Shellfish aquaculture can provide a variety of ecosystem services beyond food production. Shellfish aquaculture gear creates complex structure that can increase the abundance and diversity of wild fish relative to reference habitats such as mud and sand bottom. A variety of life stages of fish have been observed in association with aquaculture gear, and occurrence of habitat-related behaviors such as foraging, shelter, and reproduction have also been documented on gear. Shellfish can reduce excess nutrients in the nearshore environment by assimilating nutrients into their tissue and shell as they feed and grow and promoting excess nitrogen removal by augmenting denitrification rates in surrounding sediments. Provisioning of this nutrient reduction service has been formally recognized through incorporation of shellfish aquaculture into nutrient management programs in two estuaries in the Northeast United States.
Through a combination of synthesis of the existing literature, and collection of regionally-relevant data, our program seeks to provide shellfish resource managers with an assessment of nutrient and habitat provisioning by shellfish farms in the Northeast region. The assessment is focused on the three most commonly cultivated species in the region: Crassostrea virginica, Mercenaria mercenaria, and Mytilus edulis. Existing literature on nutrient content of all three species indicates low variability in space and time, suggesting that nutrient reduction services are consistently provided region-wide. Existing literature on habitat provisioning suggests that gear used to cultivate all three species can increase the abundance of wild fish relative to reference habitats. Ongoing research programs in New Jersey, Connecticut, and Massachusetts seek to understand how habitat services provided by oyster aquaculture may vary according to factors such as location, season, cultivation practices, and gear types. Results from the synthesis and the regional research programs will be discussed, and data gaps identified. Information on region-scale variation in ecosystem service provisioning associated with shellfish aquaculture can aid resource managers in developing a permitting framework that includes consideration of environmental benefits in addition to potential impacts.