1. Environmental Impacts of Aquaculture Effluents
Josh Vinson

2. Aquaculture Industry Increase in seafood demand due to:
1. Increased per capita consumption
2. Increased global population
Wild food fish populations currently being over fished
Wild caught fish production has remained steady at mT /yr since early 1980’s
Wild caught fish production can’t be increased
Increased seafood demand must be met with increase in cultured seafood
-rapid industry growth = environmental concern?

3. Aquaculture Effluent
Effluents: refers to either a continuous or intermittent discharge of a liquid from an aquaculture facility
Effluent composition
Dissolved compounds
1. Phosphorus
2. Nitrogen
Sludge
Fecal material and uneaten feed

4. Dissolved Compounds Phosphorus and Nitrogen Organic matter
Cause eutrophication
Algal blooms
Kills fish and other benthic organism
alterations in food chains
removal of oxygen
Organic matter
Increased BOD
Decreases DO in water column and sediments
Alters benthic food chains and ecology
Can kill higher life

5. Sludge
Sludge: refers to the solid particulate portion of aquaculture effluents.
Composed primarily of fecal material and uneaten feed.
Volume directly related to feeding rates.
Nutrients (P, N), and organic matter leaches out or is broken down and ultimately becomes dissolved compounds.
Impacts are the same as those for dissolved compounds, but management and treatment differs.
End product of sludge treatment is typically used as agricultural fertilizer.

6. Aquaculture Methods And Associated Degree of Environmental Impact
3 Broad categories of aquaculture
Extensive
Deals primarily with shellfish
slow, low-volume, dilute continuous waste
Semi-intensive
Cages
High stocking densities
large volume of continuous, untreated waste released
Raceways
large volume of continuous, treated waste.
Ponds
Intermittent release of, treated waste.
Intensive
Closed – recirculating systems (CRSs)

7. Aquaculture Methods

8. Management Strategies
Goal: Reduce environmental impact of aquaculture without decreasing production
Funding for research
Improve feed conversion ratios (FCR) –ratio of gain in wet body weight to the amount of feed fed
Improve organism-specific feeds to increase nutrient retention.
Improve waste treatment methods
Educate Farmers on:
Method benefits and drawbacks
Integrated aquaculture techniques
Ex Waste-water-fed mollusk farming can be used to recover excess nutrients
Best Management Practices (BMP) plans
Encourage communication between researchers and commercial facilities via conferences and meetings