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Aquaculture Systems
Types of systems
• Cage
• Raceway
• Pond
• Recirculating Tanks
Cage• Use existing bodies of water• Very inexpensive• Easy to harvest• Can move cage to fresh water• Fish can escape or be stolen/released• Problems with pollution and depleted
oxygen• Used for sea species, salmon, trout*,
bass, catfish
Raceway
• Need constant flow of water
• High water quality
• Expensive Construction
• May need waste treatment system
• Easy to harvest & maintain
• Catfish, bass, trout, eels
Pond
• Most common method
• Large scale production
• Need Aeration
• Harvest is difficult
• Shrimp, catfish, striped bass, sunfish
Recirculating tanks
• Uses least amount of water• Best temperature control• Fish can’t escape• Easy harvest• Lowest water quality• Highest energy costs• Ornamental fish,• Tilapia, catfish
Recirculating Tanks
• Main Tank
• Bio Filters
• Sediment Tank
• Pumps
• Water in/out control
Main Tank
• Holds fish
• Creates circular water pattern
• Collects from the bottom
• Removes Sediment/waste
Biofilter
• Bacteria (Nitrosomonas & Nitrobacter) cling to plastic discs
• Bacteria control the Ammonia• Takes 4-6 weeks for colonization
• Ammonia →Nitrite →Nitrate• NH3 & NH4
+ →NO2 →NO3
• Most toxic → Least toxic
Sediment Tank
• Has a cone shaped bottom
• Non-soluble solids settle out
• Soluble solids – give the water a brown color – need special filters
Sand filter
• Removes solids
• Sand clogs quickly
• After 4 months– No longer functional
Aquaculture Tanks
Equipment
• Biofilter – plastic substrate that bacteria can cling to.
• Bacteria convert toxic ammonia (NH3) in fish waste to nitrite (NO2) and then nitrate (NO3) which is least toxic.
Equipment
• Aerators keep the water circulating and keep oxygen in the water so fish do not suffocate.
Equipment
• Seines – nets with predetermined opening sizes to catch or hold only fish larger than a specific size
Equipment
• Live cars: temporary net for holding fish until sale or shipment
Shrimp Harvest
• Video