Large whales eat 3 times as much as previously thought, which means killing them for food and lard is even more harmful to the environment

Scientists near Antarctica interact with humpback whales. Duke University Marine Robotics and Remote Sensing under NOAA License 1 4809 – 03 and ACA Licenses 2015 – 011 and 2020 – 016

• Marine ecosystems were thrown out by a lot of hunting of large whales.

• Whales that eat krill keep marine life in balance – and now a study shows that they eat more than expected.

• The finding means that every single whale is even more important than people were aware of.

Researchers have found that large whales eat at least three times as much as previously thought, a discovery that highlights their importance in keeping the oceans healthy.

The study, published Wednesday in the peer-reviewed journal Nature, gives clues as to why it was so devastating for the marine environment to wipe out millions of the largest whales on the planet.

Rebuilding the whale population can do wonders for marine environments and may even help rebuild declining fish stocks, two researchers told Insider.

A humpback whale eats in the Stellwagen Bank National Marine Sanctuary Elliott Hazen

The Krill paradox

From 1900 to 1970, industrial whaling wiped out approx 1.5 million large whales around Antarctica.

“The largest whale species on the planet were systematically hunted, which probably reduced abundance by more than 70% in many cases,” Nicholas Pyenson, a study author and curator of fossil marine mammals at the Smithsonian Institution, told Insider.

“99% of the blue whales that were alive in 1900 were gone in 1960,” he said.

Scientists in the 1970s had assumed that without the whales preying on them, populations of krill and fish would explode, and other predators would thrive once they filled the gap in the food chain.

But that’s not what happened. The ecosystem never returned.

“In fact, there was an incredible drop [of krill] over the next 50 years – and it still happens today, “said Matthew Savoca, lead author of the study and a postdoctoral fellow at Stanford Hopkins Marine Station.

“The steepest declines in krill biomass have been seen in areas where most whales were killed,” he told Insider.

The “Krill paradox” had left scientists amazed.

A humpback whale gives birth at the Stellwagen Bank National Marine Sanctuary. Elliott Hazen

Whales sell much more food than previously thought

Until recently, it was extremely difficult to get a sense of how big whales were feeding. They cannot be kept in captivity and they live deep below the water surface.

The researchers who run the study developed sensors that can detect fish and krill when the whale eats them.

These sensors, which are attached to the whales using suction cups as seen in the video below, were used to track 321 baleen whales from seven different species in the southern ocean that surrounds Antarctica.

Using this technology, the researchers found that whales eat three or more times than previously thought.

This means that pre-whale stocks in the Southern Ocean alone would have eaten about 400 million tonnes of krill a year, far more than had been assumed.

It is also twice the total amount of krill left in Antarctica today.

Approaching a blue whale to attach a suction cup mark Elliott Hazen under NOAA / NMFS Permit 16111

This means that whales produce much more of their iron-rich feces, which explains the severity of the environmental damage when they were killed.

“We believe these whales act as important nutrient recyclers in this ecosystem,” Savoca said

As the whales feed and defecate, they redistribute the iron toward the surface of the ocean. It makes the iron available to phytoplankton, small algae that cannot grow without the nutrient.

These, in turn, are eaten by krill, which are eaten by the whales.

Without the whales, much of this iron falls to the bottom of the ocean and effectively leaves the ecosystem.

Because whales appear to be such a key player in the ecosystem, re-establishing the whale population in the Southern Ocean and in other oceans would be beneficial to the marine environment, Pyenson and Savoca said.

“You would see more krill, more whales. You would probably also see, as a consequence of a healthier ecosystem, greater fish yields, penguin populations can increase, there are all sorts of downstream consequences,” Pyenson said.

Whaling today “does not really have that big of an impact on the world’s whale population,” he said, because its scale is very small compared to the past.

But far more whales – hundreds of thousands – are killed by accident by humans, either by being hit by ships or by getting stuck in fishing gear, Pyenson said.

Read the original article regarding Business Insider