Aquaculture



Aquaculture or aquafarming, is the farming of fish, crustaceans, molluscs, aquatic plants, algae, and other aquatic organisms. Aquaculture involves cultivating freshwater and saltwater species on farms or containters instead of wild harvesting.   Aquaculture products include fish, shrimp, oyster, algaculture, and seaweed farming. 

As loss of habitat, overfishing, and pollution has led to the loss of the number of fish and aquatic species in the world.  Due to this fact, some have started to farm fish, shrimp and other species.  This farming does many things.  It supplies fish, shrimp, oysters, etc for food and also to provide species for stocking.  This stocking will help replenish some species on the brink of eradication, and bring species to areas where not commonly found.  Both freshwater and saltwater species can be farmed.  

Freshwater is by the far the easiest species to raise and my personnel choice for aquaculture.  In this particular system, the fish, shrimp, etc grow in a container.  Their waste products in the form of feces, uneaten food, and urine are converted from nitrates, to nitrites, and utilized by plants for growth. The plants remove the ammonia and other chemicals from the water and the cleaner water is returned to the fish tanks. This system is useful for plant growth, because you do not have to add fertilizers and other chemicals to your system.  The fish supply everything the plants need.  I will discuss how I created my own system below.


How I made my small scale aquaculture system


You need: 


⦁ contains a large reservoir for holding the water and fish.  

⦁ A barrel or large bucket to be used as a stainer for waste removal

⦁ plant growing system such as drip, ebb and flow, NFT, etc

⦁ pvc or other pipe for moving the water through the system

⦁ bio balls or other multi surface material

⦁ water pump

⦁ air pump with air stones

⦁ electricity source

⦁ aquatic species you choose to raise.




The Reservior


The reservior can be any container such as a swimming pool, plastic tote, barrel, etc. that can be used to hold and raise the fish.  It must be large enough to adequately hold the fish from fry to adult.  It must be made of a material that is not toxic to whatever species your raising.  Larger containers also hold more oxygenated water and cause less stress on the fish.  It also dilutes the ammonia that comes from fish waste and keeps the water cooler.  So adjust the amount of fish you are going to raise accordingly.



Strainer or Waste Removal


Straining or waste removal is the most important part of this system.  It does exactly as its name implies.  There must be a syphon system set up in your reservior system to drain the waste and water into the removal system (see illustrations).  The water will drain into the bottom of a barrel or bucket.  Its best to create a swirl system to allow the waste to move around for easy drainage and removal if needed.  The waste will usually stay at the bottom and cleaner water will raise to the top.  Bio balls or other mulit surface material will then break down the nitrates the waste produces and change it to nitrites.  

There are two bacterial types that important in this system.  Both aerobic and anaerobic bacteria.  Aerobic bacteria must live in a oxygenated environment to survive and anaerobic bacteria lives in very little or no oxygen environment.  The bacteria eats the waste and converts it to nitrites.  Nitrates can become toxic to the fish over time, but nitrites are less harmful and plants love this form of nitrogen for growth.  An air pump must be used to add oxygenated air to facilitate aerobic bacteria breakdown plus is beneficial to both   In the lower part of the system the anaerobic bacteria will live and the air stone will be in the middle layer providing the aerobic bacteria the perfect environment to survive.  The upper layer is also where an water pump would be located to pump water to your grow systems.  



Grow System


The plants you grow in which ever grow system you want will further remove the nitrites and impurities in your water.  The cleaner water will then return to your reservior for your fish to live in.  Then the water and waste will just keep recirculating and repeating the process over and over again.  The system that utilizes this system best is the Ebb and Flow system, N.F.T. system, and water culture systems, but can be adapted to any system you want.  

Occasionally the older water would need to be partially drained and fresh water introduced to remove the toxic build up of chemicals from the waste and fish feed.  I usually do this twice a year , but can be done more frequently if desired.  



Water and air pump


The water and air pump is a much needed part of this system.  The water pump is used to circulate the water from your waste tank to your plants.  The size of the pump would vary according to the size of your system and your growing system size.  Another variable would depend on the drainage of the waste water from your reservior into your waste tank.  Too large a pump and your waste tank will drain to quickly decreasing the effectiveness of its actions. The returning water from your plant areas will also run back into your reservior tank to quickly and can cause it too overflow. Too slow and your plants growth will suffer.  One way to control and tweak the flow is by the use of ball valves.  Opening or closing the valve will safely control the flow of water to your plants, thus helping to alleviate the problems that arise.  

The air pump with air stones provide oxygenate air for the fish, bacteria, and plants to utilize.  All will suffer without it.  Air stones that produce small bubbles work best.  They will oxygenate the water more effectively.  Some people use soaker hose tubing to produce the small bubbles and is very cheap to buy.  But must be weighed down to be effective.



Aquatic species


A new aquaponic grower should decide on what species they want to grow according the amount of time and experience they want to devote to their system.  Some species are very forgiving like tilapia and catfish.  Species like trout, freshwater shrimp for example can be somewhat difficult without the right conditions.  Saltwater species are often difficult but can be grown, but do not reproduce in fresh water effectively or at all.  

I limit my systems to freshwater and tilapia or catfish.  Catfish is by far the easiest. They can tolerated very high concentrations of nitrates, low oxygen levels, and temperature variations.  Tilapia are very similar, but do not tolerate freezing or even cold water effectively, but do have a fast growth rate, better feed conversion, tolerate low oxygen levels,  and high nitrate conditions.  Each species has its own feed requirements and can be found or ordered at any Purina products store.


Warm water species like tilapia and shrimp will require warm water year round.  But heating water can get expensive, here is a link to a way to heat water cheaply.  Just click here



For additional info, click here


Aquaculture E-book

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