Aquaculture fish farming in Uganda is a rapidly growing and highly profitable sector driven by declining wild catches.

The most common systems adopted by farmers are earthen ponds, concrete tanks and lake cages primarily focusing on Nile Tilapia and African Catfish.

However for farmers to realise good harvest there is need to have access to quality fish seed which can be acquired by practicing good hatchery management practices coupled with feeding the fish with quality feeds.

This was the key topic discussed during this year’s Aquaculture fish farming Expo that took place at the Aquaculture Research and Development Centre Kajansi.

Background

Aquaculture fish farming research in Uganda is spear headed by scientists from Aquaculture Research and Development Centre which is part of the National Agricultural Fisheries Resources Research Institute (NaFIRRI) in Jinja.

The team on yearly basis organises Aquaculture fish farming Expo for farmers across the country at the research centre sensitizing farmers on various topics.

The director of the Centre Dr Papius Dias Tibihika explained that this year’s Expo was organised under the theme “Strengthening Market- Oriented Aquaculture Research for Spurred Agro industrialisation covering topics such Fish seed production and fish hatchery management practices.

Others are Fish feed formulation, production and management, fish health management,  Aquaculture business planning, record keeping and enterprise budgets, Aquaculture production system design and value addition in farmed fish.

He explained that every year the Institute with development partners organises Aquaculture Fish farming Expo at the Centre for farmers across the country with an aim of sensitising them to acquire best skills in managing their fish farming to earn better income.

The event attracts fish farmers from across the country and Seeds of Gold managed to catch up with the scientists for an interview focusing of fish seed production and management, below are the details.

The director general National Agricultural Research Organisation Naro who was represented by Dr Sadik Kasim the Deputy Director General Agricultural Technology Promotion explained that Uganda’s fisheries is at a turning point as it feeds millions of people in country.

This means agricultural research in this area must be conducted to increase fish production volumes to meet the growing demand as well as attract income to those dealing in the sector

He cites a challenge of limited volumes of fish fingerlings which is aimed not only for fish farmers in the country but for export as well-meaning research in fish genetics is important for the improvement of quality fish fingerlings to increase fish yields.

Other areas of importance are climate systems where farmers must adopt the technology of recirculation systems in aquaponics because less water is used to breed fish.

In the next five years, Naro intends to improve seed hubs to supply fish seed across the country, develop post-harvest technologies in order to obtain quality fish and train farmers on best practices in a bid to increase fish production.

To him let the Expo be more that exhibition but for farmers to learn better ways of aquaculture fish farming.

Fish seed production and fish hatchery management

Research assistant at the centre John Bolingo Metal explained that for fish farmers to smile all the way in fish farming to earn better, the process starts with scientists providing quality fish seed to attain good yield.

This therefore starts with the scientists conducting research by carrying out selection of quality parent stock which is used to breed the fingerlings.

Brood stock Management

He notes that healthy, mature and disease-free adult fish are the foundation for fish seed production and this can apply for both Nile Tiplapia Species and Cat Fish

The team usually acquires the parent stock from the natural waters and for the case of different species of Nile Tilapia, they are obtained from Lake Victoria, Albert and Lake George. Crosses of these species are done to obtain superior fish species which will be bred to obtain quality fingerlings.

In the case of improving single fish species, the team may decide to obtain Nile Tilapia from Lake Victoria in Jinja and collect another one from Lake Victoria in Kisumu and crosses are done to obtain a superior species.

This is because the same fish species are growing in different environmental zones and conditions.

Thereafter breeders are placed in dedicated, nutrient-rich brood stock ponds or tanks where they are fed high-protein diets to encourage gonadal maturation which is egg and sperm development.

Spawning & Fertilization

In the case of Nile Tilapia males and females are typically stocked together in controlled breeding environments often fine-mesh hapas placed inside a pond or tank

The fish mate naturally and females brood the fertilized eggs in their mouths until they hatch into fry.

Catfish require induced breeding through hormone injections where Ovaprim or pituitary extracts are removed because they rarely spawn naturally in captivity.

Once induced, females are carefully stripped of their eggs, which are then fertilized with milt collected from sacrificed males and this must be done form 10- 12 hours others the process may abort

Incubation & Hatching

Fertilized eggs are transferred to specialized incubation systems such as jars, funnel-type incubators, or flow-through troughs.

Constant water flow and oxygenation are maintained to prevent fungal infections and ensure the eggs hatch safely into yolk-sac larvae

Larval Rearing & Nursery

After hatching, the larvae subsist on their yolk sacs for a few days before becoming swim-up fry.

The Fry are highly vulnerable and require frequent feeding with micro-diets, high-protein powdered feeds, or live foods like Artemia tiny insects or rotifers scaled appropriately to their small mouth size.

For tilapia, fry are often fed a diet containing a hormone during the first few weeks to ensure they develop as all-male populations. Males grow significantly faster and prevent unwanted overpopulation in grow-out ponds.

Water Quality & Biosecurity

Water is the lifeblood of a hatchery which means strict physical and chemical parameters must be maintained.

The key parameters are high dissolved oxygen, stable temperatures of 26-30 degrees Celsius for tilapia and low ammonia levels.

Hatcheries often utilize filtration systems to remove metabolic waste and prevent deadly bacterial or fungal outbreaks.

According to Bolingo after going through the process the team multiplies the pure lines which is availed to farmers.

The team has trained selected farmers across the country to contact the initial breeding. This is after availing them with initial seed to start the process.

Climate smart breeding and fish farming

Bolingo explained that, the genetics team have conducted selected breeding for fish Nile Tilapia and Cat fish which are capable of growing in very cold conditions in Kabale and hot conditions in Karamoja.

Farmers in these regions have been availed with the selected species which are different from farmer’s operation aquaculture fish farming in moderate temperature conditions.

Under climate smart fish farming farmers are encouraged to adopt aquaponics fish farming where they rare fish and grow crops especially vegetables. This is because the water used for rearing fish is recycled for the plants growth.

Quality fish feeding and value addition

Ms Egulance Ganda a technician at the centre dealing fish feed formulation explained that due to the scarcity of silver fish which used to be part of the fish protein, the team is now concentrating in breeding Black Soldier lava which is dried and mixed with other feeds.

The mixture may include Maize barn, soybean cake among others but the mixture content differs from Nile Tilalapia to Cat Fish.

For the case of young fingerlings, it is advisable to feed them with powdered fish feed mixture and the mature ones on pellets of different sizes depending on the size of the fish.

Ganda notes that the team has sensitized farmers to add value to the harvest fish in order to earn more than selling it fresh

A good number of farmer groups are now processing fish sausages and some are smoking quality fish using the fish Klin which was distributed to them by scientists from Agricultural Engineering and Appropriate Technology Research Centre (AEATREC) Namalere.

At the centre already the scientists are extracting fish oil and processing it. The product they say is medicinal because is packed with essential omega-3 fatty acids whose nutrients are vital for controlling inflammation, supporting brain function and promoting heart health.