LVHD TILAPIA CAGE FARMING SYSTEM

BY: RONALDO B. GITANA

AQUACULTURIST

SAVANNA STREAMS, ZAMBIA

1. INTRODUCTION

       Tilapia is a cheap source of protein and popular food fish that has been pond farmed for thousands of years.  For instance the Ancient Egyptians farmed tilapias along the Nile. Today, tilapia farming is becoming popular around the world.

         Cage farming of tilapia makes it possible in bodies of water where draining and seining or harvesting would be difficult or impossible. Cages are for instance utilized in lakes, large reservoirs and rivers. They are also a good alternative for estuaries and coastal embayments, and have been successfully used for farming tilapia in cooling water discharge canals. The cages consist of mesh in order to let the water circulate freely.  Tilapias are among the most suitable fishes for fish Cage farming.

        Savanna Streams {an Aquacultural Business Endeavour; from production of quality seeds, pond and cage culture, feed manufacturing, EM (effective microorganism) production and extending technical support} are promoting Low Volume High Density (LVHD) Cage farming of Tilapia to benefit the small scale farmers, and village people to raise their own fish in Zambia. Savanna Streams also make low cost protein source available/accessible for the villagers.

II: WHAT IS LVHD FISH CAGES?

            Low Volume High Density fish cages are compact cage with a volume ranges from 1 cubic meter to 30 cubic meters, and can yield up to 100 kilograms of fish per cubic meter. LVHD fish cage farming was introduced in China in 1991, with remarkable success.

            The frame can either be made of HDPE pipe (in our case), bamboo, wood or steel bars, which are cheaper in the locality as long as the material is strong and durable. The netting materials should be made of nylon net provided with predator net at the outside.

III: ADVANTAGES OF LVHD FISH CAGES:

1. Lower investment cost-ideal for small scale farmers.
2. Easier to transport, set-up, maintenance and harvesting.
3. Close observation and monitoring of fish growth, health and feeding response.
4. Economical, and easy to manage for fist treatment of parasites and diseases.
5. Due to its compact volume, the water quality is always good, which promote a higher yield.

IV: DISADVANTAGES OF LVHD CAGES:

1. Depend totally on artificial feed.
2. Risk of loss from poaching, or damage by predators and of bad weather.
3. Greater risk of disease outbreaks if not manage properly.

V: PLACEMENT AND PROPER INSTALLATION;

            The LVHD cages should be well placed when the water current is strong, to maintain good water quality all the time.  Avoid stagnant water; it promotes bad water quality. Do not place the cages where there is always flood.

            Maintain a proper spacing between cages. To promote good water circulation, provide at least 5 meters space between cages. The cages must be installed at least 1 meter above the bottom, to discharge easily the waste of the fish. Installed them in a straight line configuration perpendicular to the direction water current to enable the frequent and unrestricted water exchange and maintain the good water quality.

VI: REMINDER:

            Avoid low temperature. The ideal temperature to achieve good growth is 28-30”C. The growth will dramatically decline when the temperature goes down to 20”C.  Tilapia will start to die at 10”C.  Please also note that a temperature below the optimum range will have a negative effect on the immune system of the fish. They might survive at first, but eventually will be susceptible to diseases.