Lecture 8: Aquaculture

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

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)

www.thatorganicgirl.com www.seachoice.org www.cbf.org NMFS www.labor4sustainability.org

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

Global Aquaculture Production

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

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

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

Risk: Pollution and Eutrophication Including nutrients, pharmaceuticals (antibiotics), pesticides, and herbicides www.fao.org Increasing nitrogen inputs from fish farming 1990-2004 shown by sea area (www.scotland.gov.uk) www.wri.org

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

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 2002-2007 in Scotland (www.scotland.gov.uk)

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

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)