A Warmer North Pacific Is Staying Warmer, with Dramatic Impact on Marine Life

Warm sea temperatures are persisting in the North Pacific longer than at any other time on record, according to a new study published this week, and it is having a dramatic effect on distribution of marine life.

In the last year and a half the northeastern part of the Pacific Ocean, between Hawaii and the mainland of North America, has been warmer than at any time since 1900, when such record-keeping began.  Sea temperatures there are between 5 degrees to 9 degrees Fahrenheit higher than is typical for this time of the year.

The study, published Monday in the Proceedings of the National Academy of Sciences by researchers at the University of Exeter in England, explores this climate pattern, which has in turn changed the habitats of sea life.  Many subarctic species unable to adapt to warmer temperatures are seeking colder waters, displacing some populations by thousands of miles. Some squid and tuna that are typically found off the coast of Southern California are now being seen as far north as the coast of Oregon and Washington.

Over the last several decades, the world's oceans, including the North Pacific, have been warming at an unprecedented pace.  Typically, oceans go through a warming-and-cooling cycle that can last a few years to decades—a relatively short period in climate research.  But increasingly, the extreme temperatures are becoming longer-lived, the Exeter researchers have found.
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As temperatures rise, the seas expand, also contributing marginally to sea level, which is rising mostly because of melting ice caps and glaciers.

In the large expanse of abnormally warm water in the North Pacific dubbed "the blob" by oceanographers, the displacement of fish species has disrupted the marine food web.  Baby sea lions, which feed on anchovies, squid and shellfish, don't have the strength to swim further to catch food.  As a result, thousands have been washing up onshore in record numbers this year, prompting the National Oceanic and Atmospheric Administration to declare it an "unusual mortality event."

The changes in sea temperatures are also impacting the fishing industry, forcing it to travel further to reach fish populations that have moved away from their traditional waters.  Researchers have predicted that with worsening climate change, marine fisheries will face higher costs and lower productivity.

That trend is already evident in the Pacific Northwest, where a double whammy of drought and warmer waters has caused massive Chinook salmon die-offs in the Sacramento River.

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