Transcript Bell Work What type of aquaculture system do we have outside? Types of Aquaculture Systems Area: Animal Science Unit: Aquaculture Lesson #7

Bell Work
What type of aquaculture system do we have
outside?
Types of Aquaculture Systems
Area: Animal Science
Unit: Aquaculture
Lesson #7
Objectives
• To identify the types of aquaculture
systems.
• To identify the parts of an aquaculture
system.
• To design an aquaculture system.
What are the types of
aquaculture systems?
• There are 5 types of aquaculture
systems
– Pond Culture
– Canal Culture
– Cage Culture
– Raceway Culture
– Recirculating Systems.
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.
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.
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
shapes.
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.
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.
What are the components of
a recirculating system?
• There are 3 components to a
recirculating system
– solids removal
– biofilters
– dissolved gasses.
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
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
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.
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.
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.
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.
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
Rotating Biological
Contractors
• These filters rotate in the water allowing
for water to cover the filter.
• Also helps to stir and oxygenate the
water.
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.
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.
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.
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.
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.
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.