Between 2013 and 2014, a huge mass of hot water was detected in the North Pacific area, which intensified in 2015-2016 due to the El Niño phenomenon and caused an unprecedented environmental disaster. It was called the blob (the Drop), and its effects were produced on the entire trophic chain, consequently affecting the fishing resources of the area.
Now, a study published in the journal PLOS ONE shows the relationship between this phenomenon and the death of about a million common guillemots ( Uria aalge ) on the coasts of North America during those years.
The common guillemot is a bird that usually spends a good part of its life at sea, and comes to the coasts only during the breeding season. During this period, the observation of the rocky cliffs where guillemots and other seabirds make their sunsets is a real spectacle, since there hundreds and even thousands of couples gather and make up a kind of ‘mini cities’ animals.
However, during the years 2015 and 2016, the spectacle observed on the beaches of the North Pacific should not have been so rewarding, since some 62,000 guillemots were found along the coast between California and Alaska , a number around a thousand times higher than what was counted in other years. Experts estimated that the actual number of deaths was probably around a million, since only a fraction of the bodies would eventually reach the shore.
They starved
The guillemot is a bird with a very demanding metabolism, since every day it must consume around half its weight in the form of small fish: sardines, anchovies, herring and even salmon babies. On the other hand, guillemots are expert divers, capable of swimming a distance equivalent to two football fields to get their prey.
However, despite their great adaptability, the hot drop was too much for them. As the authors of the study explain, the decrease in the availability of prey as a result of the warming of the waters , as well as greater competition with other predators that registered changes in their metabolism and increased their demand, were the causes of these massive deaths.
“Imagine that any emergency panic breaks out and everyone runs to supermarkets at the same time to stock up. And, at the same time, the delivery trucks stop supplying the stores with the same frequency ”, explains Julia Parrish, a researcher at the University of Washington and one of the authors of the work. “Beyond the ocean wave per se , what happened was a squeeze of the ecosystem: fewer forage fish, more small prey and a strong increase in competition with other large predators such as Pacific cod.”
A large-scale disaster
The case of the guillemots is one of the most striking, but it is only the tip of the iceberg. The great wave of the Pacific killed the life of fish, birds and cetaceans , displaced species outside their current range of distribution and caused algae explosions (something similar to what happened in the Mar Menor in 2016) that unbalanced the entire ecosystem. As a consequence, in addition, the fishing activity on the west coast of the Pacific suffered millions of dollars in losses.
“The murderous case was of unprecedented magnitude,” explains John Piatt, a research biologist at the Alaska Science Center of the US Geological Survey. “It is surprising, alarming, a red flag warning about the tremendous impact that sustained ocean warming can have on the marine ecosystem.”
And it is that scientists agree that this type of event will be the norm from now on. The year 2019 has broken absolute records for the temperature of the ocean water, and at the beginning of it a new wave was detected that would be beginning to form in the Gulf of Alaska. Using climate projection models, specialists already warn that marine heat waves will be forty times more frequent by the end of the century than now.
“All this, as well as the massive mortality of such emblematic species as the puffin, shows us that the warming of the ocean will totally change the ecosystems, and the environment in which the seabirds will have to survive will be very different, ” concludes Parrish.
Referencia: Piatt et al 2020. Extreme mortality and reproductive failure of common murres resulting from the northeast Pacific marine heatwave of 2014-2016. PLOS ONE doi.org/10.1371/journal.pone.0226087
