Whales as the Ocean's Main Ecosystem Engineers

Whales, though impressive mammals, until now were thought to be inconsequential in terms of their role in Earth's oceans. But new research from the University of Vermont has revealed that these massive creatures make a huge difference, and in fact are the ocean's main ecological engineers.

"For a long time, whales have been considered too rare to make much of a difference in the oceans," conservation biologist Joe Roman noted in a news release.

But that assumption was a mistake according to researchers. Whale populations in the past were decimated, declining at least 66 percent and possibly as high as 90 percent, but as they recover their vital role in the world's oceans becomes clear.

"The continued recovery of great whales may help to buffer marine ecosystems from destabilizing stresses," the research team wrote. And with climate change causing rising temperatures and acidification that threaten ocean ecosystems, whales will likely play a very important part in the future. "As long-lived species, they enhance the predictability and stability of marine ecosystems," Roman added.

Whales not only have a powerful and positive influence on the function of oceans, but they also impact global carbon storage and the health of commercial fisheries.

Baleen and sperm whales, known collectively as the "great whales," include the largest animals ever to inhabit the Earth. With huge metabolic demands - and large populations, that is before humans started hunting them - they have become the ocean's main ecological engineers. They eat many fish and invertebrates, are themselves prey to other predators, like killer whales, and distribute nutrients through the water. Even their carcasses, dropping to the seafloor, provide habitat for many species that only exist on these "whale falls."

Unfortunately for these naturally valuable mammals, commercial fisherman have found them valuable in other ways, and whaling significantly reduced their numbers.

"The decline in great whale numbers... has likely altered the structure and function of the oceans," Roman said, "but recovery is possible and in many cases is already underway."

Previous studies had investigated smaller organisms, which, though important, "are not the whole story," Roman said.

The findings were published in the journal Frontiers in Ecology and the Environment.