Bell Work
What type of aquaculture system do we
have outside?
August 2008
Types of Aquaculture Systems
Area: Animal Science
Unit: Aquaculture
Lesson #7
August 2008
Objectives
• To identify the types of aquaculture
systems.
• To identify the parts of an aquaculture
system.
• To design an aquaculture system.
August 2008
What are the types of
aquaculture systems?
• There are 5 types of aquaculture systems
– Pond Culture
– Canal Culture
– Cage Culture
– Raceway Culture
– Recirculating Systems.
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Pond Culture
• Ponds are earthen enclosures that hold
water.
• Most common way to raise fish.
– Easy design and low construction costs.
• Need large areas of land.
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Canal Culture
• Irrigation canals are also used to raise
fish.
• In areas where water is scarce, it is
good to have multiple ways to use
water.
• Divided into sections by nets or screens
• As long as no chemicals are placed into
the canals, they can be a great place to
raise fish.
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Cage Culture
• Cages are floating structure designed to
contain fish.
– Common in large bodies of water such as
lakes and oceans.
• Allow water and feed to freely float
through them and fish wastes to move
away
• Allow for easy capture of fish
• Cages come in various sizes and
August 2008 shapes.
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Raceway Culture
• Raceways are long narrow structures
where water constantly flows through.
• Typically used for trout.
• Allow for intensive raising of fish .
– constant flow of water.
• Typically raceways are setup in series.
• They require 5,000-10,000 gallons of
water to raise 1 pound of fish.
August 2008
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Recirculating Systems
• Recirculating systems use tanks and
filters to raise fish.
• Tanks come in a variety of shapes,
sizes, and materials.
• Usually several tanks are placed
together in a system.
• Need 5-10 gallons of water .
– Generally discharges 5% of its total system
water per day.
August 2008
August 2008
What are the components of a
recirculating system?
• There are 3 components to a recirculating
system
– solids removal
– biofilters
– dissolved gasses.
August 2008
Fine & Dissolved
Solids Removal
Aeration or
Oxygenation
Air Stone Diffuser
Packed Column
Down-Flow Contactor
Fish Culture
Tank
Waste Solids
Removal
Sedimentation
Screen Filters
Granular Media Filters
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Carbon Dioxide
Removal
Air Stone
Diffuser
Packed Column
Nitrification
Rotating Biological
Contractors
Packed Bed Filters
Expandable Media
Filters
Solids Removal
• Unused feed and fish waste can cause a
problem to recirculating systems.
– Rich in ammonia and require lots of oxygen
to be broken down.
• 4 types of solids removal systems
– Sedimentary tanks
– Screens
– Sand Filter
– Expandable Bed Filter
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Sedimentary tanks
• Allow for wastes to settle out of the water
to the bottom of the tank.
• The tank can then be drained of the solids.
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Screens
• Water passes through a series of screens.
• Particles are trapped in the screen mesh.
• Screen mesh gets smaller as it goes down
the line.
• They can then be removed and cleaned.
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Sand Filter
• Water passes through a pocket of sand,
gravel, or some other media.
• The sand captures particles as water is
pumped through it.
• Cleaned by backflushing the system.
– Water is forced through in the opposite
direction separating the particles from the
sand.
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Expandable Bed Filter
• Water is pumped through the sand from
the bottom.
– A coarser media above the sand which allows
for more particles to be trapped.
• To clean this filter, water is forced at a
higher pressure through the filter forcing
particles through the material and out a
drain.
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Biofilters
• Biofilters are necessary to remove
ammonia and nitrites.
– Tanks where fish are densely stocked, these
levels will get extremely
• 4 types of biofilters
– Rotating Biological Contractors
– Expandable Bed Filter
– Fluidized Bead Filter
– Packed Tower Filter or Trickle Filter
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Rotating Biological Contractors
• These filters rotate in the water allowing
for water to cover the filter.
• Also helps to stir and oxygenate the water.
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Expandable Bed Filter
• These filters are also good for the removal
of ammonia and nitrites.
• The coarse material in the filters give good
surface areas for bacteria colonization.
• These filters are hard to clean and are not
as commonly used in small systems.
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Fluidized Bead Filter
• Here beads are constantly turned within
the filter.
• Tends to have the same effects as the
RBC.
• Beads allow for a good surface area for
bacteria growth.
• Movement of the beads also allows for a
good exchange of gasses in the water.
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Packed Tower Filter or Trickle
Filter
• Uses a stack of biofilter material
– Allows water to trickle over them.
• Many different designs of these types of
filters.
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Dissolved Gas Control
• Oxygen, carbon dioxide, and nitrogen
need to be exchanged throughout the
water in order for the fish to survive.
• 2 ways to do this
– Surface aeration
– Diffusion aerators.
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Surface Aeration
• The surface area of the water is increased.
– Nozzles spray water onto the surface of the
water,
– Disturbs it allowing water from below to move
up
• Packed tower filters also do a great job for
this type of aeration.
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Diffusion Aerators
• Put air into the water.
– Oxygen contained in air bubbles will diffuse
into the water through the surface of the
bubbles.
– Many small bubbles are better than a few
large bubbles
• Diffusion aerators also move water in the
tank from the bottom to the surface.
August 2008