Nearly 10 million munched on within hours in major sea massacre

Marine carnage was witnessed in the seas recently when a massive swarm of cod off the coast of Norway rapidly gobbled up millions of migrating capelin fish. The researchers tracking the cod say that it appears to be the largest predatory massacre of its kind ever recorded by humans.

Several species of marine life are known to come together for protection and migration purposes. This is when resourceful predators in search of food attack them. However, scientists have only recently been able to observe large populations of fish moving around and see in real time what a massive dinner attack of this scale looks like.

Researchers published their findings in a paper in the journal Nature Communications Biology.

Add WION as a Preferred Source

Oceanographers in Norway and at MIT used sonar-based technique called Ocean Acoustic Waveguide Remote Sensing, or OAWRS to record one such attack.

They followed populations of capelin—small anchovy-like fish—during the height of their spawning season in the coastal waters near Norway. The large group then comes in contact with larger Atlantic cod, their primary predator.

Millions of fish became food within hours

The capelin are initially scattered but soon bunch together into a shoal of about 23 million fish spanning miles. Upon encountering the shoal, the cod also gather into a group and feast on the capelin.

Also Read:California lake full of cyanide hiding previously unknown creatures

The researchers say that the cod munched on around 10 million capelin within four hours of the shoal first forming.

“Species interaction studies for various areas and time periods using OAWRS could facilitate a new and better understanding of the function of large marine ecosystems as well as supporting quantification of key processes in the assessment and management of marine resources over wide areas,” the study authors wrote in the paper.

Losing millions of capelin might look like a lot but isn't when you consider their total strength. Billions of capelin migrate between the waters of the northeast Atlantic ocean, so the cod attack likely only diminished their total population by only about 0.1% of their total population in the area that year, as per the researchers.

Besides, prey-predator relationship is how a balance is maintained in the ecosystem.