tincan
Well-Known Member
Some more interesting info on seal predation of salmon in BC.
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https://www.cbbulletin.com/439218.aspx
Study: Harbor Seals Target Salmon Juveniles Of Conservation Concern In Salish Sea
Posted on July 7, 2017 (PST)
Harbor seals eat both adult and juvenile salmon, but the adults they target in the autumn are from healthier stocks of fish (of less conservation concern) than the juveniles they target in the spring, according to a recent study of prey preferred by harbor seals in the Straits of Georgia in British Columbia.
Harbor seals tend to eat adult chum and pink salmon during the fall season, but they target larger juvenile chinook, coho and sockeye salmon, even though there is a higher abundance of chum salmon available in the spring. Those species, according to the study, are of greater conservation concern.
Harbor seals are abundant, year-round predators in the Salish Sea, that have high energetic needs for fish resources with a potential that can significantly impact salmon species that either reside or migrate through the inland marine waters of the Pacific Northwest.
With about 40,000 of the seals in the Straits of Georgia, the impact on juveniles is huge. Harbor seals consume about 2 kilograms of fish per day (4.4 pounds) and if those are all juvenile salmon, the total impact for coho salmon alone amounts to 5.7 million in one month (assumes the average hatchery coho smolt weighs 20 grams (0.044 pounds) and a seal diet is 4.8 percent coho smolts). This may be “driving regional survival patterns of Chinook and coho salmon,” the study concludes.
“While most people suspect that seals devour adult salmon of concern (like that seal that stole the prize chinook off your fishing line), we found that harbor seals mainly eat adult chum and pink salmon in the Strait – species that are doing pretty well overall,” said researcher Austen Thomas PhD, research scientist with Smith-Root, Inc. “However, when we looked at the juvenile salmon they were eating, seals appeared to consume more chinook, coho and sockeye salmon than they did juvenile pink and chum
.... con't...
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https://www.cbbulletin.com/439218.aspx
Study: Harbor Seals Target Salmon Juveniles Of Conservation Concern In Salish Sea
Posted on July 7, 2017 (PST)
Harbor seals eat both adult and juvenile salmon, but the adults they target in the autumn are from healthier stocks of fish (of less conservation concern) than the juveniles they target in the spring, according to a recent study of prey preferred by harbor seals in the Straits of Georgia in British Columbia.
Harbor seals tend to eat adult chum and pink salmon during the fall season, but they target larger juvenile chinook, coho and sockeye salmon, even though there is a higher abundance of chum salmon available in the spring. Those species, according to the study, are of greater conservation concern.
Harbor seals are abundant, year-round predators in the Salish Sea, that have high energetic needs for fish resources with a potential that can significantly impact salmon species that either reside or migrate through the inland marine waters of the Pacific Northwest.
With about 40,000 of the seals in the Straits of Georgia, the impact on juveniles is huge. Harbor seals consume about 2 kilograms of fish per day (4.4 pounds) and if those are all juvenile salmon, the total impact for coho salmon alone amounts to 5.7 million in one month (assumes the average hatchery coho smolt weighs 20 grams (0.044 pounds) and a seal diet is 4.8 percent coho smolts). This may be “driving regional survival patterns of Chinook and coho salmon,” the study concludes.
“While most people suspect that seals devour adult salmon of concern (like that seal that stole the prize chinook off your fishing line), we found that harbor seals mainly eat adult chum and pink salmon in the Strait – species that are doing pretty well overall,” said researcher Austen Thomas PhD, research scientist with Smith-Root, Inc. “However, when we looked at the juvenile salmon they were eating, seals appeared to consume more chinook, coho and sockeye salmon than they did juvenile pink and chum
.... con't...
