Design and analysis of a sustainable oyster aquaculture business for the West and Rhode Rivers

Abstract

The water quality in the West and Rhode Rivers (WRR), two mezohaline sub-estuaries of the Chesapeake Bay, has declined due to local runoff of excess nutrients and total suspended solids (TSS) entering from the Chesapeake Bay. Previous research identified the feasibility of using large colonies of bi-valves (e.g. oysters or clams) in the river to remove the excess nutrients. Based on this research, an experiment conducted by the Smithsonian Environmental Research Center failed to establish a colony of clams due to naturally arising variability in salinity levels. Unlike clams, oysters are resilient to variations in naturally occurring environmental conditions, however, due to a lack of frequent reproduction by the oysters they are unable to build and sustain a viable oyster colony with critical mass. The goal of this paper is to evaluate the feasibility of a self-sustaining oyster colony, by harvesting a portion of the colony to fund the purchase of additional oyster. Design alternatives were evaluated for growing the colony((i) Remote Setting aquaculture, (ii) Nursery aquaculture, and (iii) Spat-on-shell aquaculture), and for distribution of the oyster product (shucked, half-shell). Three models were used to evaluate these design alternatives; (1) an oyster growth model to simulate the growth rate and survivability of oysters using stochastic environmental variables, (2) a 2D Tidal Mixing Model (2DTMM) to simulate the dynamic flow of nutrients and sediment within the WRR, and (3) a financial model to simulate the sustainability of an oyster aquaculture business with deterministic prices and demand. An analysis of cost versus utility (sustainability, public approval) shows that a 10 million remote setting aquaculture system sold at half shell would be the most cost-effective and sustainable alternative.