Effects of Restoring Oysters on Water Quality

There is great interest in the potential for shellfish, which are filter-feeding organisms, to help clear the water by grazing down the microscopic plants in the water column, called phytoplankton. A number of communities have expressed interest in exploring restoration of shellfish, in particular oysters, specifically to improve water clarity.  This aspect of shellfish biology is also one of the benefits of aquaculture of these species.  As the cultured shellfish filter their food from the water and grow out to finally be harvested, the nutrients they gathered in from the phytoplankton are removed from the system.  This is of interest as there is concern over the increased input of nutrients (particularly of nitrates) to local estuaries and embayments degrading water quality conditions.

We are beginning projects with other researchers to test the effect of oysters and other shellfish on water clarity, denitrification rates and the ability to improve water quality.  We hope to have more information available soon...

For more information on water quality and nitrogen inputs in Massachusetts estuaries, check out the Massachusetts Estuaries Project.