Hatchery and Fingerling Production

Credits: Biovision-Infonet

Although tilapia breed freely in ponds, it is important for farmers (producers) to consider using properly produced fingerlings. They need to invest in hatcheries for fry and fingerling production. Quality fingerlings in tilapia aquaculture are very important. For this reason it is advisable for farmers to generate their own fingerlings if they can not ascertain the quality of those from other sources. Poor fingerlings result in poor harvests. 

Developing a hatchery will allow the farmer to have ready fingerlings whenever he needs them. As long as the demand for fingerlings exists, a well-managed hatchery can turn out to be a good business.

Three methods of tilapia fingerlings production are commonly practiced in Kenya:

• open ponds (most commonly used)
• tanks
• hapas in ponds (net enclosures)

For these methods, fry are collected from the spawning units and stocked into fertilized ponds for rearing to the fingerling stage before they are stocked into grow out ponds.

Open Pond method

This is the simplest and most common method of tilapia fingerling production in Kenya. A properly constructed and well fertilized pond serves both for breeding and rearing fry. Brooders are stocked into the ponds and allowed to spawn naturally. The brood fish are stocked at the rate of 100 to 200 kg/ha at a sex ratio of 1:3 or 1:4 (males to females). A female brood fish of 90-300 g produces as much as 500 eggs per spawning. They should produce 6 – 15 fry/m²/month. To increase seed production, use larger brooders. Brooders of 1 – 1.5 kg can produce 45 fry/ m²/month. For this case, you need to harvest every 17-19 days. 

Harvesting fry from the ponds is done every 15 – 21 days or more frequently with water temperatures  above 25degC). The brooders can be used for 3 – 5 years. Fry harvesting should be done by hand scoop nets along the edges of the pond to minimize pond disturbance and fry mortality.

The Tank method

Tank-based hatcheries are relatively expensive to set up. The tanks should be circular in shape and can be made of concrete, plastic, fiberglass or even metal. The tanks should be 1-6 m diameter with a water depth of 0.5-1 m. Diet should contain 30-40% crude protein and daily supply at 1-2% of body weight. Fry can be collected every 10 – 14 days. Yields of up to 400-3,000 fry/m2/month can be realized using this method. Tanks are easy to manage but are relatively expensive to set up compared to ponds and hapas.

The ‘hapa’ method

A hapa is a cage like net impoundment placed in a pond for holding fish for various purposes. They are made of fine mesh netting material. The mesh size is such that the fry or fish inside can not escape. The ideal hapas is 3 m long, 3 m wide, and 1.5 m deep.

When using hapas to generate fingerlings, stock brooders should be weighing about 100 to 200 g at a ratio of about 1:5 to 1:7 males to females. Stock the brooders at a density of 4 – 5 brooders / m2. Hapas should be inspected for fry every day. Remove the fry using a scoop net after two week and stock them into tanks, other hapas, or in a rearing pond. Fry-production in hapas range from 150 to over 880/ m2/month. Fry should be fed 4 times/day until the fry reach the desired size (5 g). Use a diet in powder form at the rate of 5-10% of the total body weight per day

Production in hapas range from 150 fry/m2/month to over 880 fry/ m2/month. 

Feeding

Advantages of using this method are easy handling of fry ad brooders, a high production per unit, uniform fry of the same age, minimal losses and hapas can be set up in a pond with other fish.

Disadvantages of the hapa method tha it is more demanding than open ponds and tanks, mortalities may occur due to agressiveness during spawning, the fish has to be fed, poor water quality is likely due uneaten feed and fish waste and mesh will get clogged limiting water circulation and need periodic scrubbing. In stormy weather hapas can be destroyed and the material will degrade in sunlight and need replacing. Fish may easily escape from damaged hapas.

Disadvantages of the hapa method

• Management is more demanding compared to the other methods
• Mortalities may occur due to agressiveness during spawning
• Feeding is a must
• Hapas can be destroyed during stormy weather
• Hapa material will degrade in sunlight and need replacing 
• Fish may easily escape if the hapa is damaged
• Localised poor water quality is likely due uneaten feed and fish waste
• Hapa mesh will get clogged limiting water circulation and need periodic scrubbing