1. Lecture 8: Aquaculture

2. Aquaculture Basics
Aquaculture = “refers to the breeding, rearing, and harvesting of animals and plants in all types of water environments including ponds, rivers, lakes, and the ocean” (NMFS)
Producing seafood for human consumption
Enhancing wild fish, shellfish, and plant stocks for harvest
Restoring threatened and endangered aquatic species
Rebuilding ecologically-important shellfish habitat
Producing nutritional and industrial compounds
Providing fish for aquariums
Fastest growing food sector in the past 40 years

3. Why Aquaculture?
Increasing global population + increased per capita seafood consumption = constant, growing demand for seafood 
“With capture fisheries production stagnating, major increases in fish food production are forecast to come from aquaculture. Taking into account the population forecast, an additional 27 million tons of production will be needed to maintain the present level of per capita consumption in 2030.” (UNFAO)

4.
NMFS

5. Why Aquaculture? Is a resource efficient means of food production
Protein
Feed Conversion Ratio
Salmon
1.2
It takes 1.2 pounds of feed to produce 1 pound of salmon
Beef
8.7
It takes 8.7 pounds of feed to produce 1 pound of beef
Pork
5.9
It takes 5.9 pounds of feed to produce 1 pound of pork
Chicken
1.9
It takes 1.9 pounds of feed to produce 1 pound of chicken

7. Global Aquaculture Production

9. Aquaculture in the U.S.
U.S. aquaculture industry (both freshwater and marine) meets only 5% to 7% of U.S. demand for seafood
75% of that is freshwater farmed catfish, trout, and tilapia
Marine aquaculture is only approx. 20% of U.S. aquaculture production and supplies approx. 1.5% percent of the entire U.S. seafood supply
Two-thirds of marine aquaculture is molluscan shellfish such as oysters, clams, and mussels.
The remainder is shrimp and salmon, with lesser amounts of barramundi, seabass, seabream, and other species
Source: NMFS

11. Risks/Problems Associated with Aquaculture
Destruction of habitat
Pollution/Eutrophication of nearby waters
Increased fishing pressure on wild stocks
Introduction of non-native species and genetically-modified species
Disease and parasites
Conflicts with local predators

12. Risk: Destruction of Habitat
Destruction of mangrove forests and wetlands for shrimp and fish farming
© Bertrand Coûteaux
Dierberg & Kiattisimkul 1996

13. Risk: Pollution and Eutrophication
Including nutrients, pharmaceuticals (antibiotics), pesticides, and herbicides
Increasing nitrogen inputs from fish farming shown by sea area (

15. Risk: Increased Fishing Pressure on Wild Stocks
Approx. one-third of the world’s fish catch is used to produce fishmeal and fish oil (both are used to make feed for farmed fish)
In 2004, the aquaculture industry used 87% of the world’s fish oil and 53% of the world’s fishmeal
Fish stocks used as feed - mostly anchovies, pilchards, mackerel, herring, and whiting
1 kg farmed tuna → up to 22kg of wild-caught fish  
1 kg farmed salmon → 4kg of wild-caught fish  
1 kg farmed marine shrimp →up to 2kg of wild-caught fish
Source: WWF

16. Risk: Non-Native and Genetically Modified Species
Many farmed fish escape from their enclosures
Basically become invasive species and can have the same types of effects on local ecosystems
Can dilute natural gene pool
Escapes of farmed fish in Scotland (

17. Risk: Disease and Parasites
Two main parasites in fish aquaculture industry:
Sea lice – ectoparasites
Saprolegnia (water molds)
Increased susceptibility to disease due to crowded conditions, stress, limited water flow
Disease pathogens may be native or non-native
Seachoice.org
Americanaquariumproducts.com

18. Risk: Conflicts with Predators
High concentrations of prey animals and waste food associated with aquaculture operations attract wild organisms ranging from seals, seabirds, and sharks to molluscs and crustaceans.
Predators can damage enclosures and feed on cultured organisms growing on the substrate
These predators are often killed (sometimes illegally)