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