By Kevin Byrne, AccuWeather.com Staff Writer

October 3, 2014

Unusually high water temperatures throughout the North Pacific Ocean have brought concerns from researchers about how it could affect native species of fish as well as sightings of uncommon species.

The three areas of the North Pacific with the most notable warming trend include the Gulf of Alaska, the Bering Sea and an area off the coast of Southern California down to Baja California, Mexico, with temperatures as high as 5 degrees above average.

These sea surface temperature anomalies have remained this way for more than a year, one of the longest stretches on record, according to researchers with the National Oceanic and Atmospheric Administration (NOAA).

This is a sea surface temperature anomaly map in the North Pacific Ocean. The darker the red, the farther above average the sea surface temperature, according to NOAA. (Photo/NOAA)

A big concern for native species of fish, such as salmon, is that the primary food items they eat may no longer be available, Weitkamp said.

Potentially adding further stress to the situation, warm water also increases the metabolic rate of the fish so they have to eat more in warmer water, but there may not be enough to eat because the conditions are not suitable for their food items, Weitkamp said.

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Nate Mantua, leader of the landscape ecology team at the NOAA Southwest Fisheries Science Center, attributes these conditions in the Gulf of Alaska to the same ridge of high pressure that’s believed to have contributed to California’s extreme drought. Storms and winds that commonly cool and stir the sea surface have been quelled by the ridge.

“If the warming persists for the whole summer and fall, some of the critters that do well in a colder, more productive ocean could suffer reduced growth, poor reproductive success and population declines,” Mantua said in a NOAA Fisheries article.

“This has happened to marine mammals, sea birds and Pacific salmon in the past. At the same time, species that do well in warmer conditions may experience increased growth, survival and abundance,” Mantua said.

Another effect likely brought about by the noticeably warmer waters is observations of different species of fish that are not known for frequenting this part of the ocean.

Earlier this past summer, a research vessel found a thresher shark in the Gulf of Alaska, which was the northernmost documented catch of the species, according to Michael Milstein, a spokesman for NOAA Fisheries.

“Thresher sharks are know for preferring warm waters,” Milstein said.

More: http://www.accuweather.com/en/weather-news/warm-north-pacific-waters-threaten-fish/34699318