For years, studies have been done to show the negative impacts of aquaculture on receiving streams. Environmental damages include destruction of wetlands, increased nutrients (nitrogen & phosphorous) in the effluent, and organic pollution from animal wastes.
A recent study of the Potamac River by researchers from the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS) used modeling and scientific evaluations to estimate that virtually all nitrogen pollution (leading cause of algae blooms in brackish water such as the Chesapeake Bay) can be eliminated if 40% of the river bed were used for shellfish cultivation. Even using just 15- 25% of the river bed can remove up to 50% of the nutrients.
The nutrients are removed by the filter feeding process of the oysters. The removal of organic particles and nutrients will result in lower nutrient loadings entering the imperiled areas of the Chesapeake Bay. This filtering would also increase dissolved oxygen residuals, reducing the dead zones often seen in polluted waters.
Intensive aquaculture relies on stocking ponds heavily and using both mechanical aeration and feed addition to produce large amounts of seafood. While increasing yields exponentially over natural ponds, this process has problems with off-flavors, diseases, and low feed conversion that can be traced back to buildup of pollutants and pathogenic microbes.
While I have long focused on treating wastewater, Aster Bio was asked to investigate if microbes could improve productivity in shrimp farms and reduce off-flavors in catfish farms. We looked at the wastes causing the pollution including ammonia/nitrite buildup. Additionally, we considered how beneficial microbes could enhance feed conversion and competitively exclude pathogenic microbes. After studying the problems and surveying ponds, we tested multiple formulations to see if adding microbes could changes pond ecology and enhance yields. The results are below:
Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.
Click to set custom HTML