A massive heat wave in the Pacific Ocean, known as “the blob,” has caused the largest single species die-off in history, killing half of Alaska’s common murre population.
The common murre, a small seabird resembling a flying penguin, relies on fish, squid, and crustaceans for food. The heat wave between 2014 and 2016 raised ocean temperatures by seven degrees Fahrenheit, destabilizing the marine ecosystem and diminishing the food supply.
Scientists estimate that 8 million common murres lived in Alaska before the heat wave, but now only 4 million remain. A study analyzing colony survey data found that colonies declined by 50% to 75% after “the blob,” resulting in an estimated 4 million deaths due to starvation and lack of food.
Researchers attribute the deaths primarily to shifts in the food web, leaving murres without enough food. The impact on Alaskan Native communities is significant, as murres were traditionally an important source of meat and eggs.
The study’s lead author, Julia Parrish, notes that “the effect of the heat wave wasn’t via thermal stress on the birds, but rather shifts in the food web leaving murres suddenly and fatally without enough food.” The researchers have found no evidence of recovery since the die-off occurred.
This devastating event highlights the catastrophic impact of oceanic warming on animal populations. With climate change leading to more frequent and intense marine heat waves, the consequences for seabirds like common murres are dire. As Parrish warns, “We may now be at a tipping point of ecosystem rearrangement where recovery back to pre-die-off abundance is not possible.”
Source: https://www.dailymail.co.uk/sciencetech/article-14229893/ocean-blob-deaths-common-murres-largest-species-execution-history.html