Oyster Upwellers
One of our most active program areas is our upwellers. We currently support four upwellers across Massachusetts. Upwellers provided a protected environment for oysters to grow to a size until they can survive on their own. In the beginning of the summer, we buy baby oysters, called spat, from a supplier. They begin as the size of red pepper flakes, and will grow to about an inch by fall. At that point, we release the oysters at locations we have arranged. Each upweller shows how oysters improve water quality, helps grow oysters for our restoration efforts, and serves as important tools to get the general public interested in shellfish conservation.
Mature oysters grown in our upweller. In the past three years, we’ve released over 400,000 native oysters.
Our upwellers
We have upwellers in:
How Upwellers Work
An upweller is a system used to grow shellfish. Think of it as an incubator for oysters. Oyster seed, called spat, starts the size of a grain of sand. The upweller is a system of individual cylinders through which ocean water is pumped. That circulates plankton from the ocean, which provides food for the baby oysters. They grow in the protected environment until they are large enough to release in the wild.
Planting Oysters
Planting oysters in a tidal estuary in Ipswich.
We are very careful about where oysters go after they leave our upwellers. Current state regulations prohibit the release of oysters in restricted waters. Prior to release, we work with the Division of Marine Fisheries and the town's shellfish warden or constable to select appropriate release sites.
In the summer of 2018, we conducted a habitat suitability study on the North Shore, and we identified locations well suited for oyster propagation. Oysters do best on hard substrates, such as rocks or pebbles, as opposed to sandy or muddy habitats. For this reason, oysters don't compete with clams for habitat. This is important on the North Shore, where the clam harvest is an important industry.