Largest predatory slaughter ever: 10 million fish devoured by cods in Norway

In just a few hours, millions of fish were devoured. “This is the first time you’ve seen a large-scale predator-prey interaction,” say MIT researchers.

Nicholas Makriswrote, together with other MIT ocean engineers, explaining how they observed the dynamics of the event that occurred off the Norwegian coast, and which is claimed to be the largest predatory massacre ever recordedthrough the echo of sound waves from the animals’ swim bladders.

“Cod have large swim bladders which have a low resonance, like a Big Ben bell,” the scientists write. Unlike the fish that was “eaten”, the capelimwhich “has tiny swim bladders that resonate like the highest notes on a piano.”

What was carried out by the engineers was published in Nature on October 29 and may be important for showing that “natural events of catastrophic predation can alter the local balance between predator and prey in a matter of hours”, as Makris explains in the article.

Newly analyzed data dating back to 2014 captured up to 23 million capelins joining together. In response, 2.5 million Atlantic cod, predators, also organized themselves into a school, “preparing for the feast”, explains the

“If they are close enough to each other, these fish can take on the average speed and direction of the other fish they can sense around them, thus forming a massive, coherent school,” explains Makris, who says that 97% of migratory fish species are currently at risk of extinction, which includes highly valued species such as Atlantic salmon.

Fortunately, says the researcher, there are billions of capelins, so this event will have eliminated only 0.2% of the population. But when it comes to , the case changes.

The MIT team has already used it to explore the population dynamics of cod populations, which are also in decline, explains Science Alert. The researchers found that, If populations drop below the average number of individuals in a school, it is much more difficult for them to recover.

“As the number of these hotspots decreases due to climatic and anthropogenic pressuresthe type of natural “catastrophic” predation event we see of a keystone species can have dramatic consequences for that species, as well as for the many species that depend on it.”