The Charles River used to be teeming with oysters. Up until the 20th century, oysters could be harvested in the Charles that were up to a foot long! These amazing bivalves are filter feeders and can process and filter up to 30 gallons of water a day and undergo nitrogen fixation.
However, due to loss of habitat through river fill, pollution, and over harvesting, oysters have not been present in the river for decades. Thanks to a group called the Massachusetts Oyster Project, oysters were reintroduced in the Boston Harbor in 2008! They placed 150,000 oysters at the mouth of the Charles River. Due to the dam placed at the Museum of Science in the early 1900’s, the Charles River is no longer an ideal habitat for oysters. The brackish water- or mix of salt and freshwater at the mouth of the Charles is the perfect spot for oysters. The spot is also ideal because it's an area where it's difficult for people to harvest them. This is especially important for oysters that also filter and process sewage- they could be carriers of salmonella or other harmful bacteria.
Each year the Massachusetts Oyster Project places more oysters that have been lost due to predation or mortality from too much silt. To see more about this cool project, or perhaps to volunteer to help seed the Boston Harbor with oysters, please visit www.massoyster.org