuals of 5. carnatus and 

 S. chrysomelas at night, probably because they 

 were more active then, and the types of food items 

 included in their diets suggest they feed at night 

 as well as during the day. Their diets include 

 medium-sized crustaceans (crabs, shrimps, etc.) 

 and cephalopods (Quast 1968b; Larson 1972); both 

 prey were far more active and exposed along the 

 transect line at night. We have observed in- 

 dividuals of S. carnatus and 5. chrysomelas at 

 night with live, struggling crabs and octopi pro- 

 truding from their mouths. Also, individuals of 

 these species often consumed small fishes that 

 escaped from our collecting spears during night 

 dives. Finally, all of these fishes can be caught by 

 hook and line at night as well as during the day 

 (Milton Love, pers. commun.). 



Along the transect line during the day, fishes 

 congregate in mid-water to pick plankton and 

 browse on kelp surfaces. At night, on the other 

 hand, almost all of the foraging by fishes occurs on 



710 



