The West Coast Is in Hot Water

Move over polar bears. Are starving sea lion pups the new face of climate change?

This year’s slew of hungry pups washing ashore in California, which has generated a slew of media coverage replete with heart-tugging images, has roots in natural temperature fluctuations in the ocean. But in the coming decades, human-induced warming could make these types of conditions more common. And sea lion pups are just the tip of a larger shift in the Pacific and the rest of the world’s oceans if human emissions continue to warm the planet. In recent weeks, emaciated young sea lions have been washing up on California beaches. Roughly 1,800 stranded pups have been found on California beaches through the first two-and-a-half months of 2015. That’s well above the 100 or so that usually turn up through the end of March and “at least as high as anything in the historical record,” according to Nate Mantua, a scientist at the Southwest Fisheries Science Center in La Jolla, Calif.

In 2013 and 2014, large numbers of disheveled sea lion pups were also stranded on California’s beaches, though not at the same levels as this year. One of the main causes has been the unusual and in some cases, record setting — warm water off the West Coast of the U.S. and stretching all the way to the Gulf of Alaska. The warm water is less rich in nutrients and the types of microscopic organisms and fish upon which sea lions usually feed. That has forced sea lion moms and pups alike to forage further for food, a tiring proposition for young sea lions. While the sea lions have been the face of the recent intrusion of warm water, ecosystem disruptions are visible throughout the stretch of the eastern Pacific and Gulf of Alaska. Cold water copepods — small crustaceans at the base of the food chain — populations have dropped off sharply in the past year, while their warm water (less nutritious) brethren have shown up in huge quantities.

Further up the food chain, skipjack tuna have turned up in Alaska, thousands of miles beyond their usual range and Mantua said, “sportfish like marlin — things people travel to fish for in Baja — they’re catching them for day trips in southern California.”The warm water in the eastern Pacific over the past two years is a harbinger of things to come for the region. Ocean temperatures have been rising around the world and are expected to keep warming, and the eastern Pacific could see the odd conditions of the past two years become commonplace by mid-century. Just how far-reaching the impacts will be and which species will adapt and which will fail to is something scientists are still trying to untangle.

http://www.weather.com/science/environment/news/west-coast-hot-water-rising-temperatures-climate-change