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What’s an Acre of Seagrass Worth?


Philine zu Ermgassen, Dr. Mark Spalding

Postdoctoral Fellow, Cambridge University; Senior Scientist, The Nature Conservancy

March 2014

Starfish in seagrass, Jardines de la Reina, Cuba. Photo credit: © Ian Shive
Starfish in seagrass, Jardines de la Reina, Cuba. Photo credit: © Ian Shive

For decades, dire tales of collapsing fish stocks were told, only to fall on deaf ears.

Then, in a 2008 report, “Sunken Billions,” the World Bank and the FAO began to couch the problem in entirely new terms—financial terms. They estimated that $50 billion was lost each year due to poor fisheries management. That staggering figure caught the eye of finance ministers, development agencies and economists around the globe.

At last, the conservation community discovered how to get attention, but it raised a new question: what to do about it? To truly turn the tide, they knew it meant not only taking fewer fish, but also producing more. That’s where seagrass, mangroves and other habitat come in. These habitats are nurseries to new generations of commercially valuable fish and it is time we recognize the value of those important ocean services on Earth’s balance sheet.

Juvenile fish have it hard from day one. They are at the mercy of the elements and voracious predators. The odds of a microscopic fish larva making it to adulthood are one-in-a-million. Seagrasses represent the rare safe haven, providing much needed food and shelter. And yet, like the fish, seagrass beds have also been disappearing. Some say the world loses a soccer field worth of seagrass every half-hour, further contributing to the decline in fish.

New fisheries management has to consider the whole life cycle of the fish—where they are born, where they spend their lives, as well as how they die.

In places where habitat loss harms fish, protection and restoration are a very real opportunity. A new study, supported by The Nature Conservancy, tells us just how real. The report tells us that each square meter of seagrass habitat we save in southern Australia could add nearly one kilogram of fish each year. Said in a different way, every acre of seagrass could add USD$8,000 of commercially important fish to the oceans every year.

No one is blind to the fact that seagrass restoration is both technically challenging and financially expensive, but these figures show that the benefits far outweigh the costs. Some restoration efforts could pay for themselves in just five years. In these terms, seagrass restoration is a no brainer.

A volunteer examines a clam during a massive seagrass restoration effort at The Nature Conservancy’s Virginia Coast Reserve. Photo © Mark Godfrey/TNC
A volunteer examines a clam during a massive seagrass restoration effort at The Nature Conservancy’s Virginia Coast Reserve. Photo © Mark Godfrey/TNC

And yet, as with so many projects where the costs are large and the benefits are shared, money can impede getting seeds in the ground. If such benefits went on the balance sheet of a company, a champion would certainly appear, but these benefits go to many—to commercial and recreational fishermen, to local economies and to seafood fans—and thus no champion is forthcoming.

On an encouraging note, however, the story of the financial impact of a small patch of seagrass in a small part of the world is but one among the many that our ocean has to tell. Valuing ocean wealth stands to change everything. It represents a fundamentally new model for the global conversation. It has been reviewed and tested by the scientific community.

We can use it to build a complete accounting of coastal wealth that includes jobs, food security and tourism income into an honest and compelling bottom line figure. Suddenly, that little patch of seagrass in South Australia is no longer “dead space” able to be snuffed out by a change in shipping lanes—run-off or pollution—but rather a storehouse of wealth.

Humans crave quantification. Numbers turn heads. Numbers change policies. Numbers are compelling. But we must act fast. Seagrasses are being lost every minute we wait. And, it’s costing us untold billions.

We can start by mapping our ocean wealth, like a pirate would plot his hidden treasure. We can start understanding things like how valuable mangroves are at filtering out pollution, or coral reefs in generating tourism, or oyster beds are at protecting coastal erosion. We must build these systems into our economic models in the realest, most compelling financial, engineering and policy terms we can find. Tabulating the value of services is essential if we are ever to truly comprehend the vast wealth of the ocean and maximize investment and development dollars.

Philine zu Ermgassen is a postdoctoral fellow at Cambridge University. Dr. Mark Spalding, is a senior scientist at The Nature Conservancy.

Originally Posted on National Geographic

March 31, 2014