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July 11, 2014

Preventing And Correcting Oxygen Depletion In Fish Farming

Preventing pond water oxygen reduction
Turn-overs occur when a pond is allowed to stratify or become layered because of temperature differences.
Prevent turnovers by checking oxygen concentration at bottom of pond and draining bottom layer when it becomes devoid of oxygen, or by using paddlewheel to break up layering before it can become a serious
problem.  
Oxygen depletions due to respiration - Thin out fish population by harvesting; reduce algae and bacteria population by flushing pond; or treat with chemicals such as potassium permanganate or copper sulfate. Use chemicals with extreme caution since they can make the situation worse.
Algae die-off - Reduce algae in pond by chemicals or by flushing, although it is extremely difficult to reduce an algae bloom by flushing. 

Correcting oxygen depletions 
Pump oxygen rich water from adjacent ponds) if available. Be careful not to cause problem in ponds) pumped from. This is the most effective way to provide oxygen to keep fish alive in a pond with oxygen problems. Don't cause loss of oxygen in water being pumped from an adjacent pond by splashing or
agitation.
Paddlewheel Aerators - There are many different designs but until recently there has only been limited research to indicate which is most effective at adding oxygen to the water and most economical in terms of cost per pound of oxygen added. Research at the Mississippi State University Delta Branch Experiment
Station has shown that a paddlewheel with a 20-inch drum is more cost efficient than one with a 4-inch
drum. Depth at which the paddlewheel is placed is also very important. Increasing paddlewheel depth from 4 to 14 inches tripled the oxygen transfer rate but only increased fuel consumption by about ½ gallon per
hour (see "For Fish Farmers," No. 83-2, dated April 29, 1983). The number of paddlewheels to use and the site in the pond where they should be located depends on the situation.
Crisifulli or relift pumps - most effective if discharge end is capped and the sides slotted to allow aeration of water. Well water usually has no oxygen and must be sprayed to aerate when being added to pond. Positioning of aeration equipment in a pond is critical. Place equipment in area where the oxygen concentration is highest. Be sure the fish are in this area and not trapped in another area of the pond. Also, be careful not to strand the fish by removing the aeration device before the oxygen is high enough to support them.

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Pond Aquatic Weed Control In Fish Farming

Methods

·  Mechanical control and evironmental manipulation. Mechanical methods may be as simple as cutting a willow tree or pulling or digging up a few objectionable plants that have just gotten started along the water margin. Mechanical methods also include using expensive and complicated underwater mowers. While cutting or removing a few plants by hand can be effective in small or limited areas, mechanical aquatic weed control on a large scale is generally useless. Environmental manipulation is usually a drawdown which is of little benefit in a catfish pond.

·  Biological control. This has been touted as the most promising form of aquatic weed control. Unfortuantely, biological control is still in the research stage and is not yet practical and safe for wide-spread use.

·  Chemical Control. Herbicides at this time are the most economical, safe, and practical means of controlling aquatic weeds in most cases. However, chemical control also has its limitations. Before you try any chemical control, you must accurately identify the aquatic weed, choose the correct and most economical herbicide, and the proper treatment rate. Accurately measure the water volume or surface area to be treated. MCES Information Sheet 673 gives procedures for calculating the amount of chemical to use and can be obtained from your County Agent. No control or inadequate control of an aquatic weed means that you selected the wrong chemical, used an inadequate treatment rate, chose the wrong formulation, or applied the chemical improperly. Excessive use of a herbicide, use at the wrong time, or use of the wrong chemical can create an oxygen depletion and result in a partial or total loss of all fish in the body of water treated. Any time aquatic plants are treated, oxygen levels should be monitored closely for 5-7 days, and you should be ready to use emergency measures to prevent an oxygen depletion from occurring.

ALWAYS READ AND OBSERVE LABEL PRECAUTIONS BEFORE USING ANY CHEMICAL IN AN AQUATIC ENVIRONMENT.

Steps To Follow for Aquatic Weed Control
1. Identify the problem weed.
2. Choose the most economical and efficient control method.
3. If you select a chemical method of control, be sure it is both economical and safe, as well as effective.
4. Calculate pond area and volume to be treated.
5. Follow label instructions.

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Removal Of Unwanted Species Of Fish In Ponds

Complete Eradication of All Fish
·  Drain and dry ponds.
·  Rotenone. Use 3 lb of 5 percent Rotenone powder, 3 pints of 5 percent emulsifiable Rotenone, or 6 pints of 2.5 percent emulsifiable Rotenone per acre foot of water. Insure adequate mixing. Results are best when water temperature is above 70°F (21.1°C). You can detoxify using 2 pounds of potassium permanganate for each pound or pint of rotenone used.

Selective Removal of Scale Fish
·  Antimycin A or Fintrol. Cleared for use in commercial catfish ponds by FDA.
·  Fintrol. The amount needed to effectively eliminate scale fish from a catfish pond depends on both the water temperature and pH. Check both before use. Usually the best time to apply it is early in the morning since the pH of the water is lowest at daybreak and is highest in the late
afternoon. For most economical results, use one-fifth of the recommended rate. By doing this, you can effectively and economically eliminate scale fish from a pond with no danger to the catfish. Fintrol is packaged as a liquid in two bottles; one bottle is the active material and one is diluent. They must be mixed in order for the active material to be toxic. Do not mix until just before use, and mix only the amount needed for the treatment, since it breaks down 24 hours after mixing.

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July 6, 2014

Big Fish Pictures: I want To Eat Fish Peppersoup O!

My post today is on a lighter note. Many people are addicted lovers of peppersoup. Please and please, you can also go into production. We need more hands to meet the expanding demands. If you don't produce, appreciate farmer who laboured to bring these sweet things to your table.

A friend of mine JuveFarms just shared these pictures on his profile.

My question is simple: How much fish can you eat??






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CONSTRUCTION OF “FLOW THROUGH” AND RECIRCULATORY FISH POND SYSTEM


CONSTRUCTION OF “FLOW THROUGH” POND SYSTEM
It could be completely or partially buried in the soil or a surface pond depending on the drainage pattern to be employed.

1.    Dig the foundation according to specification and then the footing.
2.    Lay one or two couches of block
3.    Lay the pipes
4.    Do the flooring
5.    Set other blocks (about 5 course is ideal) and set iron reds on every 2 course of  block
6.    Fill block holes with concrete, fill two courses at once.
7.    Reinforce with iron pillars at a space of 1m apart
8.    Plaster the pond inside in a double wall pattern (use 1 bag of water proof cement to a bag of cement)
9.    Plaster outside
10.    About 1.2m is ideal for pond height.
11.    Net the pond on top to prevent predation
12.    If your location is prone to flood, construct a complete reinforce concrete pond, not the one with blocks.

CONSTRUCTION OF RECIRCULATORY POND SYSTEM

 Same as above plus some extra features basically:
1.    Sedimentation Chamber – made of net or imported poly fiber or gravel and fine sand
2.    Biofilter – May contain plastics, polyfibres, empty crates, larva stones, oyster shell, etc
3.    Aeration chamber

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