Whales do more than simply glide through the ocean—they play a vital role in sustaining tropical ecosystems. While scientists have long understood that whales transport nutrients from deep waters to the surface, new research reveals that they carry these nutrients across vast distances, from Alaska to Hawaii, fertilizing tropical waters that support diverse marine life.
Whales stimulate plankton growth by feeding in deep waters and releasing waste at the surface, and new findings published March 10 in Nature Communications build on this research, showing how they carry nutrients across vast distances, from Alaska to Hawaii, enriching tropical waters that support marine life.
Thousands of humpback whales migrate yearly from the Gulf of Alaska to Hawaii, where they breed. Their waste, shed skin, and even afterbirth introduce vital nutrients to coastal waters. According to the study, in the Hawaiian Islands Humpback Whale National Marine Sanctuary, whales contribute twice as many nutrients as the ocean’s natural currents.
“We call it the ‘great whale conveyor belt,” Joe Roman, a biologist at the University of Vermont, explains that whales gather nutrients over vast feeding areas but deposit them in smaller breeding zones. These concentrated inputs help sustain marine life in regions where nutrients are scarce.
Newborn whales, at first, lack the energy to travel long distances. Researchers believe this is one reason mothers stay in shallow waters, where their calls are muffled from predators, such as killer whales. “Moms and newborns are calling all the time, staying in communication,” Roman said. “And they don’t want predators, like killer whales or breeding humpback males, to pick up on that.”
Baleen whales feed in the summer in nutrient-rich waters near Alaska, Iceland, and Antarctica. They consume large amounts of krill and fish, gaining up to 30 pounds daily. This energy sustains them on their long winter migrations, during which they stop eating altogether.
Gray whales travel nearly 7,000 miles from Russia to Baja California, while humpbacks in the Southern Hemisphere migrate more than 5,000 miles from Antarctica to Costa Rica. Along the way, they burn about 200 pounds of fat daily while releasing nitrogen-rich waste, further enriching marine ecosystems.
Before the 19th century, whales likely played an even greater role in ocean health. “Because of their size, whales can do things that no other animal does. They’re living life on a different scale,” said Andrew Pershing, an oceanographer at Climate Central and a co-author of the study. However, one major factor remains unknown—blue whales.
Blue whales, the largest animals alive, were not included in the study’s estimates due to a lack of data. Their populations remain low following intense whaling in the 20th century. “There are basic things that we don’t know about them, like where their breeding areas are,” Pershing said.
While humpbacks and some other whale species are recovering, researchers say the loss of millions of whales over centuries has significantly reduced the amount of nutrients cycling through the ocean.
Scientists compare the role of whales to a planet-wide circulatory system. “For their part, animals play an important role in moving nutrients. Seabirds transport nitrogen and phosphorus from the ocean to the land in their poop, increasing the density of plants on islands. Animals form the planet’s circulatory system—and whales are the extreme example.” Roman said.
As researchers continue studying whale populations, they emphasize that protecting these animals is critical not just for their survival but also for the overall health of the ocean.
