Size Matters: The Case for Large Ocean Reserves

Our oceans contain most of Earth's biodiversity, yet only a tiny fraction is protected. Overfishing, pollution and climate change threaten to degrade the special places in our oceans that remain healthy and teeming with life. Large, no-take marine reserves—comparable to large national parks on land—can benefit a broad array of species and critical habitats.

On May 15th, Jay Nelson, director of the Pew Environment Group's Global Ocean Legacy project, will speak about the project as part of the panel "Size Matters: The Case for Large Ocean Reserves." Alistair Gammell, Global Ocean Legacy's UK director, will speak on this panel about the designation of the Chagos Marine Reserve, the largest no-take marine reserve in the world. Here, Jay Nelson answers why large, no-take marine reserves are so crucial to ocean conservation.

Why are large no-take marine reserves important for ocean conservation?

Imagine if Yellowstone National Park in the United States, South Africa's Kruger National Park or the many other significant protected areas that followed in their path did not exist today. What would these special places look like? We need to apply this thinking to our oceans. Just like our lands, our oceans are vast, fragile places teeming with life that require a variety of protective approaches. No-take marine reserves provide a critical took in ocean conservation.

Why does size matter when it comes to marine reserves?

Small marine protected areas near coastlines are very important for improving the way local communities sustainably use ocean resources for food and livelihoods. However, small areas are not the only way to ensure healthy oceans. It is widely recognized that permanently protected, very large, no-take marine reserves are also an essential tool to protect wide-ranging and migratory species, preserve unique biological and geological features, sustain biodiversity and maintain flourishing natural populations of marine life for future research. When such reserves are established, a sufficient expanse of ocean protects habitat and provides refuge for species such as tuna, sharks, seabirds, turtles and marine mammals.

What are the unique benefits of large no-take marine reserves?

Unlike small marine protected areas, large no-take marine reserves provide safe havens for a wide range of migratory species, many of which are critical for the nutrition of coastal peoples. Because ecosystems in large no-take ocean reserves are generally healthier, they are also more resistant to pollution, climate change and other threats that adversely affect the well-being of the world's oceans and ultimately endanger the livelihoods, food security and economic development of millions of people. Very large reserves can help reduce these risks.

Ecologist Aldo Leopold once said, "To keep every cog and wheel is the first precaution of intelligent tinkering." Establishing large marine reserves is essential to saving all the parts. Large no-take reserves can provide critically important scientific reference sites for researchers to study how healthy ecosystems function. Only with that information will they know what steps to recommend to restore degraded ecosystems to health.

How do large no-take marine reserves fit with international targets for ocean conservation?

Large no-take marine reserves must play a significant role in reaching the goal of greater ocean protection. The median size of marine protected areas worldwide is 1.6 square kilometers. It would require 20 million such areas to protect 10 percent of our oceans. Clearly, there is a need to establish some very large no-take marine reserves to complement the smaller reserves, much as we have done on land in designating both very large national parks and small community parks. Given the state of our oceans and the plodding pace at which marine protected areas are being created worldwide, we need to seize every opportunity to designate large, highly protected marine reserves.

How does the work of Pew's Global Ocean Legacy contribute to global ocean conservation efforts?

Global Ocean Legacy, a project of the Pew Environment Group and its partners, works to protect and preserve some of the Earth's most important and unspoiled marine ecosystems through the establishment of very large no-take marine reserves. We challenge the conventional view that our oceans contain limitless resources that do not require the same type of protections enacted for our lands. In 2010, our efforts led to the establishment of the world's largest no-take marine reserve, the Chagos Marine Reserve in the Indian Ocean. 

Read coverage of the International Marine Conservation Congress and marine protection in Scientific American.

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Learn about past successes of Global Ocean Legacy on

Learn more about the International Marine Conservation Congress. 

Media Contact: Veronica OConnor

Topics: Oceans, Environment

Project: Global Ocean Legacy