Managing Aquaculture to Protect Water Quality

How NPDES Permits for Aquaculture Facilities Protect Water Quality

• Pollutants of Concern for Aquaculture
• NPDES Permits for Aquaculture
• Aquaculture Water Quality Management

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Pollutants of Concern for Aquaculture

Pollutants of concern often associated with aquaculture include:

• Total suspended solids, settleable solids
• Biological wastes (metabolic waste, unconsumed feed)
• Floating and submerged matter 
• Five-day biochemical oxygen demand, low dissolved oxygen
• Nutrients (phosphorus and nitrogen), ammonia
• Drugs that are unconsumed or unmetabolized
• Chemicals, such as anti-fouling agents

NPDES Permits for Aquaculture

NPDES permits establish regulatory frameworks to set pollution controls and demonstrate that those controls are working. This 10-minute video describes how NPDES permits applies to discharges from aquaculture operations.

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Aquaculture Water Quality Management

NPDES permits for aquaculture facilities include effluent limitations that control the discharge of pollutants. Effluent limitations may be numeric or narrative. Numeric limits specify the maximum amount of a pollutant that may be discharges over a certain period, usually a day or a month. Narrative limits include Best Management Practices (BMPs) or requirements to minimize or eliminate discharges.

NPDES permits for concentrated aquatic animal production (CAAP) facilities that produce 100,000 pounds or more of aquatic animals must  include requirements to implement the effluent guidelines established at 40 CFR Part 451. These facilities are subject to reporting requirements regarding:

• The use of certain drugs;
• Unanticipated discharges; and
• Developing and maintaining a BMP plan.

CAAP facilities using flow-through and recirculating systems and net pens are subject to additional requirements dictated by the effluent guidelines. NPDES permits for these facilities include requirements for:

• Solids control (flow-through and recirculating systems only);
• Feed management, waste collection and disposal, transport or harvest discharge, and carcass removal (net pens only);
• Materials storage;
• Maintenance;
• Recordkeeping; and
• Training.

NPDES permits for non-CAAP aquaculture facilities may contain similar requirements. Sometimes, NPDES permits for both CAAP and non-CAAP aquaculture facilities may require other water quality management activities, such as monitoring for drug and chemical application, or escape prevention and response plans.

Explore the interactive graphics below to learn more about common types of BMPs that may be included in NPDES permits for flow-through and net pen aquaculture facilities.

Select each activity for a description of how it protects water quality. The activities shown are examples only and may not be required or appropriate at every aquaculture facility. Refer to the applicable NPDES permit to determine which activities are required for a specific facility.

View a text version of the graphic, Best Management Practices for Flow-Through Aquaculture.

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View a text version of the graphic, Best Management Practices for Net Pen Aquaculture.