Food quality matters for southern resident killer whales

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.