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Salmon. Elaine Christian. Taxonomy. * Atlantic Salmon ( Salmo salar ) * Salmon Trout ( Salmo gairdneri --> Oncorhynchus mykiss ) Anadromous : Steelhead salmon/Ocean trout Non- anadromous : Rainbow trout Coho Salmon ( Oncorhynchus kisutch ) Chinook Salmon ( Oncorhynchus tshawytscha ).
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Salmon Elaine Christian
Taxonomy • *Atlantic Salmon (Salmosalar)* • Salmon Trout (Salmogairdneri--> Oncorhynchusmykiss) • Anadromous: Steelhead salmon/Ocean trout • Non-anadromous: Rainbow trout • Coho Salmon (Oncorhynchuskisutch) • Chinook Salmon (Oncorhynchustshawytscha)
Facts • Angling, food, commercial values • Market price: $5-7/kg • Market locations: everywhere • Norway, Chile, United States: Maine & Washington
Life Cycle Salmon Life Cycle Song
Reproduction in Captivity • Anaesthetized • Eggs/sperm stripped • Mix, wash, place into freshwater tanks • Adults placed in clean, aerated water to recover
General Production Methods • Hatched from eggs, raised in freshwater tanks • 12-18 months (smolt: juvenile) put in floating sea cages/net pens anchored in bays along the coast • Kept in pens for another 1-2 years • Harvested
Production Methods • Modern Commercial Hatcheries • Shift from net pens to RAS – water recycled within the hatchery • Doesn’t have to rely on freshwater source • Conventional Hatcheries • Spring water flows through hatchery • Eggs hatched in trays, smolts produced in raceways • Waste discharged into local river • Use more than 100 tons of water to produce 1kg of smolts
Sea Cages/Net Pens • Large cage can hold 90,000 fish • Seafarm: cages placed side by side with floating walkways alongside • Other nets around the cages to keep out predators • Stocking density for Atlantic Salmon: 8-18kg per cubic meter
Feeds & Feeding • Carnivorous fish • Currently: fish meal with wheat byproducts, soybean meal, feather meal • Various carotenoids to make their flesh match the color of wild salmon • Need proteins, 5-20% fat, 9-12% carbohydrates • 2-4kg wild caught fish = 1kg of salmon
Conditions • Good water quality • High water exchange rates • Currents fast enough to prevent pollution of the bottom but not fast enough to cause pen damage • Heavy metals collect (copper, zinc) • Dim light • Reasonable water depth • Distance from infrastructure (ports, airports)
Advantages/Disadvantages • Money ($1.6 billion industry - Chile) • Farmed fish = large numbers = less $$ • Health benefits • Omega-3 • Diseases/parasites • Toxins found in flesh (heavy metals accumulate) • Escapes – compete with native wild species for food & habitat • Reduce genetic diversity • Consume more fish than they produce as a final product