Shellfish Culture is Good for the Environment
Those of us who grow shellfish have known all along that aquaculture is good for the environment, but we now have a growing body of research to back up that assertion. Shellfish clean the water, remove nitrogen, accelerate denitrification, enhance water clarity and promote eelgrass survival. In addition, oysters provide excellent habitat for myriad juvenile fish and crustaceans. All this and they taste great and are good for you too!
Listed below are links to some resources and write-ups of scientific research.
In a June 2018 study published in Frontiers in Ecology and the Environment, researchers compared various food–production systems in terms of their impact on the environment. They examined how farmed livestock, farmed fish and shellfish, and wild–capture fisheries performed against four metrics of environmental impact (energy use, greenhouse–gas emissions, release of excess nutrients such as fertilizer, and contribution to acid rain). Farmed shellfish had among the lowest environmental impacts across nearly every metric.
Sustainable Oyster Aquaculture, Water Quality Improvement and Ecosystem Service Potential in Maryland's Chesapeake Bay
This poster summarizes the work done by the University of Maryland's Matt Parker, and Suzanne Bricker of NOAA's National Centers for Coastal Ocean Science. It was presented at the Feb. 2018 World Aquaculture Society meeting in Las Vegas.
After sampling water and oyster growth at several farms in Maryland, the authors ran the data through the FARM model to estimate production and nutrients removed, and then assigned a dollar value for those removed nutrients.
Researchers at the NOAA Fisheries Milford Lab used GoPro cameras and water-collecting gear to study how oyster farm cages are providing beneficial habitat for wild species.
(Watch a video showing black sea bass congregating around one of the cages.)
This exhaustive scientific review, originally published in Aquaculture in 2009, examines how bivalve aquaculture — most notably oyster and clam culture on the West Coast — influences estuarine systems. Authors are Brett R. Dumbauld, Jennifer L. Ruesink and Steven S. Rumrill.
In this 2007 article published in the Transactions of the American Fisheries Society Jessica Tallman and Graham Forrester showed that oyster cages were similar to artificial reefs and natural cobble reefs in terms of habitat quality for scup and tautog.
Since oysters are 1.4 percent nitrogen by weight, harvesting 10,000 oysters for weekly deliveries to customers removes about 23 pounds of nitrogen and 2.3 pounds of phosphate from growing waters. This is equivalent to the annual nitrogen output of a single waterfront homeowner!
Odd Lindahl et al. presented an economic analysis of a mussel farm in Sweden that removed 39 Tons of nitrogen from a fjord annually at a substantial savings compared with a proposed land-based sewer treatment upgrade.
Comparing the Habitat Value of Shellfish Aquaculture Gear, Submerged Aquatic Vegetation and a Non-Vegetated Seabed
In 2004 University of Rhode Island graduate student Brian Kilpatrick compared the abundance and diversity of organisms congregating around eelgrass with those on oyster cages. His thesis research showed that the abundance of small fish, crustaceans, and invertebrates in the oyster cages was about ten times that in the eelgrass beds, and that the diversity indices at the two sites were about the same. He counted thousands of fish, crabs, and lobsters in the oyster cages, including hundreds of juvenile tautog, black sea bass, and other commercially important species. Kilpatrick's paper appeared in vol. 23 of the Journal of Shellfish Research.
This guest editorial appeared in the December 2003 issue of World Aquaculture. Written by Sandra Shumway, Chris Davis, Robin Downey, Rick Karney, John Kraeuter, Jay Parsons, Robert Rheault and Gary Wickfors.
In 2002, Roger Newell and colleagues at the University of Maryland suggested that bacteria in the sediment around oyster bars remove at least 20 percent of the nitrogen in oyster wastes through denitrification, the same process used in modern wastewater treatment plants.
You can read Newell's original paper that appeared in the September 2002 issue of Limnology and Oceanography, titled, "Influence of Simulated Bivalve Biodeposition and Microphytobenthos on Sedimentary Nitrogen Dynamics: a Laboratory Study."