You can recover the marine ecosystem by helping out whales in the first place.
Recent studies have found out that whales like fin, blue and humpback, eat quite more than what scientists had earlier estimated. They almost eat 3 times more than what was expected. Since, these mammals are eating more than expected, that only means one thing.
They must be pooping more than that was estimated.
Scientists had underestimated the amount of food and excrement taken or spewed out by the whales. They have also not realized how important these mammals are to the entire ecosystem’s health.
“It’s a remarkable fact that we live alongside the largest vertebrates to have lived on the planet—the largest baleen whales are heavier than the largest dinosaurs. We’re living in a time of giants, and we hardly know them!” stated co-author Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian’s National Museum of Natural History.
He believes that they do not know the answer to the most basic questions of how much food do these whales eat, where they move to and how do they produce their offspring. They used real-world data on baleen whale feedings and excretions to find out the exact amount of food consumed by baleen whales, before the 20th-century whaling.
The estimates made in the past about the food consumption of these mammals were merely guesses. They made guesses from the prey yields in stomach contents or extrapolated data from smaller marine mammals.
These are both poor analogs.
Real-Time Tracking These Whales
Scientists used data from 321 whales of around 7 species living in the Pacific, Atlantic, and Southern Oceans. The information that they collected was from 2010 to 2019.
Each of these tags was attached to a whale’s back with a suction cup and consisted of a GPS, mic, camera, and an accelerometer to track their movements. The information gathered from these devices helped the researchers understand how these massive mammals were feeding.
The scientists went to feeding sites too. They also analyzed 105 photographs of whales from 7 species and measured their lengths. They used this information to calculate their body mass and the volume of water filtered with every mouthful.
“These three lines of data were all used to calculate daily consumption for each species of whale using real-world numbers,” Pyenson says. These results were later published in the Nature journal.
Employing Ecosystem Engineers
A study, back in 2008, estimated that most whales in the California Current ecosystem in the northeastern Pacific Ocean, need about 2 million metric tons of fish, krill, and other food each year. The new study proved that fin, blue, and humpback whales living in the same region each needed more than 2 million tons of food in a year.
The study found that an adult eastern North Pacific blue whale likely eats 16 metric tons of krill daily during foraging season, while a bowhead whale eats about 6 metric tons of zooplankton per day, and a North Atlantic right whale eats roughly 5 metric tons of zooplankton daily.
Whales tend to excrete near the surface of the water. The nutrients in these excrements power phytoplanktons by staying close to the water’s surface. The phytoplanktons absorb carbon dioxide (greenhouse gas) and play a crucial role in the marine food chain.
“Our results illuminate something that scientists had suspected for the largest whales, but hadn’t yet carefully quantified: the scale of their role as ecosystem engineers,” Pyenson says. “If we promote the recovery of these giants, we think that would be a good thing for the health and function of the world’s oceans—and good for our own descendants too!”
The calculations suggested that baleen whales consumed more food than all of the world’s krill biomass and fisheries combined before they were reduced in large numbers by whaling activities.
“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.”