In a significant revelation, researchers from the University of Washington have traced the alarming decline of the common murre population in Alaska back to a marine heatwave known as "The Blob," which peaked between 2013 and 2016. This phenomenon, characterized by a massive pocket of warm water in the northeastern Pacific, led to one of the largest recorded marine bird die-offs, with an estimated 4 million murres lost.
The Blob's emergence was driven by persistent high-pressure systems, raising ocean temperatures by 2 °C over vast areas. This drastic change disrupted marine ecosystems, resulting in a critical reduction in available prey and significant thermal imbalances. Affected species included not only murres but also fur seals, sea lions, salmon, cod, and gray whales.
Between 2014 and 2017, many species struggled to reproduce, but murres suffered the most. Heather Renner, a biologist with the U.S. Fish and Wildlife Service, remarked, "We immediately understood this was a major catastrophe." The study, published in the journal Science, analyzed three decades of data, revealing that the murre population in Alaska was halved due to the heatwave.
Renner's research, which included the identification of 62,000 dead murres along the U.S. West Coast, suggests that these numbers represent only a fraction of the actual mortality. Current estimates indicate that recovery for the murres could take at least three years, yet seven years post-event, populations remain significantly low.
This situation raises concerns about potential long-term ecological shifts within marine habitats, with fragile ecosystems possibly on the brink of collapse. The findings underscore the pressing need for further research into the impacts of climate change on marine biodiversity and the resilience of affected species.