Gulf of Alaska heating up, not at heat wave yet

Jun 10, 2020

Credit National Marine Fisheries Service / National Marine Fisheries Service

Temperatures in the Gulf of Alaska are on the upswing again, which could be bad news for fish and other marine animals.

Last summer saw scorching temperatures across Alaska, including breaking the 90-degree mark on the Fourth of July in Southcentral. The ocean hangs onto abnormal temperatures for some time, leading to sea surface temperature anomalies and can have negative impacts on fish populations.

The National Marine Fisheries Service noted that while temperatures trended down during the cold winter months until March, they crept up again in June.

The temperatures have not yet hit the threshold to be considered a marine heat wave, which requires that they be above the 90th percentile for five or more days.

The Gulf of Alaska has been increasingly experiencing heat waves the last six years, including the famous warm water anomaly known as “the Blob.” Warm temperatures can spell bad news for fish, as they change plankton production and reduce food availability for feeder fish, which larger fish, like salmon, eat. Species higher up on the food chain, like seabirds and whales, have experienced lower juvenile survival and higher mortality linked to this, according to NMFS.

The agency plans to provide updates about marine heat waves via social media this summer.

Reach Elizabeth Earl at eearl@kdll.org.