210 likes | 475 Views
Aquaculture. Raising aquatic organisms in controlled environments for food Fastest-growing form of food production 6.9 million tons in 1984 33.3 million tons in 1999 One-third of world’s fish for human consumption >220 Species are farmed Shellfish Shrimp, Oysters, Mussels Finfish
E N D
Aquaculture • Raising aquatic organisms in controlled environments for food • Fastest-growing form of food production • 6.9 million tons in 1984 • 33.3 million tons in 1999 • One-third of world’s fish for human consumption • >220 Species are farmed • Shellfish • Shrimp, Oysters, Mussels • Finfish • Carp, Tilapia, Salmon
Forms of Aquaculture • Inland Ponds • Substantial habitat “alteration” • Easy to manage waste • Coastal Net Cages • Less habitat alteration • Difficult to manage waste
Inland Ponds Ecuadorian Shrimp Farms • Pro: • -Easy to manage • Con: • -Substantial habitat “alteration”
Net Cages British Columbia Salmon Farm • Pro: • -Less habitat “alteration” • Con: • -Difficult to manage
History of B.C. Salmon Farming • 1970’s: Small operations bought by multinational corporations • 1980’s: Fishermen, Tribes and Environmentalists oppose salmon farming • 1995: B.C. imposes moratorium • 2004: Farmed salmon found to have higher PCB than wild salmon
Why farm salmon? Columbia River Chinook (millions of kg)(from Beiningen, KT. 1976. Oregon D.F. W.)
Thirty-six PNW salmon runs listed under E.S.A. Causes: • Destruction of spawning habitat • Logging • Dams • No access to spawning habitat • Overfishing • Reduces returning salmon
Salmon Farming Problems • Contamination • Increases disease • Produces lots of waste • Ecologically inefficient • 5 kg wild fish =1 kg farmed salmon • Escaped farmed fish affect wild stocks • Spread disease • Reduce viability • Farmed fish are more polluted than wild (Science Jan. 2004) • Biomagnification of pollutants
Science January 9, 2004 “differences between the farmed and wild salmon contaminant concentrations are most likely a function of their diet.” (Hites et al., 2004)
Is aquaculture bad? No…if done ecologically • Scale is important • Small Scale = More Environmental • Herbivores better than carnivores • Herbivores are more efficient • Filter feeders actually clean the water • Integrates with other agriculture • Chinese Integrated aquaculture
Benefits of Aquaculture • Improves food security • Reliable protein source • 30% of world is malnourished • Can be very energy efficient • 10x more fish per unit area than ocean • Reduces pressure on wild fish • 70% of edible ocean fish are declining • Reduces by-catch
What you can do • Support with your $$$$ • Buy • Well managed, wild-caught salmon • Copper River Salmon is good • Farmed herbivorous Fish • Farmed filter feeders • Don’t Buy • Farmed salmon • Farmed shrimp • Resources • www.mbayaq.org/cr/seafoodwatch.asp