What lies beneath the deep, dark expanse of the ocean is something that has fascinated sailors, fishermen, adventurers, poets and explorers for centuries. How could residents of New England, for instance, have known that beneath the coastal waters lies a chain of extinct undersea volcanoes and canyons as deep as the Grand Canyon and mountains as high as any found east of the Rockies, harboring rare and endangered whales, sea turtles and fishes and coral as old as the Redwoods?

We have glimpsed this and other worlds beneath the waves thanks to advances in science and technology. Ocean-going ships and submarines provide a window into the deep. In shallower and warmer seas, scuba-diving scientists have documented a similarly breathtaking, but previously unappreciated, diversity of life. We’ve discovered an unimaginable underwater world. Strange life forms. Unique species. Mysteries waiting to be solved.

But technology also allows us to access, disturb and eliminate these special places, putting them, and often ourselves, at risk. A single pass of a fishing trawler or mining gear can destroy centuries-old species and habitats, including nursery grounds for important fisheries.

Fortunately, governments are increasing the number of marine protected areas, or MPAs, in the ocean. Areas categorized as MPAs mean that something inside is protected, although often not much. However, two MPA subcategories are essential to achieving the goals of protecting ocean ecosystems, improving resilience in the face of multiple environmental changes and providing benefits for both nature and people.

“Fully protected areas” mean no extractive activities are allowed, while “strongly protected areas” mean no commercial and only minimal recreational extractive activities are allowed. The vast majority of MPAs do not fall into either of these two categories and are called “partially protected.” In addition to area-based protection, we also need to reduce greenhouse gas emissions and pollution, and to sustainably manage fisheries.

As ocean scientists, we are encouraged that multiple governments are now taking action to protect special places in the ocean, but we believe science-driven action for ocean conservation must be greatly accelerated.

Global trend in MPAs

President Obama has taken a leadership role in ocean protection by increasing more than four-fold the amount of “strongly protected” ocean area under U.S. jurisdiction (from 5 percent to over 23 percent). He did this through the creation or expansion of three marine monuments, including the only marine monument in the U.S. Atlantic – the Northeast Canyons and Seamounts Marine National Monument, created in September 2016. Nearly the size of Connecticut, this new designation encompasses many of the unique canyons, seamounts and species in the deep New England waters.

A few weeks earlier, the president created the largest strongly protected area on the planet – on land or at sea – by expanding Papahānamokuākea Marine National Monument to 1.5 million square kilometers (580,000 square miles) – twice the size of Texas. The U.S. now far exceeds any other nation in the total area of the ocean it strongly protects.

The global picture is also changing rapidly. For decades, strongly protected areas of the ocean hovered at less than 0.1 percent. In the last decade, there has been a surge in protection, resulting in now 3.5 percent of the ocean in MPAs, 1.6 percent of which is strongly protected. The international community has also set a global target of 10 percent ocean protection in MPAs by 2020.

Until very recently, almost all of this protection was in the “Exclusive Economic Zones” (EEZs) of individual countries – the area over which each country has jurisdiction. In a globally significant development at the end of October 2016, the Commission on the Conservation of Antarctic Living Marine Resources announced its unanimous decision to create the Ross Sea MPA. At 1.55 million square kilometers, this is now the largest protected area in the world, although the portion fully protected from any extractive activities (1.17 million square kilometers) is slightly smaller than Papahānamokuākea.

The creation of the Ross Sea MPA is significant for many reasons. It’s large (bigger than France, Germany and Spain combined); it’s the first large-scale protected area in the high seas (beyond the EEZs of individual countries); and it was created through the joint efforts of 25 governments. Once the MPA is implemented, the percent of the global ocean that is strongly protected will jump to 2.6 percent – an impressive increase from a decade ago but still far short of global targets.

This action parallels a new willingness to focus on conservation and sustainable use of the ocean at the United Nations. One of the 17 Sustainable Development Goals that frame the international agenda for the next 15 years focuses squarely on the ocean. In addition, negotiations are underway at the U.N. about a possible treaty to protect the biodiversity of the high seas, which represent two-thirds of the global ocean.

Results of MPAs

The need for more and greater ocean protection is strongly supported by scientific information.

The benefits of establishing well-designed and enforced fully protected MPAs are well-documented. On average, fully protected areas can increase the total biomass of marine life by more than 400 percent. Fishes and invertebrates like clams and lobsters tend to grow larger and produce many more young. Partially protected areas can provide some benefits, but much less than those in strongly protected areas. The increases in number and size of individual organisms, and the number of species and offspring per individual inside fully protected areas, are substantial.

An equally important benefit of fully or strongly protected areas may be their ability to provide greater resistance to environmental changes and their ability to recover more rapidly from environmental changes. For example, when a low-oxygen event in the Gulf of California killed many abalones and threatened the local fishery, the abalones in the marine reserve were the first to recover and begin to replenish the region. When creating strongly protected monuments, President Obama explicitly linked conservation action with climate resilience.

No one knows the full impact of climate change on ocean ecosystems, but it is logical to assume that restoring to health or protecting healthy marine communities inside strongly to fully protected areas is likely to be one of the best bets for enhancing the resilience of ocean ecosystems for the future.

Impact on fisheries

Research also shows that abundant fish and invertebrates inside fully protected MPAs can spill over into fished areas outside. The Mediterranean region has pioneered the concept of the buffer zone, where a fully protected core area is surrounded by a sustainably fished, partially protected area.

This combination of MPAs and effective fisheries management has led to higher catches in the Mediterranean. But the benefits to fisheries from MPAs have also been seen in areas around the world for both small-scale and larger-scale fisheries outside their borders.

An exciting recent innovation includes the coupling of fully protected MPAs with a fishery management approach that gives fishermen or communities secure access to places to fish. The outcome is that small-scale fisheries are more likely to be sustainable and profitable.

Although restricting access to some areas at sea can shift fishing effort elsewhere, both experience and theory demonstrate that recoveries within strongly protected areas can more than offset losses. Nonetheless, greater effort to employ strategies that are known to effectively offset short-term costs is needed to achieve long-term benefits.

More to explore

Despite the significant progress made in protected areas the last decade, huge challenges remain to achieve the goal of a healthy ocean. Accelerating ocean protection will require continued political will and accountability, monitoring and enforcement of existing areas, and identification of new areas for protection. In parallel, fishery reforms, reduction of plastic, nutrient and chemical pollution, and significant reduction of greenhouse gases are all needed.

It is useful to remember that for most of its history, the ocean was a de facto fully protected area, simply because humans could not access it. It is only in the last half-century that most of the ocean has become accessible to extractive activities. Industrial-scale fishing, for example, is now global, leaving only small fractions of the ocean free from extractive activity.

The ocean supports the well-being of 870 million people who depend directly on the ocean for food and livelihoods. Effective fishery management is urgently needed but must be complemented with parallel efforts to protect more area from all extractive activities.

Suggesting that fixing fishery management alone will suffice assumes that the ocean is valued only for its fisheries. It denies the equally valid perspective that life in the ocean is valued in and of itself, apart from any utilitarian value it has for humans. Moreover, having some nonfished areas can provide insurance against accidental mismanagement or environmental changes. And nonfished areas provide useful controls to evaluate impacts of fishing.

Especially in times of uncertainty, a portfolio of approaches makes good common sense. We should strive to ensure that enough of what lies beneath is protected and preserved for future generations to discover, use and sustain.