Oysters have been a New York City culinary staple for centuries. Hundreds of years ago, when the Indigenous Lenape people lived in the region prior to European colonization, the harbor teemed with shellfish. But by the early 20th century, pollution, urban development and overharvesting erased nearly 350 square miles of oyster beds.

Fast forward to the present, and a nonprofit is now working to revive the once-mighty bivalve. The Billion Oyster Project started seeding the harbor with oysters in 2010 to improve water quality, increase marine biodiversity and boost shoreline protection. Its efforts have been successful: The group is on track to meet its one-billion oyster goal by 2035.

In October, Timmy Broderick spent an afternoon measuring oysters with other New Yorkers to learn more about the project and the harbor’s marine life.