Scientists and fisheries managers have long underestimated the valuable role large whales play in healthy ocean ecosystems, a new study suggests. And, scientists add, those commercial fishermen who complain that whales steal fish from their nets have it wrong.

An increase in the number of large whales—like blue, sperm, right, and gray—around the world could lead to a healthier ocean and more fish, a team of scientists report in a review study published this month in the journal Frontiers in Ecology and the Environment.

The underestimation occurred because "when oceanographic studies were started, large whales were largely absent from the ecosystem—because we had killed most of them," says the study's lead author, Joe Roman, a biologist at the University of