We have been working on setting up a recirculating aquaculture system to support tilapia farming, and currently we have been able to get a greenhouse like effect using a mix of wood panels with plastic pipes to get the warm environments. Next is to get pumps circulating the water and the filtration – both solid and bio-filters running before bringing the next batch of fry probably in March 2017.
As part of the expansion of the fish operations, the next phase is to improve the amount of control over the conditions within the ponds. Currently the water is only changed once in 3-4 days depending on the weather conditions.
The plan is:
- Setup RAS circulation with solid settlement and bio-filters (Ultra-violet light based)
- Setup a solar system to power the pumps moving the water
- Add a covering over the tanks to produce a “green-house” like effect to maintain the water temperatures in ranges that are ideal for tilapia
6 months down the road from when we started the aquaculture project, growing tilapia, this is our half year report card:
What Went Well
- There are now two tanks of 3000 (6 month old fish) and 6,500 (2 month old fry)
- Acquired fresh water testing kits to ascertain the quality of water at changing, however the team better understands how to use behavior cues like response to feeding, color of water to compliment the water testing
- Changed feed providers from Ugachick to Sabara feeds which provide better floating capability, at half the price and the fish seem to prefer them too.
What Did Not Go Well
- Bought too much initial feed – about 60kg due to recommendation from a sales agent at a feed supplier on later analysis found that they did not even understand the core numbers for the feed they were selling
- Initial tank design was using plastic sheeting with wooden poles – struggled alot with maintenance of the tank which was 27″ x 12″
- When we moved to concrete tanks, there were structural weaknesses in the construction that led to one of the tanks breaking fortunately with no injuries. The breakage also damaged the plastic sheeting tank forcing an emergency evacuation of all the fish.
- The day of the incident with the tanks, was the same day we had 10,000 new fry from the hatchery, so we had no choice but mix 4 month fingerlings with the fry together in a single tank. And the older fish ate the fry!!! Who can believe that Tilapia are cannibalistic – stress, cramped conditions may do that
What does the future look like
- Planning to purchase and setup a solar driven submersible pump to support aeration to improve stocking density
- Setup a third tank to help reduce the sell off cycle times
As always a couple of photos …
Feeding 4 month old fish in the new tank – May 2016
After a 1 month test of using polythene tanks with wooden supports which seemed lower cost at the beginning, we have decided to move to concrete tanks that surprisingly have a similar capital cost envelope with the benefit of longer life span.
The design of the tanks is:
- Bricks laid in header bonds (with the small face of the brick laid at the side)
- An reinforcing column every 6 feet on the short side and 10 feet on the longer side to provide additional strength
- A finer mix of the mortar used for laying the bricks (3 wheelbarrows of sand per 50kg bag of cement)
- Bottom was a concrete slab with a slight incline of the floor towards the outlet to help with cleaning
- The finishing includes an additional mix of water proof cement in a ratio of 1kg of waterproof cement per 50kg of regular cement.
- The outlet is placed 1 foot from the bottom so that not all the water drains out of the tank in case of accidental leakage
As always a picture is worth a thousand words:
The day began very early at about 5.30am with a fast drive to Ttomi, Buloba about 9km from Busega Round about to the Aqua Consults Fish farm to pick up a batch of 4,000 1 month old Tilapia fry.
The fry were already conditioned in their “brooder” pond, so just had to be collected and counted. The counting was an interesting exercise in estimation, as a sample was picked up in a sieve – then manually counted to provide a basis for estimating how many “sieves” were required.
Once the fry were counted, they were packed into polythene bags with about 5 litres of water which included salt to help ease the stress, and filled up with oxygen from a tank and then tied with rubber strips into an airtight container.
The journey to the farm site was a compromise between driving as fast as we could on a murrum road with road works and over shaking the fry which would increase stress.
Once we got to the site, we first placed the polythene bags in the tank for 15 minutes so that the temperatures would be consistent to prevent temperature shocks, then opened the bags for water to flow from the tank. The fry moved out of the polythene through the space of 1 hour.
The fry were not to be fed on Day 1, to give them time to adjust to their new environment
All in pictures … Happy 2016!!!
The fish tanks are almost ready, but what it brought back were ideas from opensource technology – release fast release often & test test test.
The story continues, after the initial construction of the structure, a base of sand was added to provide a smooth foundation on top of which was overlaid a 1000 gauge black plastic sheet to provide a cushion against stone damage to the water holding clear plastic sheeting. The sheeting is sold in rolls of 5′ x 150m, so 5 sheets had to be joined side by side to provide a 25′ width sheet to go across the tank, having 4 joints. Once the sheet was placed in the tank, we started pumping water into the sheeting, patching leaks as they were identified. It was a very tedious and slow process involving alot of manual labor.
Once that was done, the tank was filled to a height of 5′, it will never hold that much water, but it provided a stress or load testing opportunity which showed that some of the corner poles needed to be reinforced.
One that was done, all is well and the tank is holding on until the fish are to arrive ….
The fish farming project has now kicked off with the commencement of construction.
Phase 1 to be completed in 2015 shall include:
- Construction of two fish tanks using makooko (bark from trees) and treated poles (ebikonodo). The poles are placed 2′ apart in order to provide a strong structure against the weight of the water in the tank.
- Building of an overhead “green-house” like structure to help maintain the temperatures which fluctuate rapidly due to proximity to Lake Victoria
- Fencing of the area to keep out monkeys and monitor lizards which are abundant in the area.
The fish type to be reared in the tanks is Tilapia Esculenta commonly known as Ngege.
Progress is shown in the photos below: