Shellfish

Shellfish/Aquaculture:  The Town of Wellfleet is a recognized leader in the shellfish industry and has focused on shellfish restoration and aquaculture research over the past several decades.  Inherent in this approach is a belief that the marine ecosystem must be restored to enable it to metabolize and assimilate both natural and anthropogenic nutrient loads.  

A pilot project conducted by the town in conjunction with University of Massachusetts and the Center for Coastal Studies reported significant water quality improvement in the inner harbor area.  Recent updates to the Cape Cod Commission’s Technology Matrix (2017) indicate a range of potential nitrogen mitigation associated with shellfish and aquaculture ranging from 52 – 300 kg/acre-year for these projects (see Table below).  These analyses are based upon harvesting of shellfish and removal of the nitrogen-laden tissue.  They are also based upon assumed shellfish densities.

There is evidence that additional nitrogen attenuation (beyond removal rates associated with uptake and harvest) occur in the benthic zone associated with shellfish ecosystems.  This includes research in the Chesapeake Bay region and more recently on Cape Cod in the towns of Falmouth and Orleans.   A recent publication prepared by University of Massachusetts SMAST (2019) reports denitrification rates referred to as “oyster effect” of 24 – 36% (compared to the harvest removal rates) during the first two years of a study in Lonnies Pond in Orleans associated with the biodeposits.