Bell Work

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Bell Work

• What type of aquaculture system do we have
  outside?

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Types of Aquaculture Systems

• Area Animal Science
• Unit Aquaculture
• Lesson 7

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Objectives

• To identify the types of aquaculture systems.
• To identify the parts of an aquaculture system.
• To design an aquaculture system.

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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 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.

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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.

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What are the components of a recirculating system?

• There are 3 components to a recirculating system
• solids removal
• biofilters
• dissolved gasses.

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Fine Dissolved Solids Removal
Carbon Dioxide Removal Air Stone Diffuser Packed
Column
Fish Culture Tank
Aeration or Oxygenation Air Stone Diffuser Packed
Column Down-Flow Contactor
Nitrification Rotating Biological
Contractors Packed Bed Filters Expandable Media
Filters
Waste Solids Removal Sedimentation Screen
Filters Granular Media Filters
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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.