Using Bivalves as an Indicator for Fecal Bacteria

This project focuses on the integration of fecal bacteria from warm-blooded animals into bivalve tissue, and the utilization of bivalves as an indicator for fecal bacteria in waterways. Bivalves may give a more representative long-term average of fecal bacteria in water as compared to direct water testing. The primary objective is to create a standard operating procedure to use bacterial testing of bivalves as a proxy for bacteria concentration in the water. This method can be used in places where bivalves do not already exist by adding them to a body of water, or by collecting bivalves that already exist in a water body, and in both cases, then testing them for fecal bacteria contents. We conducted a study measuring fecal coliform in Oxecossett Brook, Stonington, CT, over 8 consecutive days, then tested the coliform content of existing wild ribbed mussels (Geukensia demissa) at the collection site on the final day. The average fecal coliform from direct water testing was 1243 MPN/100mL and the average fecal coliform in mussel collected was 91 MPN/g. The results show that ribbed mussels may be a good indicator of bacteria levels, but more research is needed.