August 2008 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.

August 2008 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.

August 2008

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.

August 2008

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.

August 2008

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

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

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 Nitrification Rotating Biological Contractors Packed Bed Filters Expandable Media Filters Carbon Dioxide Removal Air Stone Diffuser Packed Column

August 2008 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

August 2008 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.

August 2008 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.

August 2008 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.

August 2008 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.

August 2008 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

August 2008 Rotating Biological Contractors These filters rotate in the water allowing for water to cover the filter. Also helps to stir and oxygenate the water.

August 2008 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.

August 2008 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.

August 2008 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.

August 2008

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.

August 2008 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.

August 2008 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.