TRANSPORTATION OF LIVE TILAPIA
The development and expansion of aquaculture has made it necessary to transport live fish from one place to another, for various reasons. This movement of fish may be within the farm, between farms in the neighborhood or even between countries or continents. Fish can be transported at any growth stage and have a total survival by following some simple rules and devices as outlined below;
(A) PREPARATION OF FISH BEFORE TRANSPORTATION
The fish to be transferred should first be captured and held in a separate area, preferably in a hapa for at least a day before being transported in order to reduce stress since they will be easily be recaptured. They should also be not fed for this period to enable them empty their intestines before being transported so that they should not foul the water during transportation.
(B) WATER QUALITY
Tilapia as any other fish has to be transported in clean waters to ensure total survival. The following should be followed;
1.Water should be cool so that fish and bacteria will be less active, thus reducing the Dissolved Oxygen (DO) consumption and production of ammonia and Cabon dioxide. If possible ice can be added in the water to reduce temperature to 15 – 20 degrees celcius.
2 .The PH should be 7 to 7.5
3.The water should be free from mud and suspended solids to reduce fish stress and reduction of DO through decomposition. Preferably, well-water and rain-water are suitable for fish transport. Pond or canal water should be avoided because will deteriorate fast and hence stress the fish.
(C) DENSITIES OF FISH FOR TRANSPORTATION
This depends on the fish species, size and whether aeration is supplied or not. Tilapia are used to poor water conditions and they can be transported in a recommendable higher density.
(D) METHOD OF TRANSPORT
The simple and effective way of transporting Tilapia without continuous aeration is by using plastic bags containing approximately 20 litres of water and 20 litres of pure Oxygen. The fish should be transported at night or if it is during the day, the bags should be placed in a cardboard, wooden box or canvas bag to keep the bags cool and also reduce fish activity due to darkness hence reducing Oxygen depletion. The plastic bags MUST be doubled to minimize the risk of leakages. The fish can also be transported in a rigid metal or plastic containers with the aid of aerators. The system has proven to be more effective when the fish is being transported within the same locality and also with fingerlings and broodstock.
(E) STOCKING TRANSPORTED FISH
When the transported fish reach their destination, the fish in the container or bags should be gradually acclimatized to the quality of the water they are to be stocked because the temperature and chemical characteristics between the water may vary. If the plastics were used, the sealed bags should be floated in the receiving water for 15 -30 minutes in order to level out the temperatures, failure to do so may cause thermal shock to the fish and hence they may die. Finally, the bags must be opened and lowered in the receiving water and let the fish swim out freely. If the containers were used, then some of the receiving water should be slowly added to the container to equalize the temperature. After 15 minutes fish should be placed into the new water