LOVE and EBELING: FOOD AND HABITAT OF THREE FISHES 



SEASON 

 MAR-MAY JUN-AU8 

 (13) (8) 



BLUE 

 RKF. 



KELP 

 BASS 



OLIVE 



RKF. 



(NAPLES) 



P S 

 N §21% 



S 



K 



Jll% |jl8% 

 (7) (35) 



79% 



36% 



0.025 >P 

 >QOI 



0.05) P 

 > 0.025 



Figure 2. — Seasonal variation in percentage frequency of prey 

 tjfpes (bars and numbers) in stomachs of fish in the 151- to 

 300-mm SL size group (Table 1) of the three species of kelp-bed 

 fishes from Naples Reef (all three species) or One-Mile Reef (olive 

 rockfish only) off Santa Barbara, Calif. Prey types (P-K) are 

 designated in Figure 1; seasonal periods are explained in the 

 text; and numbers in parenthesis aire numbers of fish stomachs 

 examined. Hatching shows significant seasonal differences at 

 the indicated probabilities determined by chi-square tests (see 

 text). 



containing mostly nekton averaged fuller (weigh- 

 ted means pooled among seasons = 3.12-3.48) than 

 stomachs containing mostly other prey (2.14- 

 2.67). 



Table 7. — Numbers of the three species of kelp-bed fishes 

 (excluding small juveniles) observed in movie strips (cinetran- 

 secta) taken at Naples Reef or Santa Cruz Island study sites off 

 Santa Barbara, Calif Cinetransects are classified as taken 

 either in and about the kelp canopy or reef bottom (see text). 



Naples Reef Santa Cruz Island 



Cinetransect samples: CInetransect samples: 



canopy = 129, bottom = 168 canopy = 146, bottom = 185 



Species 



Total No. in % in 

 fish canopy canopy 

 observed samples samples 



Total No. in % in 

 fisfi canopy canopy 

 observed samples samples 



Habitat 



Blue rockfish 3,305 2.953 89.3 919 636 69.2 



Kelp bass 861 324 37.6 1,065 318 29.9 



Olive rockfish 140 119 85.0 922 843 91.4 



ing clear-water days over Naples Reef. Blue rock- 

 fish often mingle with blacksmith, a specialized 

 daytime planktivore with small mouth and com- 

 pressed body. Blacksmith are quicker and more 

 maneuverable than blue rockfish, which pick 

 plankton more slowly and seem to have more 

 difficulty repositioning themselves after feeding 

 lunges. Small numbers of kelp bass and olive 

 rockfish occasionally join the plankton pickers and 

 feed at even lower rates. Although all plankton 

 pickers may cooccur in the same field of view, they 

 usually segregate by species. Larger individuals 

 are usually lower in the water column. But even 

 big kelp bass occasionally pick small particles 

 from near the surface. 



All three species were more numerous over 

 greater bottom depths (to about 12 m), where the 

 reef-fish community is generally richer and more 

 abundant (Table 8). Kelp bass and olive rockfish 

 tended toward zones of greater underwater visibil- 

 ity and kelp density, with kelp bass often prefer- 

 ring the outer margin of the kelp bed. Both 

 rockfishes occurred in greater numbers over 

 high-relief rocky bottoms. Olive rockfish 

 (juveniles and subadults) were more numerous 

 higher in the water column. 



The three species occurred throughout the 

 water column. However, most rockfish (juveniles 

 and subadults) were recorded in canopy cinetran- 

 sects (Table 7), and younger blue rockfish (reddish 

 phase) usually clustered near the bottom close to 

 shelter. In contrast, kelp bass were more abun- 

 dant in bottom transects (Table 7). Relatively 

 more blue rockfish and kelp bass were recorded in 

 canopy transects over Naples Reef, where bottom 

 and canopy tend to merge along the reef crest. 



One of us (Ebeling) has observed small- to 

 medium-sized fish (ca. 100-250 mm SL) feeding 

 together between middepth and kelp canopy dur- 



Table 8. — Correlations between numbers of the three species of 

 kelp-bed fishes and environmental variables observed in an ini- 

 tial set of 175 movie strips (cinetransects) taken over a variety of 

 locations and subtidal habitats along ca. 24-km stretches of 

 coastline at the mainland and Santa Cruz Island off Santa Bar- 

 bara, Cfdif. Numbers are Kendall's tau coefficients of rank corre- 

 lation, significant at P«0.05. 



265 



