FISHERY BULLETIN: VOL. 73, NO. 4 



Forage on attached organisms was less impor- 

 tant. Cheilostomate bryozoans, principally 

 Membra nipora ("plant-encrusting bryozoans"), 

 ranked a distant third in overall volume. 

 Memhranipora is the dominant bryozoan encrust- 

 ing kelp, where it often covers large areas of the 

 plant (Woollacott and North 1971), and most of the 

 bryozoans in the gut contents were associated 

 with bits of kelp blades. Kelp perch apparently ate 

 no benthic prey. 



Cleaning activity was but a minor food source. 

 Parasitic copepods, gnathiid isopod larvae, and 

 fish scales were the only items likely to have been 

 ingested in the process. The combined items never 

 contributed more than 5% to the foregut food 

 volume in a single fish. 



White Seaperch 



Virtually all prey of the white seaperch were 

 substrate oriented, probably picked from off the 

 kelp or bottom (Table 2). Plant-encrusting 

 bryozoans predominated, and when present, 

 averaged 85% of the foregut contents of individual 

 fish. Moving prey, primarily amphipods and 

 shrimps, were much less important. Many of the 

 gammarid amphipods were quite small (<2 mm 

 long); in one fish, e.g., all of 70 individuals did not 

 fill the foregut. 



Only the white seaperch ingested appreciable 

 amounts of bottom items. Crushed shells and sand 

 particles, which often were cemented into tubes, 

 ranked second in overall abundance and third in 

 frequency. The remains of polychaete worms were 

 found in but 3 of 14 sand-containing guts, which 

 did, however, include substantial numbers of the 

 gammarids that commonly inhabit such burrows 

 in the tufted mat on the bottom. Relatively large 

 amounts of loose sand in the mid- and hindguts 

 indicated that these fish generally do not winnow 

 non-food items in their mouth. 



Senorita 



Most of its prey was substrate oriented, proba- 

 bly picked from off the kelp (Table 2). Like white 

 seaperch, senoritas contained a predominance of 

 plant-encrusting bryozoans, but unlike perch, had 

 almost no bottom prey in the foregut. A third of all 

 fish examined contained only the bryozoan 

 Memhranipora encrusted on pieces of kelp, and 

 bits of bare plant material were found frequently 

 among the encrusted pieces; of a total of 18 



categories of food items found in senorita guts, no 

 other so dominated the contents of even a single 

 fish. Hydroids, another item attached to plants and 

 other substrates, ranked third in overall impor- 

 tance. Moving prey, primarily amphipods, were 

 less important. 



Unlike kelp perch, senoritas did not exploit 

 plankton as a major source of food. Although some 

 items occurred frequently, they contributed but 

 little to the overall volume. 



Cleaning activity did not produce substantial 

 forage, although it contributed relatively more to 

 the diet of senoritas than to that of kelp perch. Of 

 10 adult senoritas, 142-184 mm long, that con- 

 tained items likely to have been ingested during 

 cleaning (parasitic copepods, gnathiid isopod lar- 

 vae, and/or fish scales), the diets of seven were 

 dominated by other food items. Ectoparasites and 

 scales in guts of most senoritas were mixed with 

 other food items, suggesting that the fish had both 

 cleaned and foraged during the same day. 

 However, guts of two of the remaining three fish 

 contained nothing but parasitic copepods and 

 scales. One specimen, collected at 1400 h, contained 

 465 fish scales, about 90% of the total contents, and 

 45 parasitic copepods. Both items were distributed 

 more or less evenly throughout the length of the 

 gut, indicating that this fish had cleaned during 

 most of the day. 



Diel Forage 



All three species fed mostly, if not exclusively, 

 during the day. Foreguts of kelp perch apparently 

 were beginning to fill soon after dawn, were 

 generally full by midmorning, and contained 

 variable amounts of food through dusk (Figure 1). 

 Of 54 day and 38 late-night (midnight-dawn) 

 foreguts examined, 89% and 13%, respectively, 

 contained food. Guts of white seaperch seemed to 

 reach maximum fullness during midmorning and 

 late afternoon. Of 64 day and 22 late-night 

 foreguts examined, 88% and 4%, respectively, con- 

 tained food. Fullness of mid- and hindguts of both 

 species generally substantiated this daily cycle of 

 feeding (Figure 2). Most foreguts were empty by 

 midnight, when midguts still averaged at least 

 half full and hindguts usually more. Then, by dawn 

 most hindguts were empty, while foreguts were 

 beginning to fill, a general pattern shown by fish 

 whether collected during moonlit or dark nights. 

 Senoritas seemed to feed actively through early 

 afternoon, showing maximum gut fullness about 



820 



