The purchasing of good quality young fish (fingerlings) is an important aspect of successful freshwater fish farming. Buy from properly managed hatcheries, enquire from other farmers, and make sure to buy healthy fish.
The following points are guidelines: Determine the selling price beforehand and compare with other fish suppliers. Inspect the general appearance of the fish, number of individuals, general sizes and age. Make sure all weighing and calculations were done correctly because you will pay the supplier per kilogram fish loaded.
The total mass and number of fish are important for future growth prediction and calculations of feed conversion rate (FCR). The FCR is the unit of feed used to produce a unit of fish meat. Monitor a sample of 100 to 200 fish for approximately one week.
If no negative response is noticed, the rest of the fish can be stocked. This procedure will help to evaluate the water quality of your dam and minimise the risk of losing fish when the dam is fully stocked. Reach an agreement with the supplier on the method and terms of payment.
Transport of Fish to Grow-out Sites
Prepare the necessary equipment and also prepare the fish for transport. Continuous monitoring during transport is very important to ensure the welfare of the fish and that it will arrive in good condition. Pay attention to the following: A permit from the official nature conservation office in your province is required for the transport of fish.
This has to be obtained at least 14 days before the planned transport, advises Henk Stander principal technical manager of Aquaculture: Department of Animal Sciences at Stellenbosch University. Check the weather forecasts a few days before transport. In warmer weather additional care is required with the transportation of fish.
Inform the hatchery at least three days in advance to get well-conditioned fingerlings to stock your pond. Fingerlings should have been conditioned before transportation. This means they are not fed for at least 24 - 48 hours. This makes it possible for the hatchery to select the fish in the best condition.
Transport equipment can be rented from commercial farmers. Carry an extra oxygen tank for emergencies and ensure all equipment is in good working order. Oxygen tanks can be rented from commercial farmers or from gas suppliers such as Afrox.
Load the transport tanks according to suggested densities: 1.0 – 1.2 kg of fish per 10 litres of water. Determine the oxygen levels and the condition of the fish in the tanks after it has been loaded and just before the transport of the fish begins.
Ensure that the oxygen tubes are not obstructed by the heavy tanks; 1000 litres of water weighs 1 ton! Inspect the tanks every 20 - 30 minutes during transport. The fish must be energetic and move around with ease. Make sure the oxygen levels and the water temperatures are within limits.
If the fish appear tired or are lunging at the water surface for air, then oxygen levels might be low and additional oxygen has to be released into the water. The driver of the transport truck has to make sure that the tyre pressure is correct and should drive cautiously at all times.
When arriving at the dam, try to maintain a balance between transport tank water and the dam water, in terms of temperature and chemical composition, by mixing 50 % of the tank water with dam water. Do not pour the fish straight into the ponds. Acclimatize fish first for a few hours and gently release them into the dam; mid-morning or late afternoon is best. After the fish have been stocked, wait at least 12 hours before the first feeding and monitor the fish closely for the next 24 - 48 hours.
By Marinda Louw