THE BRONX - Baykeeper volunteers come to the Bronx River every two weeks every summer to monitor the oysters in the area.

Volunteers say they started doing research in the area to figure out how to start bringing oysters back to the harbor.

When they started 10 years ago, they noticed native oysters were few and far between. 

Data collectors say more oysters this year were able to reproduce because of better food and water quality.

Oysters also help filter waters and build reefs that help stop flooding during storms and provide shelter for other organisms.