Climate Change and Pacific Cod
Threatened by warming waters, can climate-ready fisheries help this keystone species survive into the future?
About this story map
Fisheries and the communities that depend on them must adapt to rapidly changing ocean conditions. In the North Pacific Ocean, the Gulf of Alaska (GOA) Pacific cod population collapsed after an extreme marine heatwave event 2014-2016.
Communities and fisheries in the GOA are still picking up the pieces after the cod collapse. We are just beginning to understand the long-term consequences of heatwaves on the Alaskan ecosystem.
This story map discusses the biological and physical events leading up to the Pacific cod collapse as well as climate-ready fishery management solutions to help the region’s managers and communities adapt to climate change.
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Pacific Cod
A keystone species in the North Pacific
What is a Pacific Cod?
- Pacific cod Gadus macrocephalus is a ray-finned “true cod,” found across the continental shelf, ranging from the Yellow Sea to the
- Bering Strait, along the Aleutian Islands, to as far south as Los Angeles.
- Pacific Cod have 3 dorsal fins and catlike whiskers on their bottom jaw.
- They can grow to be up to 50 inches in length, 50 pounds in weight, and up to 18 years of age.
- Pacific cod swim in large schools at depths up to 3,000 feet.
- Pacific cod is a significant source of protein and vitamin A, vitamin D, vitamin E, and omega-3 fatty acids.
- As adults, Pacific cod are voracious predators that live near the seafloor and forage on fish, crab, shrimp, and other invertebrates.
Pacific cod are vulnerable in warm water
Pacific cod are very sensitive to temperature. Pacific cod egg hatch success declines substantially in water above or below 4-5°C. Warmer waters can also harm maturing cod by reducing growth and reducing prey availability.
Economics/fleet profile
- GOA Pacific cod support a culturally and economically important fishery in Alaska.
- GOA Pacific cod catch averaged nearly 77,000 tons from 2010 to 2016.
- In 2017, Alaska-wide Pacific cod first wholesale production value was at a 12-year peak, worth an estimated US$510 million.
- Pacific cod is also a significant protein source for human consumption internationally.
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Marine Heatwaves
Climate change has made marine heatwave events worse around the world
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A marine heatwave (MHW) is typically defined as 5 days or more where the sea surface temperature is unusually high.
MHWs globally are becoming more frequent and severe due to anthropogenic greenhouse gas emissions.
From the winter of 2013/2014 – 2014/2015, the northeast Pacific experienced the greatest MHW recorded since 1880.
Physical changes
The GOA MHW was unique with warm waters persisting from the sea surface to the seafloor.
The Pacific Decadal Oscillation (defined by SST anomalies in the North Pacific) reached the highest winter value on a record extending back to 1900.
Biological changes
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