Ruggerone GT, Springer AM, van Vliet GB, Connors B, Irvine JR, Shaul LD, Sloat MR, Atlas WI

From diatoms to killer whales: impacts of pink salmon on North Pacific ecosystems

In response to ocean heating caused by climate change, coupled with industrial-scale hatchery production, pink salmon have reached record-high numbers in the North Pacific and now constitute 70% of all Pacific salmon. Their unique two-year life cycle leads to exceptional abundances in odd-numbered years and low abundances in even-numbered years. This provides in effect a natural treatment-control experiment to test hypotheses about the role they play in the ecology of species that compete with them for prey and about ecosystem function. A synthesis of studies spanning decades found strong evidence that pink salmon initiate pelagic trophic cascades and adversely affect the growth, survival, productivity, and abundances of forage fishes, squid, other Pacific salmon, seabirds, humpback whales, and killer whales.

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