The first study to methodically calculate how much food blue whales and some of their close relatives eat has yielded a simple answer: a whole lot.
The blue whale, the largest animal in Earth’s history, eats about 16 tonnes of krill daily in the North Pacific, gobbling up these tiny shrimp-like crustaceans with a filter-feeding system in their mouths using baleen plates made of keratin, the substance found in people’s fingernails, scientists said on Wednesday.
“That is roughly the weight of one fully loaded school bus,” said study coauthor Nick Pyenson, curator of fossil marine mammals at the Smithsonian Institution’s National Museum of Natural History in Washington.
Photo: AFP / Stanford University
The researchers calculated daily food intake for seven baleen whale species, tracking 321 individual whales in the Atlantic, Pacific and Southern Oceans from 2010 to 2019. These gigantic marine mammals were found to eat up to three times more food than previous estimates that were based on stomach contents of hunted whales or extrapolations from smaller marine mammals.
The other species studied — humpback, fin, bowhead, right, Antarctic minke and Bryde’s whales — also devoured impressive amounts. North Pacific Humpback whales can eat 9 tonnes of krill daily, while fin whales consume 8 tonnes.
“It is an unimaginable amount of food, but large whales are themselves unimaginable. A blue whale is the size and weight of a Boeing 737,” said Stanford University marine biologist Matthew Savoca, who is lead author of the study published in the journal Nature.
Blue whales, larger than even the biggest dinosaurs, can reach 33m long and 200 tonnes.
The researchers determined how often each whale engaged in feeding behavior using electronic tag devices suction-cupped to the animal’s back, with a camera, microphone, GPS locator and an instrument that tracks movement. Drones were used to estimate the size of a whale’s mouth area and how much prey it could engulf. An acoustic method measured nearby prey biomass.
Baleen whales eat zooplankton: small prey including krill, fish or crustaceans called copepods. The largest species prefer krill. Smaller species such as humpback, Bryde’s or minke whales can eat schooling fish or krill.
Most baleen whales do not eat year-round, having a feast-or-famine annual cycle. They eat about 100 days annually, typically during a summer breeding season, while eating little the rest of the year. Based on eating 16 tonnes in a day, the blue whale would consume perhaps 1,600 tonnes annually.
Food intake varied based on species, location and prey type. Among three humpback populations studied, North Pacific krill specialists consumed 9 tonnes daily, North Pacific fish eaters 3.5 tonnes and Southern Ocean krill specialists 3 tonnes daily.
Among the other species, Arctic bowhead whales consumed 6 tonnes daily of copepods, North Atlantic right whales 5 tonnes of copepods, South Atlantic Bryde’s 1 tonne of fish and Southern Ocean minke 0.69 tonnes of krill.
As the whales eat more than previously known, they also produce more excrement, an important ocean nutrient source. By catching prey and defecating, they help keep nutrients suspended near the sea surface to generate blooms of carbon-absorbing microscopic organisms called phytoplankton that form the base of marine food webs.
Pyenson said the study’s calculations suggest that before baleen whale numbers were dramatically reduced by 20th century industrial whaling, they had consumed more food than all of the world’s current krill biomass and global fisheries combined.
“The implication of these numbers is that whales supported far more productive ocean ecosystems before whaling, and that promoting whale recovery in the 21st century may restore ecosystem functions lost in the past hundred years,” Pyenson added.
IDENTITY: A sex extortion scandal involving Thai monks has deeply shaken public trust in the clergy, with 11 monks implicated in financial misconduct Reverence for the saffron-robed Buddhist monkhood is deeply woven into Thai society, but a sex extortion scandal has besmirched the clergy and left the devout questioning their faith. Thai police this week arrested a woman accused of bedding at least 11 monks in breach of their vows of celibacy, before blackmailing them with thousands of secretly taken photos of their trysts. The monks are said to have paid nearly US$12 million, funneled out of their monasteries, funded by donations from laypeople hoping to increase their merit and prospects for reincarnation. The scandal provoked outrage over hypocrisy in the monkhood, concern that their status
The United States Federal Communications Commission said on Wednesday it plans to adopt rules to bar companies from connecting undersea submarine communication cables to the US that include Chinese technology or equipment. “We have seen submarine cable infrastructure threatened in recent years by foreign adversaries, like China,” FCC Chair Brendan Carr said in a statement. “We are therefore taking action here to guard our submarine cables against foreign adversary ownership, and access as well as cyber and physical threats.” The United States has for years expressed concerns about China’s role in handling network traffic and the potential for espionage. The U.S. has
A disillusioned Japanese electorate feeling the economic pinch goes to the polls today, as a right-wing party promoting a “Japanese first” agenda gains popularity, with fears over foreigners becoming a major election issue. Birthed on YouTube during the COVID-19 pandemic, spreading conspiracy theories about vaccinations and a cabal of global elites, the Sanseito Party has widened its appeal ahead of today’s upper house vote — railing against immigration and dragging rhetoric that was once confined to Japan’s political fringes into the mainstream. Polls show the party might only secure 10 to 15 of the 125 seats up for grabs, but it is
The US Department of Education on Tuesday said it opened a foreign funding investigation into the University of Michigan (UM) while alleging it found “inaccurate and incomplete disclosures” in a review of the university’s foreign reports, after two Chinese scientists linked to the school were separately charged with smuggling biological materials into the US. As part of the investigation, the department asked the university to share, within 30 days, tax records related to foreign funding, a list of foreign gifts, grants and contracts with any foreign source, and other documents, the department said in a statement and in a letter to
RSS