It’s frightening enough that 87% of the world’s assessed fisheries are fully or over-exploited. But it is even scarier to consider how little we know about the condition of most of the world’s fisheries, because four-fifths of them have never been scientifically assessed. A recent study in the journal Science is providing fresh insights into thousands of fisheries where data has not been previously available. These “data poor” fisheries make up 80% of the world’s catch and many are on the brink of collapse.

Despite the dire news, there is a bright spot in the study. The authors conclude that the ocean is nowhere near a lost cause and with the right management tools, the abundance of fish could increase by 56%. In some places, the study says, fisheries yields could more than double.

This isn’t just a big deal for the fish. As the authors of the Science study write, “When sustainably managed, marine fisheries provide food and livelihoods for hundreds of millions of people worldwide.” So what’s the key to seeing such a rebound become reality? An approach to overseeing fisheries known as rights-based management, or catch shares.

Over the past decade, catch shares have taken hold in U.S. waters, ensuring the sustainability of about 65% of the fish landed in the United States. This is the greatest unknown policy success of our time. Don’t take my word for it I work for the Environmental Defense Fund, a policy shop that has long championed the approach. Instead, consider the facts that helped lead the authors of the Science article draw that same optimistic conclusion.

Catch shares are a market-based management tool used in commercial fishing that, coupled with catch limits, have been successful in rebuilding fish populations while improving the efficiency and business of fishing. After decades of failed regulatory regimes, catch shares are working for fish and for fishermen. What’s unfolding before our eyes is a global behavioral economics study one that’s delivering major benefits to people around the world.

The Gulf of Mexico red snapper fishery, for example, was on the brink of collapse in the early part of the last decade. Fishermen were limited to 52-day seasons that were getting shorter every year. The shortened seasons, an attempt to counter overfishing, hurt fishermen economically and created unsafe “derbies” that often forced them to race into storms like the boats in The Deadliest Catch.

This short window also meant that all of the red snapper were being caught and brought to market at the same time, creating a glut that crashed prices. Many fishermen couldn’t even cover the cost of their trip to sea after selling their fish.

A decade ago, the Environmental Defense Fund began working with a group of commercial red snapper fishermen on a new and better way of doing business. Together, we set out to propose a catch share management system for snapper.

Simply put, fishermen would be allocated shares based on their catch history (the average amount of fish in pounds they landed each year) of the scientifically determined amount of fish allowed for catch each year (the catch limit). Fishermen could then fish within their shares, or quota, all year long, giving them the flexibility they needed to run their businesses.

This meant no more fishing in dangerously bad weather and no more market gluts. For the consumer, it meant fresh red snapper all year long.

After five years of catch share management, the Gulf of Mexico red snapper fishery is growing because fishermen are staying within the scientific limits. Boats that once suffered from ever-shortening seasons have seen a 60% increase in the amount of fish they are allowed to catch. Having a percentage share of the fishery means fishermen have a built-in incentive to husband the resource, so it will continue to grow.

Another major problem facing commercial fishing is known as discards a euphemism for the tragic waste of tons of fish thrown overboard dead. Under the Gulf red snapper catch share system, discards have decreased by half. Fewer wasted fish, along with a fishery that stays within its limits, are two keys to rebuilding the resource.

On the business end, fishermen have seen a 25% increase in the price they get for their landings of red snapper.

The economic incentives for sustainability are clear. Creating a responsible commercial fishery does not have to be at odds with the economic goals of fishermen. In fact, it can make those goals easier to reach.

The success of red snapper fishermen led to the creation of catch share programs for other species and in other regions grouper and tilefish in the Gulf of Mexico, groundfish in the waters off Northern California, Oregon and Washington State resulting in similarly impressive increases in revenue and decreases in waste.

In New England, a form of a catch share also produced promising results for groundfish. From 2009 to 2011, groundfish landings were up six percent, revenues for fishermen were up 18% and discards were reduced by two-thirds. But all is not well there. Warming Atlantic waters are leading to migration changes and increases in predator species that prey on cod and compete for food. Declining cod populations led the Obama administration to issue a Disaster Declaration to provide needed relief to fishermen. In New England, catch shares have kept a difficult situation from becoming even worse.

Now the idea is catching on elsewhere. The European Commission has proposed adoption of “Transferable Fishing Concessions,” a European version of catch shares that would increase fishermen’s incentives to comply with science-based catch limits. And earlier this year, the World Bank announced a global partnership for oceans that includes more than 100 other organizations governments, private sector interests and NGOs, including the Environmental Defense Fund to address issues related to overfishing, pollution, and habitat in the world’s oceans. Rights-based management programs like catch shares will be a major part of that strategy to address overfishing. At the same time, they will contribute to the health of the global economy; the World Bank estimates that failed fisheries management contributes economic losses of $50 billion annually.

As an experiment in behavioral economics, the results are striking. A look at the varying fisheries management approaches around the world shows that the industry behaves in very different ways under different sets of rules. Overfishing is not a given. The key to solving it is to take human behavior into account, giving the industry more rather than fewer rights and responsibilities, and developing financial rewards for stewardship of the resource. Catch shares accomplish all of this.

It’s all too easy to lose hope that human beings will ever rise to the challenge of solving the global environmental crises we face. But we should not despair. The catch shares success story demonstrates that people will respond when we get the right market signals in place.

In other words, we don’t have to change human nature to save the seas. We just have to change human incentives. And catch shares give us a very effective way to do just that.

2013 Harvard Business School Publishing