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A Message from Richard Merrick, Chief Science Advisor for NOAA Fisheries

The MMPA In Action


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Forty Years of Marine Mammal Protection: What’s Worked, and What’s Next?
October 2012 

Forty years ago, the future of many marine mammal species seemed uncertain. Dolphins had been dying in the Eastern Tropical Pacific tuna fishery since the fishery began in the late 1950s, with an estimated 6 million animals killed. Close to 2 million whales had been killed in commercial whaling during the 20th century, with many of the world’s species of whales hunted nearly to extinction. Then, in October of 1972—forty years ago this month—Congress passed the Marine Mammal Protection Act, also called the MMPA. For many species, this visionary environmental law turned the tide.

Today, most whale species in U.S. waters are recovering, with gray whales fully recovered. Only about 1,000 dolphins die in tuna nets in the Eastern Tropical Pacific each year—a reduction in annual mortality of more than ninety-nine percent. Working with our partners, we have protected marine mammals in U.S. waters from death and injury, rebuilt many formerly depleted populations, and conducted ground-breaking scientific research.

On the other hand, many marine mammal species remain depleted worldwide. Some foreign fishing fleets continue to use fishing gear that captures and harms dolphins and seals. And new environmental issues are emerging—notably rising levels of ocean noise, climate change, and ocean acidification—that pose challenges on a scale unforeseen in 1972. So, while the Act has successfully addressed the threats from 40 years ago, we must now apply it in a new and fast changing world, and as opportunities arise, expand our efforts internationally.

What the Act Requires

The Act prohibits, with limited exceptions, the “taking” of marine mammals—that is, killing, capturing, or harassing them—and it requires action to rebuild depleted populations. Marine mammals, the Act declared, “should not be permitted to diminish beyond the point at which they cease to be a significant functioning element of the ecosystems of which they are a part.” In articulating this vision of intact ecosystems, the Act was ahead of its time and helped give rise to the new ecosystem-based approach to resource management that we strive for today.

Why the Act Has Been Successful 

The MMPA has been successful in part because it has evolved over time to meet the changing nature of the challenge. The 1994 amendments to the Act, for instance, required regular assessments of population size and fishery bycatch—that is, incidental death or injury as a result of fishing— for all marine mammal stocks in U.S. waters.  It also created “take reduction teams.” Comprised of scientists, conservationists, and fishing industry representatives, these teams have greatly reduced the number of marine mammals killed or injured by fishing vessels under U.S. jurisdiction each year.

The language of the Act has also proved flexible enough to encompass newly emerging threats. Although it was not fully appreciated in 1972, sonar, seismic surveys, and other high-energy acoustic events can cause stress, injury, and in some cases fatal strandings of marine mammals. Today, using the MMPA, we work to reduce the impact that these activities have on marine mammals.

Finally, the Act has been effective because it is part of a legal framework that is much greater than the sum of its parts. Applying the Act alongside the Endangered Species Act, as well as international conventions for marine mammal protection, is fundamental to the conservation of these species.

As we continue our work to protect marine mammals and the ecosystems they inhabit, it is worth remembering that our success to date derives in part from these features of the law—that it evolves to meet new challenges and that it exists as part of a larger legal framework for environmental protection. Going forward, our application of the Act must continue to exhibit these traits if it is to remain effective in addressing new challenges.

We Must Improve International Cooperation 

The MMPA has successfully addressed many of the threats from 40 years ago. But we cannot successfully protect these species on our own. Although fishing-related mortality of marine mammals in U.S. waters and on U.S. vessels on the high seas is now monitored and being brought under control, it is still a significant threat in other parts of the world. Although some populations of marine mammals have been rebuilt, many others remain depleted. The International Union for the Conservation of Nature currently lists 25 percent of marine mammal species worldwide as vulnerable to extinction. Many of these species spend part of their lives in U.S. waters, and effective international cooperation is essential to their conservation.

We Will Use Ecosystem Approaches to Management 

The MMPA was designed mainly to deal with discrete hazards, such as bycatch or noise events that can be traced back to a specific source. The greater threats to marine mammals today, most importantly rising levels of anthropogenic sound, climate change, and ocean acidification, may be more complex and difficult to deal with than the problems of an earlier age.

The Act does offer a hint of how we might proceed in the face of these challenges, however. The MMPA explicitly aspires to a world of intact ecosystems, and we can undertake to make this vision a reality by using ecosystem approaches to management. That means planning for environmental variability, and keeping the big picture in mind.

We are already seeing profound changes in ocean conditions associated with rising temperatures. In the Gulf of Maine for instance, the distribution and abundance of zooplankton is shifting in ways that will impact species up the food chain, including endangered Atlantic right whales. Similar changes are occurring throughout the oceans, and we must monitor and predict these changes so that we can adapt to them quickly.

With this in mind, NOAA Fisheries scientists are working to develop the next generation of ocean observation systems. We are estimating whale abundance by listening for them with seafloor-mounted microphones and using aerial drones to survey in places where manned flights are expensive and dangerous. These systems will allow us to more cost-effectively and accurately complete the stock assessments that the MMPA requires. On a more fundamental ecosystem level, we are deploying a network of autonomous sensors to record the vital signs of the ocean and report them back in real time.

Increased awareness of what’s going on in the oceans will allow us to manage adaptively in the face of a changing climate and also to manage with the big picture in mind. In addition to protecting individual species, we must manage for the many inter-relationships between species, human activities, and the larger environment. Such an ecosystem approach to management is key to fulfilling the vision of the MMPA, and we are quickly developing the scientific and technical capabilities to make this possible.

We Will Continue the Work We Have Started

Today, the oceans are a very different place than they were 40 years ago. Thanks to the MMPA, many of the threats that marine mammals faced in that earlier age are being brought under control. Still, many species remain depleted, and a new and complex set of challenges has emerged. We will continue to work with our national and international partners, and to develop new technologies and approaches to management, to insure that the Act remains effective in a globalized and fast-changing world.


Richard L. Merrick, Ph.D.
Director, Scientific Programs and Chief Science Advisor