Shellfish Restoration

Are you looking for information on how to shellfish on your own or with the NSRWA?

Blue Mussel Beds as of 9-23-16

Last Friday our watershed ecologist, Sara Grady, went for a snorkel in the North River to check on the blue mussel beds that we tried to establish by placing 649 mussels from docks into the North River (and 767 into the South River.) Sara found not only our mussel beds with the mussels still alive, but also green crabs burrowing into the mudflat, European oysters, and quite a few sea stars. She also discovered that the base of the 3A bridge and the pilings from the old 3A bridge are also covered with mussels. If you’ve ever wondered what the bottom of the North River looks like, here are the photos (Click photos to enlarge) and here is the video.

blue-mussels-sea-stars-green-crabs-2

Blue Mussel Enhancement Project History

The goal of this project is to a) explore the feasibility of raising mussels in culture in the North River, including growth and survival of mussels of different sizes b) supplement the natural spat supply of the North River by increasing the abundance of adult mussels present in the system.

The North River includes 299 acres of conditionally approved shellfish growing area (MB5.1), with an additional 313 acres of conditionally approved shellfish growing area in the adjacent South River (MB6.1). Both rivers have existing populations of blue mussels (Mytilus edulis), although the extent of the North and South Rivers mussel beds have decreased substantially since the 1980’s. This decline has been primarily attributed to a limited commercial harvest, although in recent years other causes like invasive crab predation have possibly played a role in reducing the abundance of mussels in the rivers.

In late July 2013, NSRWA interns conducted preliminary field surveys along both rivers. Flat outcrops of river bank were surveyed at low tide by walking along the selected area. In multiple locations of historic mussel beds, small patches of existing successful blue mussels in subtidal areas were observed.  Additionally, three mooring chains and a floating dock that had been installed in the river for longer than a year were examined. All of the floating structures had dense blue mussel growth.

During 2014 we took a double-pronged approach to restoring mussels in the rivers. First, we collected ~300 25mm (~1 inch) mussels off a dock and placed them in a culture sock to grow while suspended in the North River. We also deployed spat collectors and grew up the spat we collected in mesh bags for eventual placement on subtidal rocks. Unfortunately these mussels were lost, but we were able to collect another 300 mussels from docks and placed those in intertidal and subtidal areas in the North River. We are watching to see how well these mussels grow and survive through 2015.

 Shellfish Bed Openings

In conjunction with our water quality monitoring and the impressive stormwater management work that many of our communities have accomplished, we are always looking to increase the total acreage of approved or conditionally approved shellfish beds in our watershed and beyond, as well as increase the amount of time that these beds remain open each year. We tackle this by implementing water quality improvement projects but also working with MassDMF to assess the status of these shellfish beds on a regular basis.