341 



feeding in the aquarium the seal returned to normal health (Personal com- 

 munication by C. Brosseau to K. W. Kenyon, 1971). 



No harbor seals were observed with oil on their bodies during a 1965 to 1971 

 study of a colony on Gertrude Island in Pugent Sound (Personal communication 

 to K. W. Keynon from T. C. Newby, 1971). 



The conclusions indicated from these harbor seal observations are like those 

 for fur seals : ( 1 ) oil covering the body may interfere with normal habits and 

 lead to starvation ; (2) petroleum materials do not permanently damage the seal 

 if carefully removed; (3) in an observed colony no seals with oil were found 

 either because of no contact with oil or failure to survive such contact. 



LeBoeuf (1971) described the results of a study of the norihem Elephant 

 seals {Mirounga angustirostris) on San Miguel Island, California, made in 

 March 1969, shortly after the Santa Barbara oil spill. On 25 March 1969, his 

 group tagged 58 weaned pups and 5 yearlings that had at least 75 percent of 

 their bodies covered with a mixture of oil, mud, and sand. As a control, they 

 also tagged on the same day an equal number of clean pups on an adjacent 

 beach that was free of oil. In a period of 1 to 15 months after the animals were 

 marked, a total of 25 (40 percent) of the animals that were oiled were sighted 

 in apparent good health and 15 (25 percent) of the control group were reported. 

 LeBoeuf (1971, p. 280) concluded that: "These data supix>rt the conclusion that 

 the crude oil which coated many weaned elephant seals at San Miguel in March 

 and April 1969, had no significant immediate nor long-term (1-15 months later) 

 deleterious effects on their health. Had the rookery been contaminated earlier 

 in the season when females were nursing, pups might have ingested the crude 

 oil and more serious consequences might have ensued." Studies of tissues from 

 dead marine mammals found on San Miguel Island after the oil spill failed to show 

 anv evidence that they might have died because of oil ( Simpson and Gilmartin. 

 1970). 



Orr (1969) conducted field observations and reviewed accumulated data sub- 

 sequent to the spill. He stated (p. 7) : "A review of recorded dead gray whales 

 found during migration along the California coast during the past 10 years 

 revealed that the incidence of mortality in early 1969 was not unusually high.'' 

 No mortality among seals, .sea lions, or cetaceans was found that appeared 

 abnormal or could be attributed to the oil spill. Orr concluded "* * * that no posi- 

 tive evidence was obtained to show that any gray whales died on their north- 

 ward migration from the effects of crude oil pollution." 



Orr participated in field studies of wildlife affected by the extensive Golden 

 Gate .spill of Bunker "'C" oil that occurred on IS .January 1971. Although he 

 reported massive destruction of bird life, he reported no effect on marine mam- 

 mals fOrr, 1971). 



Of the examined California sea lions and other seals that were found dead or 

 dying on southern California beaches, none have had petroleum products on 

 their bodies (Personal communications to K. W. Kenyon from L. A. Grinar, 

 1971). 



Various observers (Personal communications to K. W. Kenyon) have remarked 

 on the general absence of oil on the bodies of marine mammals found on beaches. 

 The large numbers of dead or dying marine birds observed on the same beaches 

 of California, Oregon, and Washington have been interpreted to indicate that oil 

 has been present in the marine environment at various times over a period of 

 years. Thus, marine mammals would appear to be able to avoid petroleum pollu- 

 tion and are less susceptible to damage from petroleum products than are birds. 



Sergeant concluded (1970) : 



"Sea mammals have a notal)le ability' to avoid oil slicks. However, young harp 

 seals heavily oiled by Bunker "C" oil in the Gulf of St. Lawrence in March 

 1969, swam 200 miles northward on the normal migration route and there was 

 no evidence of severe deaths. Gray seals avoided Bunker "C" at Chedabucto Bay, 

 Nova Scotia, in February 1970, and deaths attributed to oil were few (B. Beck, 

 Personal communication). 



"Nevertheless circumstantial evidence accumulates of the cumulative effects 

 of pollutants. Small Cetacea are now rare in the southern North Sea (W. Van 

 Utrecht, Personal communication), where heavy ship traffic, oil and gas explora- 

 tion and industrial contamination might all be contributory factors to either avoid- 

 ance or death." 



MARINE VEGETATION 



The higher the concentrations of low-boiling compounds, unsaturated com- 

 pounds, aroma tics and acids in oil, the more toxic it is to plants (Baker, 1970). 



