Not all Chinook salmon are created equal, and this has a major impact on the energetics for southern resident killer whales. A recent study quantified the lipid content in Fraser River Chinook salmon — the southern resident’s preferred meal — and found that spring-run Chinook salmon, the earliest to arrive to the Salish Sea are lipid-rich and energy dense; a critical factor for the killer whales who prey on them. Fraser River Chinook salmon that come later in the season have lower energy density.

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