Predators feeding on large, mobile 

 prey in the canopy-midwater regions 

 include the giant kelpfish ( Heterostichus 

 rostratus ) , the kelp bass ( Paralabrax 

 clathratus ) , the kelp rockfish ( Sebastes 

 the olive rockffsh (S. 

 and the black rockfish (_S. 

 Young olive rockfish eat 



atrovirens ) , 



serranoides ] 



melanops ) . 



plankton (Hobson and Chess 1976, Love and 



Ebeling 1978). 



The cryptically-colored giant 

 kelpfish occurs throughout the 

 water-column in close association with 

 Macrocystis and other seaweeds. Although 

 rarely seen in central California, it is 

 particularly common in kelp forests around 

 islands off southern California. The 

 giant kelpfish feeds during the day in 

 open water, on substratum-oriented prey 

 such as mysids, isopods, amphipods, shrimp 

 and fish (Coyer 1979, Hobson et al . 1981). 



The kelp bass (Figure 22) was 

 described by Quast (1968, 1971a) as a 

 medium-sized, generalized carnivore 

 occupying a wide variety of environments. 

 Kelp bass tend to move only slightly among 

 reefs (Young 1963) and will congregate at 

 heavily fished and chummed sites. Food 

 habits change with age; juveniles (< 299 

 mm) eat primarily benthic invertebrates 

 and plankton, but switch to fish when they 

 grow larger (Love and Ebeling 1978, Hobson 

 et al. 1981). Kelp bass over 30 cm eat 

 predominately fish, although invertebrates 

 occasionally are found in their stomachs. 

 In southern California, kelp bass are 

 regarded as one of the primary fish 

 predators in the kelp forest. This 

 species is not as common in central 

 Cal ifornia. 



The kelp rockfish (Figure 22), a 

 common cryptic species, can be found 

 throughout the water column associated 

 with kelp. Kelp rockfish hover adjacent 

 to kelp stipes, during the day and night 

 in central California, but both rest on 

 the bottom and hover at night in southern 

 California (Hobson and Chess 1976, Van 

 Dykhuizen 1983). They feed on a wide size 

 range of prey items, including plankton, 

 epibenthic invertebrates, and juvenile 

 fishes. Kelp rockfish feed primarily at 

 dawn and at night, but will take prey 

 whenever it is abundant. 



The olive rockfish (Figure 22), 

 common to both central and southern 

 California kelp forests, is a large 

 midwater predator. Unlike kelp bass, 

 which they superficially resemble, adult 

 olive rockfish generally remain in the 

 same location on a particular reef (Love 

 1980). Juveniles, subadults, and adults 

 differ in their feeding behavior (Hobson 

 and Chess 1976, Love and Ebeling 1978, 

 Love and Westphal 1981). Juvenile olive 

 rockfish < 55 mm form aggregations in the 

 water column, and feed on copepods, 

 amphipods and larvae. Intermediate-sized 

 juveniles, 55-65 mm, feed day and night on 

 amphipods, cumaceans, and mysids. Large 

 juveniles (> 65 mm) are active at night, 

 hovering in midwater aggregations over the 

 bottom, and feeding on amphipods, mysids, 

 and other crustaceans. Adults may feed 

 day or night on juvenile fishes, octopus, 

 and squid. The local distribution and 

 food habits of the olive rockfish in 

 central California are similar to those of 

 the kelp bass in southern California (see 

 discussion in Love and Westphal 1981). 



Black rockfish are rare in southern 

 California kelp forests, but common in 

 central California. This species occupies 

 the midwater zone, solitary or 

 interspersed with schools of blue 

 rockfish. Juvenile rockfish are important 

 prey for the black rockfish during the 

 upwelling period (spring-early summer), 

 while polychaetes are important prey at 

 other times of the year (Roberts 1979). 



Kelp forest fishes that feed 

 predominantly on plankton include blue 

 rockfish ( Sebastes mystinus ) , the 

 blacksmith ( Chromis punctipinnus ) , and 

 juvenile rockfishes ( Sebastes spp. ) . Blue 

 rockfish (Figure 22) are the most common 

 rockfish in the kelp forests of central 

 and southern California. They occupy the 

 open-water habitat in kelp forests or over 

 deep, rocky reefs devoid of kelp. 

 Individuals of this species occur alone, 

 in loose schools, or in large aggregations 

 (Miller and Geibel 1973). Blue rockfish 

 are also one of the most important sport 

 species in central and northern California 

 (Miller and Geibel 1973). The habitats of 

 the blue rockfish in central California 

 are similar to those of the blacksmith 

 (see below) in southern California. The 

 feeding habits of the blue rockfish differ 



72 



