Inter-Research > MEPS > v719 > p1-40  
Marine Ecology Progress Series

via Mailchimp

MEPS 719:1-40 (2023)  -  DOI:

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

Gregory T. Ruggerone1,*, Alan M. Springer2, Gus B. van Vliet3, Brendan Connors4, James R. Irvine5, Leon D. Shaul6, Matthew R. Sloat7, William I. Atlas7

1Natural Resources Consultants, Seattle, WA 98199, USA
2College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
3PO Box 210442, Auke Bay, AK 99821, USA
4Fisheries and Oceans Canada, Institute of Ocean Sciences, Sidney, BC V8L 5T5, Canada
5Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
61316 3rd St., Douglas, AK 99824, USA
7Wild Salmon Center, Portland, OR 97209, USA
*Corresponding author:

Abstract: In response to a climate regime shift in 1977 and general heating of the North Pacific Ocean, pink salmon Oncorhynchus gorbuscha abundance reached record highs during 2005-2021, comprising 70% of all Pacific salmon. Pink salmon are approximately 25 times more numerous in odd- than even-numbered calendar years in some major North Pacific ecosystems, a unique demographic pattern analogous to repeating whole ecosystem treatment-control experiments. We found compelling examples indicating that in odd years, predation by pink salmon can initiate pelagic trophic cascades by reducing herbivorous zooplankton abundance sufficiently that phytoplankton densities increase, with opposite patterns in even years. Widespread interspecific competition for common-pool prey resources can be dominated by pink salmon, as indicated by numerous biennial patterns in the diet, growth, survival, abundance, age-at-maturation, distribution, and/or phenology of ecologically, culturally, and economically important forage fishes, squid, Pacific salmon and steelhead trout Oncorhynchus spp., seabirds, humpback whales Megaptera novaeangliae, and endangered southern resident killer whales Orcinus orca. In aggregate, the evidence indicates that open-ocean marine carrying capacity in the northern North Pacific Ocean and Bering Sea can be mediated by top-down forcing by pink salmon and by ocean heating, and that large-scale hatchery production (~40% of the total adult and immature salmon biomass) likely has unintended consequences for wild salmon, including Chinook salmon O. tshawytscha, and many other marine species. Further investigation of the effects of pink salmon on other species will increase our knowledge of ecosystem function and the important role top-down forcing plays in the open ocean

Key words: North Pacific ecosystems · Oncorhynchus gorbuscha · Competition · Trophic cascade · Carrying capacity · Climate change · Ocean heating · Ecosystem services

Full text in pdf format
Supplement 1
Supplement 2
Cite this article as: Ruggerone GT, Springer AM, van Vliet GB, Connors B and others (2023) From diatoms to killer whales: impacts of pink salmon on North Pacific ecosystems. Mar Ecol Prog Ser 719:1-40.

Export citation
Share:    Facebook - - linkedIn

Next article