251 



DRAFT 



'Harvey estimated that harbor seals consumed 1.3 million pounds of 

 salmon in Oregon in 1980... ' 



'Because the Oregon harbor seal population has increased to 10,000 

 animals since 1980. it would now consume approximately 1.8 million 

 pounds of salmon... ' 



The report uses an estimate from Harvey (1988) that seals consumed 1.3 million 

 pounds of salmonids in Oregon in 1980 to conclude that this represents 30 percent of 

 the 1980 landings. This conclusion does not recognize that the majority of the 

 salmonids Harvey reported to have been consumed by seals were steelhead, and not 

 "feeder" chinook or coho as sUted in the report. The authors then use the (incorrect) 

 figure of 10,000 seals in Oregon and extrapolate to estimate that 1.8 million pounds of 

 salmon were consumed by seals in 1990. The report then incorrecdy uses this data 

 (which includes Harvey's steelhead estimate) to compare these predation loss estimates 

 to ocean commercial troll landings of salmon. 



The report uses incorrect figures and comparisons to report increases in pounds of 

 salmon consumed by seals statewide and in the Columbia River between 1980 and 

 1990. These calculations do not constitute valid scientific methodology, and the 

 conclusions drawn are not supported by the data. 



'Numerically, salmon may represent less than one percent of the harbor 

 seals diet. . . ' 



The report acknowledges that, based on Harvey (1988), salmon numerically comprise 

 less than one percent of the seals diet in Oregon. However, the report suggests that 

 salmon (by weight) can comprise at least 10 percent of the "diet requirement". This 

 statement is misleading: if less than one percent of the fish eaten by seals is salmon, 

 then, less than one percent of the fish eaten is salmon. Rephrasing the statement does 

 not change the reality. Seals, nor any other marine mammal, require salmon in their 

 diet. What is required is a certain biomass of food, usually fish, of which salmon is a 

 relatively unimportant component in the overall diet. 



Other scientific data concerning harbor seal food habits were not presented in the 

 report, including dau collected by ODFW and WDW in the Columbia River. In 1986, 

 1987, and 1988 the jgastrointestinal tracts of 84 harbor seals collected during winter 

 salmon and steelhead run periods were examined for food habits analysis. Eulachon 

 was the most important prey item, by frequency and by weight, occurring in 100% of 

 the seal stomachs. Longfm smelt and lamprey occurreid in 14.3% and 9.5% of the 

 samples respectively. Five other species of fish were consumed by these seeds. No 

 salmon or steelhead had been consumed by any of the 84 harbor seals in this sample. 

 This was the largest collection of seal stomachs for food habits analysis that has been 

 completed in Oregon to date. 



This study of the Columbia River suggests that harbor seal predation on salmon and 

 steelhead is minimal; however, it would not be valid to extrapolate these results to the 

 entire Oregon coast for all seasons of the year to imply that harbor seals do not 

 consume salmonids. 



A-45 



