New York is rebuilding its polluted harbour one dead reef at a time, seeding 150 million oysters to filter the water: One site alone went from 20,000 oysters to 122 million

For more than a century, New York Harbor lost the species that once defined it. Pollution, dredging, shoreline development and relentless harvesting reduced the harbor’s vast oyster reefs to scattered remnants, stripping away an ecosystem that had filtered water, sheltered marine life and softened waves long before skyscrapers lined Manhattan.

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