Sea bird and pinniped rookeries on the Channel Islands . Sea birds nest 

 and roost on the Channel Islands and feed in near shore waters. Certainly, 

 the risk is high that birds would become contaminated if oil entered near 

 shore waters. Although improvements have been made in bird cleaning and re- 

 habilitation techniques (International Bird Rescue Research Center 1978), 

 survival rates of oiled birds are still very low. 



The Channel Islands are also used by several pinniped species as haul-out 

 areas or rookeries. San Miguel Island (Figure 1), the western-most island and 

 closest one to the cool California current, is used as a haul-out area by six 

 pinniped species, five of those species breed there. For two of them 

 (Steller's sea lion, northern fur seal) San Miguel Island represents the 

 southern-most extension of the breeding range. 



The effects of oil on pinnipeds are incompletely known. Mortalities of 

 elephant seal pups oiled during the 1969 Santa Barbara spill were no greater 

 than for unoiled pups (LeBoeuf 1971). Experimental work with ringed seals 

 showed that exposure to oil caused reversible eye damage in healthy animals. 

 However, animals already showing physiological signs of stress died soon 

 after exposure (Engelhardt et al. 1977). Animals that partially depend on 

 their pelts for insulation (e.g., northern fur seal) could suffer from ex- 

 posure (particularly in cold waters) if oil were to interfere with the insu- 

 lating properties of the pelt. Some marine mammal specialists have speculated 

 that oil effects would be most profound during the pupping season when pups 

 not only become oil coated, but ingest oil from their contaminated mothers 

 (LeBoeuf 1971). Recent observations in the North Sea indicate that normal 

 oil-avoidance behavior may be suppressed during the breeding season (Cowell 

 1979). 



Although oil effects on pinnipeds may be incompletely known, some inter- 

 esting observations have been made on the effects of disturbance by humans. 

 The National Marine Fisheries Service has conducted marine mammal tagging and 

 capture operations on the Channel Islands. It found that animals did not re- 

 occupy disturbed beaches for from one to several days after such disturbances 

 (Beach 1976, personal communication). If the disturbance occurred during the 

 breeding season while males were holding territory, the whole social structure 

 of the herd could be changed by a single disturbance (DeLong 1975). 



Clearly, the best strategy to protect sea bird and pinniped rookeries on 

 the Channel Islands is to prevent oil from reaching near shore waters around 

 these islands. This is an instance where the use of chemical dispersants in 

 the open sea should be considered. Mechanical means of oil containment and 

 retrieval are not likely to be completely effective, particularly in heavy 

 seas. For example, if a slick is headed for the west end of San Miguel 

 Island, it could be dispersed chemically in the open sea (at a distance of 

 greater than 5 miles from the island). This might prevent impacts on birds 

 and mammals from oil and disturbance from cleanup or other near shore spill 

 related activities. If oil does reach rookery beaches, cleanup is not 

 recommended. Near shore activities of any type should be kept to a minimum. 



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