disease in one kelp stand in southern 

 California (Schroeter and Dixon pers. 

 comm.), so this disease, like that 

 affecting sea urchins, may have important 

 community effects. The cause of the 

 disease is unknown. 



The third cause of death is 

 associated with dinoflagellate blooms (red 

 tides). Death in this case may result 



from oxygen reduction 

 dinoflagel lates decomposed. 

 (1972) stated that "fish, 

 other marine life" have been 

 particular red tides 

 California, and 

 been made at 



when the 



Fay et al . 



lobsters, and 



killed during 



in southern 



similar observations have 



least once in central 



California (Laur pers. comm.). The 

 effects of these losses on other organisms 

 in the kelp community are unknown. 



4.7.4 Vertebrates 



Fishes are affected by a number of 

 diseases, including the dinoflagellate 

 toxins above, but the widespread 

 occurrence of tumors, lesions, and fin rot 

 has been particularly common in nearshore 

 areas around large ocean sewer outfalls 

 near Los Angeles. Cross (1982) found that 

 11% of fishes caught in otter trawls in 

 this area had fin rot. However, this 

 represented a decline from previous 

 percentages, a decline coincident with the 

 reduction in chlorinated hydrocarbons, 

 heavy metals, and organic matter 

 discharged from the sewer. The incidence 



of tumors and other diseases of fishes in 

 this region is discussed by Mearns and 

 Sherwood (1977). 



Various parasites occur in kelp 

 forest fishes but the population 

 consequences of their activities remain 

 largely unknown. Some of these parasites, 

 especially certain roundworms, can be 

 harmful to man if infected fish are eaten 

 raw. Moser and Love (1978) reviewed 

 parasites of marine fish in California, 

 and suggested methods for detecting and 

 destroying those harmful to man. 



Parasites may harm fishes, but they 

 can also be used to study fish movements. 

 Some fishes with limited movements may 

 show higher incidences of a particular 

 parasite in local populations. Love 

 (1980) used such a parasite "tag" in his 

 innovative study of movements of the olive 

 rockfish (see Section 4.5 above). He 

 found that this rockfish moved little 

 between reefs; thus a particular reef can 

 be easily overfished. 



Numerous animals parasitize marine 

 mammals (see Dailey and Brownell 1971 for 

 review). The sea otter, most commonly 

 associated with kelp forests (see Section 

 4.6.6.2 above), has a number of 

 acanthocephalan parasites (Hennessy and 

 Morejohn 1977). While individual animals 

 may be seriously affected by some 

 parasites, these authors concluded that 

 effects on the sea otter population in 

 Cal ifornia are small . 



85 



