FOOD, ACTIVITY, AND HABITAT OF THREE "PICKER-TYPE" 



MICROCARNIVOROUS FISHES IN THE KELP FORESTS OFF 



SANTA BARBARA, CALIFORNIA 



Richard N. Bray and Alfred W. Ebeling' 



ABSTRACT 



Diets, daily activity, and habitat preference were compared between the kelp perch, Brachyistius 

 frenatus; the senorita, Oxyjulifi californica; and the white seaperch, Phanerodon furcatus, all of which 

 co-occur in areas of reef and kelp off Santa Barbara, Calif. The kelp perch and senorita often clean 

 ectoparasites off larger host fishes, whereas the white seaperch is a more generalized picker-type 

 microcarnivore. 



The kelp perch and senorita, which co-occur in the kelp canopy, showed the least amount of total 

 overlap in resource use, expressed as a combination of individual overlaps in food, activity, and habitat. 

 The senorita had the narrowest breadth of diet but the widest breadth of habitat (within the kelp-bed 

 areas). Senoritas and white seaperch ate mostly bryozoans encrusted on plants, whereas kelp perch ate 

 mostly plankton and other tiny motile prey. As species, neither the kelp perch nor the senorita derives 

 substantial amounts of food from cleaning, although some individual senoritas may. Unlike the two 

 "cleaners," the white seaperch also ate substantial numbers of bottom prey. None of the species forage 

 at night, when all are relatively inactive, and when the senorita actually buries itself in patches of 

 rubble and sand on the reef. The two perches showed the greatest overlap in daytime activity, as 

 measured both by bi-hourly counts of feeding bites in the field and of swimming movements in a 

 laboratory tank. 



Fishes that exploit the same class of environmen- 

 tal resources in similar ways may be thought of as 

 forming a "guild" of species having similar 

 ecological roles regardless of their taxonomic 

 affinities (Root 1967). In and about the forests of 

 giant kelp off southern California, fishes that can 

 select relatively small prey from mid-water and 

 from kelp or other surfaces form a foraging guild 

 of "pickers" (cf. Hobson 1971). Hubbs and Hubbs 

 (1954) stressed the fact that two common and 

 taxonomically unrelated pickers have remarkably 

 similar mouth structures and dentitions: the kelp 

 perch, Brachyistius frenatus, which is in the 

 primarily temperate family of surfperches Em- 

 biotocidae, has evolved the same general type of 

 pointed snout, tiny jaws, and protruding canines 

 that characterize the senorita, Oxyjidis califor- 

 nica, and most other members of the primarily 

 tropical family of wrasses Labridae. 



Hobson (1971) noted that the habit of cleaning 

 ectoparasites off larger fishes is widespread 



'Marine Science Institute and Department of Biological 

 Sciences, University of California, Santa Barbara, CA 93106. 



Manuscript accepted January 1974. 

 FISHERY BULLETIN: VOL. 73, NO. 4, 1975. 



among the picker-type fishes. Senoritas, kelp 

 perch, and young of another embiotocid, the 

 sharpnose seaperch, Phanerodon atripes, are the 

 most consistent "cleaner fishes" of the kelp beds 

 (Limbaugh 1961; Hobson 1971). Compared to some 

 small tropical wrasses (Randall 1958), however, 

 these species are less specialized as cleaners: their 

 cleaning activities are sporadic and/or confined to 

 certain individuals, and so their principal forage 

 must be elsewhere (Hobson 1971). 



With this in mind, we compared the diets, daily 

 activity patterns, and habitat preferences of the 

 senorita and kelp perch, which are the principal 

 cleaner fishes in the Santa Barbara area, with 

 those of a more generalized picker, the white 

 seaperch, P. furcatus. These three species have 

 been studied off San Diego (Limbaugh 1955; Quast 

 1968a, b; Hobson 1971). Yet little has been 

 published on their habits and distribution off 

 Santa Barbara. Here the Channel Islands and the 

 east-west oriented coastline protect kelp beds 

 from swells, enabling giant kelp to anchor on low- 

 relief and soft bottoms as well as to high-relief 

 reefs. Also, species with centers of distribution 

 located far to the north are more frequently en- 

 countered (Quast 1968a; Ebeling et al. 1971). 



815 



