Between the summer of 2015 and the spring of 2016, thousands of penguin-like birds called “common murres” were found dead on Pacific beaches from Alaska all the way down to California. Researchers concluded that approximately 62,000 dead or dying birds appeared on beaches and that around 1 million murres died in total. John Piatt, a research wildlife biologist at the US Geological Survey and the lead author of a new study on the die-off says while some murre deaths in any given season are normal, what happened in the Pacific in 2015 and 2016 was “beyond anything anybody’s ever seen.”
Piatt and his team began to research what may have been responsible for the demise of the seabirds. They linked the murre die-off, which killed about 10 percent to 20 percent of the population, to a colossal mass of warm ocean water, called it the “Blob,” that warmed the ocean temperatures enough to severely disrupt the ecosystem. They have published their analysis in a new paper in the open-access journal PLOS ONE.
In the winter of 2013, a mysterious blanket of abnormally warm water appeared in the Pacific Ocean and wreaked havoc on marine ecosystems for three long years. The water temperature intensified during the summer of 2015 due to a powerful weather phenomenon called El Nino, and created the Blob, a 1,000-mile stretch of ocean warmed 3 to 6 degrees Celsius (5.4 to 10.8 Fahrenheit) higher than normal. A high-pressure ridge kept the heat in the water, without storms to help cool it down.
Those few degrees of warming caused a huge drop in the production of microscopic algae that feed a range of animals. Small fish species that prefer colder waters, which tend to be fattier, were replaced by warmer water species of lower nutritional value. The increase in water temperatures also would have caused larger fish species to increase their food consumption by up to 70 percent. This made it harder for top predators, like the murres, to find enough food.
Common murres are one of the best adapted seabirds in the northern hemisphere, able to catch fast-moving prey and to dive to the depth of two football fields. The small seabird, which weighs about 2 pounds, must eat 56 percent of its body mass each day to survive and can starve in as little as three days. The birds that washed up on the shores of the Pacific were severely emaciated and appeared to have died of starvation.