Here’s how much a blue whale eats in one year

By Mark Waghorn via SWNS

The blue whale eats TWO MILLION TONS of prey a year, according to new research.

It is the largest animal that ever lived - and has an appetite that more than matches its size, say scientists.

The creature sucks up tiny krill by filtering seawater through plates of frayed, bristle-like combs in its huge jaws.

Now a study has found baleen whales - which also include fin and humpbacks - eat three times more food than previously believed.

A blue whale can reach up to 110 feet in length and weigh over 200 tons - as big as a passenger jet. It eats almost a third of its body mass - a day.

And the vast amounts of poop is helping to save the planet - by reducing global warming.

The discovery could boost conservation efforts to save the endangered behemoths, say scientists.

Co-author Dr. Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian's National Museum of Natural History, Washington DC, explained: "Our results say if we restore whale populations to pre-whaling levels seen at the beginning of the 20th century, we'll restore a huge amount of lost function to ocean ecosystems.

"It may take a few decades to see the benefit, but it's the clearest read yet about the massive role of large whales on our planet."

In the Southern Ocean near Antarctica, before the whaling era, the krill biomass they consumed is estimated to have been 430 million tonnes annually - substantially greater than today's entire world fish catch.

Intense fishing has since decimated ocean stocks. But whale feeding seems to be sustainable, as evidenced by their long lifespan and high degree of specialization geared to just one prey - krill.

The US team tagged 321 baleen whales from seven species in the Atlantic, Pacific and Southern oceans - tracking daily foraging behavior and prey consumption.

They were found to consume a daily average of between five and 30 percent of their body mass - across all species and regions studied.

For example, populations of blue, fin and humpback whales in the California Current Ecosystem each require more than two million tonnes of krill every year.

It means the undersea giants are vital to ocean health and productivity - as they also pump out more waste.

It keeps key nutrients suspended close to the surface where they power blooms of carbon-absorbing phytoplankton - the basis of their food-web.

Without whales, those nutrients more readily sink to the seafloor - limiting the capacity of ocean ecosystems to absorb greenhouse gases.

Lead author Dr. Matthew Savoca, a marine ecologist at Stanford University, California, likened the tags suction-cupped to the whales' backs to a miniature smartphone.

They were fitted with a camera, microphone, GPS and an accelerometer to monitor movements in three-dimensional space.

The data set also included drone photographs of 105 whales to measure their respective lengths.

Each animal’s length could then be used to create accurate estimates of its body mass and the volume of water it filtered with each mouthful.

Finally, members of the team involved in this near-decade-long data collection effort used small boats equipped with echo-sounders to race to sites where whales were feeding.

The echo-sounders use sound waves to detect and measure the size and density of swarms of krill and other prey species.

This step was crucial empirical grounding for the team’s estimates of just how much food the whales might be consuming.

Three lines of evidence were combined - how often whales were feeding, how much prey they could potentially consume while feeding and how much prey was available.

The researchers could generate the most accurate estimates to date of how much these gargantuan mammals eat each day and, by extension, each year.

For example, the study found an adult eastern North Pacific blue whale likely consumes 16 metric tons of krill per day during its foraging season.

A North Atlantic right whale eats about five metric tons of small zooplankton daily and a bowhead whale puts down roughly six metric tons of small zooplankton per day.

When there were a lot more whales chowing down on krill, there must have been a lot more krill for them to eat.

The decline of numbers following the loss of so many of their biggest predators is known as 'the krill paradox.'

It is most pronounced in areas where whaling was especially intense, such as the Scotia Sea between the Southern Ocean and the Atlantic Ocean southeast of South America.

Dr. Savoca said: "This decline makes no sense until you consider whales are acting as mobile krill processing plants.

"These are animals the size of a Boeing 737, eating and pooping far from land in a system that is iron-limited in many places.

"These whales were seeding productivity out in the open Southern Ocean and there was very little to recycle this fertilizer once whales were gone."

The study in Nature suggests restoring whale populations could also boost the amount of carbon dioxide sucked up by the phytoplankton - which are eaten by krill.

It is estimated the nutrient cycling services provided by pre-whaling populations at the start of the 20th century might fuel a roughly 11% increase in marine productivity in the Southern Ocean.

It would also draw down at least 215 million metric tons of carbon, absorbed and stored in ocean ecosystems and organisms in the process of rebuilding.

It is also possible these carbon reduction benefits would accrue year over year.

Indeed, the findings suggest in the Southern Ocean, for example, baleen whales recycled 12,000 tonnes of iron per year before whaling, compared to 1,200 tonnes per year today.

Dr. Pyenson added: "Our results suggest the contribution of whales to global productivity and carbon removal was probably on par with the forest ecosystems of entire continents, in terms of scale.

"That system is still there, and helping whales recover could restore lost ecosystem functioning and provide a natural climate solution."