FISHERY BLXLETIM; VOL, 69. N'O. J 



experiences conflicting responses, one moment 

 tolerating or even soliciting the cleaner's atten- 

 tions, and the next moment chasing it awaj' on 

 each approach. Such ambivalent behavior was 

 especially evident in rubberlip perch. Losey 

 (1971) noted that Labroides phthirophagus in 

 Hawaii is sometimes attacked by fishes that it 

 attempts to clean, and suggested that this may 

 occur when the cleaning is painful to the host 

 fish. 



The color changes shown by many fishes being 

 cleaned (Randall, 1958; and others) may in fact 

 be manifestations of stress. It is well known 

 that many fishes experience color changes in re- 

 sponse to stress. Earlier (Hobson, 1965a) I dis- 

 cussed the striking color change of the goatfish 

 Mulloidichthys dentatns when it solicits cleaning 

 in the Gulf of California, and pointed out that 

 this fish shows the same color change in other 

 situations that are obviously stressful. Such 

 color changes have been regarded as signals be- 

 tween the fishes being cleaned and the cleaners, 

 (e.g., Feder, 1966), functioning in the cleaning 

 interaction much like the soliciting attitudes 

 discussed above. As with the attitudes, any role 

 such color changes may now have assumed as a 

 signal probably evolved from an incidental by- 

 product of early cleaning. I have no data on this 

 point relating to the California species, as such 

 color changes are not especially evident in fishes 

 that were observed being cleaned there. 



ARE CLEANERS IMMUNE FROM 

 PREDATION.' 



Reportedly some cleaners are immune from 

 pi'edation because of the service they provide 

 the predators (Feder, 1966; and others). Lim- 

 baugh's (1961) belief that the senorita enjoys 

 such immunity is based on observations of this 

 labrid entering the open mouth of kelp bass to 

 clean and on not finding it among the stomach 

 contents of predators during a food-habit study. 

 However, Quast (1968) found seiioritas in the 

 stomachs of kelp bass, and H. Geoffrey Moser, 

 U.S. National Marine Fisheries Service (unpub- 

 lished data), found sefioritas in stomachs of the 

 bocaccio, Sebastes paucispinis, and the starry 

 rockfish, S. constellatiis. 



I doubt that cleaners enjoy immunity in 

 the sense that predators, recognizing them as 

 benefactors, actively avoid preying on them. 

 Cleaners may recognize those predators which 

 are not at that time intent on feeding and may re- 

 strict their cleaning to such individuals. A preda- 

 tor that assumes a soliciting posture may effec- 

 tively advertise this situation, and no doubt other 

 cues exist. Such mechanisms would reduce the 

 chance of cleaners placing themselves in vulner- 

 able situations while cleaning. In addition, clean- 

 ers probably are not as vulnerable while cleaning 

 large predators as might be expected simply be- 

 cause cues characteristic of feeding situations 

 are not present. In associating themselves so 

 intimately with predators, cleaning fishes show 

 behavior that is so unlike that of prey that preda- 

 tors probably do not regard them as food. How- 

 ever, even if such factors do reduce the danger 

 that might seem inherent in the cleaning act, 

 I doubt that their cleaning role affords these 

 fishes any security from being eaten in non- 

 cleaning situations. 



PARASITES AS PREY OF THE 

 CALIFORNIA CLEANERS 



It is hardly surprising that the fishes which 

 are cleaned most frequently in California are 

 those which are the most abundant and at the 

 same time carry the most ectoparasites. Thus 

 the blacksmith, topsmelt, halfmoon, and gari- 

 baldi are the fishes cleaned most frequently, 

 and the survey of ectoparasites showed them to 

 be among the most heavily parasitized. The 

 vast majority of ectoparasites on these particular 

 fishes are mobile forms, mostly caligid copepods 

 and gnathiid isopod larvae, that occur on the 

 body surface of their hosts. That these same 

 parasites were found to make up the diet of the 

 cleaners attending these fishes is consistent with 

 the observation that only the exteriors of fishes 

 were seen being cleaned during this study. 



Although the forms infesting the external 

 body surface are the most numerous ectopara- 

 sites on the fishes available to the California 

 cleaners, many other types were found to infest 

 the oral and branchial cavities. One might ques- 

 tion why these other parasites do not seem to be 



518 



