New Calculator Helps Oyster Growers Measure the Water Quality Benefits of Farms

The new tool provides a science-based estimate of how much nitrogen oyster farms remove from local waterways. It generates a report that can be used in the aquaculture permitting process.

When it comes to removing excess nutrients from waterways, shellfish are a powerhouse. The NOAA Milford Lab in Connecticut studies the environmental benefits—also called ecosystem services—that shellfish provide. Nutrient removal is a particularly valuable ecosystem service.

Nutrients like nitrogen are essential to life, but often excess nutrients end up in coastal waters from human sources including lawn fertilizer and agricultural runoff. When this goes unchecked, algae can grow out of control. This can cause environmental problems including low dissolved oxygen, fish kills, and dead zones. Oysters and other bivalves—shellfish with two shells— help keep nutrients in check by filter feeding on algae. While they feed, these mighty shellfish improve water quality. This effect has been well documented by scientists, although it is not typically considered within the aquaculture permit review process.

Scientists from the Northeast Fisheries Science Center and the National Centers for Coastal Ocean Science created an online tool for oyster growers in the Northeast United States. They can use it to get a science-based estimate of how much nitrogen their farms remove from local waterways. The publicly available Aquaculture Nutrient Removal Calculator also generates a report that growers can include in their aquaculture permit applications. The team published the science behind this new tool in the journal PLOS ONE (open access). They are actively seeking feedback from the shellfish aquaculture community to help improve the tool. Send feedback to: [email protected].

“We’ve heard from both regulators and industry members that they need a simple, intuitive way to calculate the environmental benefits shellfish aquaculture provides,” said project lead Julie Rose.