Still, humpbacks face some substantial challenges. They can get tangled in fishing nets, or struck and killed by ships. Of the 14 global populations identified by U.S. officials, four are endangered and one is threatened—and all five of those live in the northern hemisphere. Currently, the National Marine Fisheries Service is proposing to protect large areas of habitat coastal waters off the coasts of Alaska, Washington, Oregon, and California to reduce these impacts. The agency is accepting comments on the proposal through December 9.
Today's humpbacks also live in an altered marine environment. The singing cetaceans spend much of their year feeding in rapidly warming Antarctic waters. One study estimated that krill, the tiny crustaceans humpbacks feed on, have had their habitat drift almost 300 miles southward as water temperatures have gone up. And there's only so much room to go poleward, so this shift could spell a loss of the primary food source in these cold waters. Zerbini says its important to keep an eye on the ecosystem, to see how the increased numbers of humpbacks interact with other organisms, including the seals and penguins that also eat krill.