2015 and 2016 were the two hottest years ever recorded; we should not be surprised therefore to find our oceans to be showing signs of stress as the delicate balanced eco system is also being stretched to its limit.
A deadly patch of warm water along the American West coast called the ‘Pacific blob’, stretching all the way from California up to the Gulf of Alaska, Has killed thousands of California sea lions in 2015. Many starved as they struggled to find food in an unusually warm eastern Pacific. Strange exotic tropical fish have been reported off the coast of Alaska. In the winter of 2015 blue-footed diving seabirds called Cassin’s auklets, have been washing up dead by the thousands on beaches from San Francisco to Alaska, it is thought more than 250,000 died from lack of food. An unprecedented die off which began in 2011 along the West coast of North America when billions of sea urchins and sea stars died suddenly in what was 'one of the most unusual and dramatic die-offs marine biologists have ever recorded.'
The Culprit: Warm Water?
Bill Sydeman, a senior scientist at California's Farallon Institute, said he believes the most likely scenario is that the deaths are related to a massive blob of warm water that heated the North Pacific last year and contributed to California's drought and to 2016 being the hottest year on record.
That water was hotter and stayed warm longer than at any time since record-keeping began. It stretched across the Gulf of Alaska, where a high-pressure system blocked storms, preventing the water from churning to the surface and mixing with air. More warm water eventually moved inward along the coast as far south as California, altering how favorable the environment was for the zooplankton that many fish and birds, including Cassin's auklets, feed on.
Last year tens of thousands of common murres were the victims, an abundant North Pacific seabird, starved and washed ashore on beaches from California to Alaska, researchers have pinned the cause to unusually warm ocean temperatures that affected the tiny fish they eat.
A year after tens of thousands of the common murres died, John Piatt, a research wildlife biologist for the U.S. Geological Survey claims the deaths of the common murres is an indicator of the regions' health.
Elevated temperatures in seawater affected wildlife in a pair of major marine ecosystems along the West Coast and Canada, said
"If tens of thousands of them are dying, it's because there's no fish out there, anywhere, over a very large area," Piatt said.

It is thought 500,000 of the common murres, who look like thin penguins, died last year all though this could be just a conservative guess because only a fraction of the dead birds likely reached the shore.

http://www.thebigwobble.org/2017/02/mass-death-of-seabirds-in-western-us.html