Scientists discover 10 million fish eaten in biggest feeding frenzy ever recorded

Scientists have observed the biggest feeding frenzy ever recorded after a swarm of cod ate 10 million fish in a matter of hours.

Our vast oceans are places where scientists continue to make surprising discoveries, but while one man was horrified to witness fish eating a salmon fillet he dropped into the sea, sea animals eating one another is a very natural phenomenon.

A study conducted by the Massachusetts Institute of Technology (MIT) alongside Norwegian oceanographers found that a wild feeding frenzy off the coast of Norway is one of the biggest on record.

In the Norwegian Sea, the team observed a swarm of Atlantic cod prey upon over 10 million capelin fish within just a few hours.

A capelin is a small Arctic fish that is around the size of an anchovy. In February, they migrate in their billions from the Arctic ice sheet to the sea off the Norwegian coast to spawn.

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This pattern also coincides with the southerly migration of the Atlantic cod, which is one of the capelin’s main predators.

While this has long been known, it is only now that scientists have gained an insight into the extent of the predation.

In a study published in the Communications Biology journal, the experts were able to look at sonar data recorded in 2014 and recreate real-time maps of the ocean using advanced acoustic imaging technology.

They found that the capelin gathered in a large shoal that spanned tens of kilometres and contaminated 23 million fish, making them a target for predators and potentially leaving the species vulnerable in the future as climate change impacts migration patterns.

“It’s been shown time and again that, when a population is on the verge of collapse, you will have that one last shoal. And when that last big, dense group is gone, there’s a collapse,” Nicholas Makris, professor of mechanical and ocean engineering at MIT, explained in a press release. “So you’ve got to know what’s there before it’s gone because the pressures are not in their favour.”

The experts explained that, while this one predation event isn’t likely to have greatly affected the population numbers of capelin, representing 0.1 per cent of the fish that spawned in the region, as climate change causes the Arctic sheet to retreat, they could become vulnerable at a later point as they will have to swim further to spawn.

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