From Whales to Walruses, Sea Mammals Are Under Attack—and So Is the Law That Protects Them

The MMPA doesn’t just consider the health of individual species but their value to their habitats too. This is important because marine mammals can play critical roles that affect entire ocean ecosystems, from maintaining kelp forests to contributing to the chemical makeup of the sea itself. For example, in a process known as “the whale pump,” large whales consume nitrogen and other nutrients in the ocean’s depths and release them at the surface through their excrement. In doing so, some of the world’s largest animals are vital to the growth of some of its smallest—phytoplankton, those microscopic creatures that form the very base of the marine food web.

With this more holistic approach to wildlife management, the MMPA banned the harassment, hunting, capturing, and killing of all marine mammals, not just the endangered or threatened species, in U.S. waters. Congress made clear that it was essential to “act conservatively” to avoid harming species that were of enormous ecological, cultural, and economic significance yet were difficult to study and track. 

The act also helps protect mammals in international waters. Specifically, it requires all foreign fisheries doing business with the United States to demonstrate proof of adherence to the same strict standards that domestic fisheries must meet. Unfortunately, the government’s September 2025 findings revealed that many countries lack basic information on the status of their marine mammal populations and possess little reliable bycatch data—prompting NRDC’s latest legal action.

And the proof that these compliance standards matter is swimming all around us. Not a single marine mammal species has gone extinct in U.S. waters in more than 50 years. Species like the humpback whale, whose population numbers plummeted by 95 percent prior to the law, made impressive recoveries. In fact, 9 of their 14 populations were able to come off the federal endangered species list. Others—like the harbor porpoise, northern elephant seal, and Hawaiian monk seal—have rebounded as well. 

Marine mammal recoveries can also spawn comebacks for local economies as tourists flock to coastal towns for events like whale festivals and whale watching tours. Such sightseeing fetches nearly $100 million in Alaska, more than $200 million in the Pacific Northwest, and close to $200 million in Massachusetts each year. 

“This is a law that Americans should take pride in; a legacy of homegrown conservation and true global leadership for more than 50 years,” says Jasny. 

The reauthorization bill touches on nearly every major provision that makes the MMPA such an effective law. One of the most important elements in jeopardy is its “incidental take” provision. 

Industrial activity can kill, injure, disorient, or drive marine mammals from their habitats. So the MMPA requires companies—such as those that use high-powered airguns to look for oil deep beneath the ocean floor—to get a government permit for what the act refers to as an “incidental take” of a marine mammal. 

Under existing law, the government must also recommend measures that achieve “the least practicable adverse impact” on marine mammal populations. Such steps could include avoiding certain breeding grounds, minimizing work during mating season, or using the latest technologies for quieter operations. If passed, however, the reauthorization bill would prevent wildlife agencies from changing the timing, location, or design of industrial activities in any way.

And that’s just the start. The MMPA requires companies to obtain incidental take permits every five years, at least. This allows regulators to reassess a company’s operations, making sure they are up-to-date in a changing ocean. But with the reauthorization bill, these permits would never expire, and they would also no longer limit the harm to only small numbers of marine mammals. And at a time when the Trump administration has radically downsized environmental budgets and staff, the bill would rubber-stamp permit applications if the wildlife agencies miss an artificially tight deadline.

Another area that the bill targets is the MMPA’s approach to wildlife data, which is quite challenging to collect when it comes to marine mammals. Just think how difficult it would be to get an exact count for a species that migrates across entire oceans or to know every time a whale is struck by a ship or entangled in a net somewhere out at sea. For example, more than two decades passed before experts could conclusively prove that tropical dolphins were in trouble due to tuna fishing, despite the death of hundreds of thousands every year. That’s why the current MMPA doesn’t base its preventative actions on information that’s impossible or impractical to obtain. 

The reauthorization bill would do the opposite by setting standards for scientific information that can’t be met. For example, the bill would require “systematic and complete abundance survey data”—something that’s just not feasible for many populations—before wildlife agencies could limit the number of marine mammals that may be lost each year. And for a population’s official mortality count, the bill would only consider deaths that are directly observed and documented, as if the body of every marine mammal in the ocean could be accounted for. 

“This would set a very, very high bar for any kind of protective action to be taken at all—an extremely high burden of proof,” Jasny says. He points to the endangered North Atlantic right whale as one of the best tracked species, and one for which there’s no question that action is needed. “Yet under these very clever technical changes, even right whales are unlikely to qualify for any kind of conservation help.” 

Some of the proposed changes would also prevent the government from taking actions under the Endangered Species Act to protect imperiled marine mammals. Tellingly, the bill would downgrade the MMPA’s focus on species’ “recovery” to mere “survival”—the lowest possible bar before extinction.

Should the bill pass, there would be a lot less oversight on industrial activities in U.S. waters. The oil and gas industry, for one, would be very happy, since it has been pushing for some of these changes for years. After all, offshore oil and gas development poses many threats to marine mammals, including everything from seismic blasting—which disrupts their communication, navigation, hunting, and mating—to catastrophes like the BP disaster that smother them in oil.

The bill would pave the way for the Trump administration’s plan to massively expand offshore oil and gas exploration in California, the eastern Gulf of Mexico, and much of Alaska at enormous costs to marine mammal populations. And with U.S. seafood consumption increasing steadily over the last three decades, now is certainly not the time to go lax on efforts to prevent deadly entanglements of whales, dolphins, and other species.

The bill must still pass both the House and Senate, “but we’ve seen time and time again unprecedented attacks on wildlife and marine mammals from this Congress,” says Jasny. The good news is that “there is plenty of pushback from the conservation community, from Tribal authorities, from the scientific community, from aquariums.” Hopefully, that resistance coupled with the latest legal battle will be enough to buy these important ocean players, and their ecosystems, more time.