Whales are revered as great mammals of the oceans, majestically traversing the vast marine environment in awe-inspiring fashion. However, little ecological importance was placed on the mammals; over-harvesting whales became common practice over the years. Now, scientists from the University of Vermont have conducted a study that reveals whales are the great engineers and curators of the deep, placing a new emphasis on the urgency of saving the mammals of the ocean.
Baleen and sperm whales, known collectively as the “great whales,” include the largest animals to have ever lived on Earth. With huge metabolic demands, great whales are the ocean’s ecosystem engineers: they eat many fish and invertebrates, 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”.
“Among their many ecological roles, whales recycle nutrients and enhance primary productivity in areas where they feed,” said Joe Roman, biologist at the University of Vermont. Whales do this by feeding at depth and releasing fecal plumes near the surface — which supports plankton growth — a remarkable process described as a “whale pump.” Whales also move nutrients thousands of miles from productive feeding areas at high latitudes to calving areas at lower latitudes.
“As humpbacks, gray whales, sperm whales and other cetaceans recover from centuries of over hunting, we are beginning to see that they also play an important role in the ocean,” Roman said.
Sometimes, commercial fishermen have seen whales as competition. Yet this new paper summarizes a strong body of evidence that indicates the opposite can be true: whale recovery “could lead to higher rates of productivity in locations where whales aggregate to feed and give birth,” supporting more robust fisheries.
Such interdependency between whales and the ecosystem highlight the conservation efforts that need to be undertaken to support sustainable environments throughout the 21st century.