New York seeks to claw back 'Big Oyster' past

One sunny morning in New York, a dozen biologists and volunteers stand in knee-deep water, chucking net sacks of oyster shells down a human chain, before planting them in containers on the riverbed.

Why? To build an oyster reef.

The goal? To restore a billion oysters by 2035 to America's largest city -- not as a delicacy for the dinner table but in an environmental bid to clean up its notoriously filthy harbor water and generate greater biodiversity.

Dressed in waders, the group battles under the hot morning sun on the Brooklyn shoreline, the Statue of Liberty and iconic skyscrapers of New York's Financial District rising up on the horizon.

The net sacks contain empty oyster shells, or ones that have been assiduously cleaned or "cured" -- then inserted with oyster larvae -- and placed into containers planted on the seabed that will form a reef.

"This was the Big Oyster before it was the Big Apple," jokes Mike McCann, an urban marine ecologist with the non-profit group The Nature Conservancy.

"That's a history that has been forgotten by a lot of New Yorkers and this project brings it back," explains the 32-year-old.

When English explorer Henry Hudson sailed into New York harbor in 1609, he had to navigate 89,000 hectares of oyster reefs that fed Lenape Indians for generations, writes Mark Kurlansky in his 2006 book "The Big Oyster".

The Dutch colonialists who followed knew today's Ellis Island and Liberty Island as the Island of the Little Oyster and the Island of the Great Oyster.

"Oysters are ecosystem engineers and they build (a) three-dimensional reef habitat," explains Katie Mosher, restoration manager of the Billion Oyster Project (BOP), which was set up in 2014.

"It's full of different shapes and sizes of oysters that other species love to hunt in and live in and to search for prey," she adds.

Oysters also filter and clean the water when they breathe, making it clearer. This enables light to penetrate more easily to the bottom and allows more plants to grow on the seabed.

The molluscs also recycle nutrients and nitrogen, and can even mitigate the energy of large waves, reducing flooding and preventing erosion during storms or hurricanes.

But New York's original oyster population was almost extinct by the dawn of the 20th century, a victim of overfishing, industrial age pollution and sewage.

The waters of New York became too toxic to cultivate much marine life until the Clean Water Act of 1972 prohibited the dumping of untreated wastewater and garbage. Since then, life has slowly returned.

"I had no idea there were oysters in New York City!" exclaims Emma Latham, 22, one of the volunteers and recent ecology graduate from Princeton University.

"I think it's just great that we are able to take any small piece of land and make it do more, because there's such a dire environmental impact by having so many people in such a small space with so much concrete."
"We definitely noticed an improvement when we put oysters down on the bottom," said Mosher. "There's more fish, more crabs. And it happens right away."