Water Resources Research Act Program

Details for Project ID 2015NJ371B

Effects of hard clam (Mercenaria mercenaria) grow-out operations on benthic communities in Barnegat Bay, NJ

Institute: New Jersey
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-28
Total Federal Funds: $5,000 Total Non-Federal Funds: $11,162

Principal Investigators: Rebecca Shell, Robert Prezant

Project Summary: Hard-clam (Mercenaria mercenaria) aquaculture operations maintain densities many magnitudes higher than those found naturally. Though there is ample research describing the negative effects seen from the physical harvesting of the clams, little work has investigated the effects of the 2-3 year grow-out phase on the ecology and biodiversity of the associated benthic communities. Literature-based predictions are split as to whether or not inflated hard-clam densities will affect overall invertebrate biomass and/or biodiversity, either positively or negatively. Though the high densities maintained during grow-out might be expected to detrimentally impact local communities due to locally-increased nutrient input and subsequent oxygen depletion, we hypothesize that the filtering capability of this bivalve will provide a net benefit to local communities in Barnegat Bay, an impacted, eutrophic, lagoonal estuary, due to an increase in total filtering capacity. Plots of three treatment types (industry-standard screens with clams, screens without clams, and control) were installed at Sedge Island, Barnegat Bay, in 2012. Samples are taken in May, August and October of each year for three years. Preliminary data (2012-2013) indicates an increase in non-target molluscan biomass but a slight decrease in overall taxa richness in the screened experimental plots. Final results indicating such an enhancement of non-target molluscan biomass and overall associated benthic biodiversity could potentially lead to an increase in permitted hard clam lease acreage in New Jersey as part of an improved management strategy.