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Maximizing opportunities: enabling climate resilient urban slum communities through backyard catfish culture using solar energy and insects

Strengthening urban food production system by piloting innovative catfish, solar & larval insect technologies in slum areas in Malawi.

Photo of Will Leschen
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The project aims to build climate resilience among slum dwellers by providing additional source of income and food, based on resources and opportunities available in their locations. Malawi, particularly Lilongwe and Blantyre, will serve as a pilot of a technology already proven to work in Nigeria and Cambodia to produce catfish in backyard small scale concrete tanks incorporating simple but proven solar energy and insect larvae production technologies. The successful models in Cambodia were set up initially with carefully selected individuals, mainly women, and working closely with a microfinance organization, which provided a loan for the commercial fish feed and fingerlings production for the 3-month cycle. Together, this accounts for 70% of the total running costs. This loan was then repaid after three months when the fish were harvested and sold in local markets and/or by the tankside to local neighbours. The systems were enhanced in Cambodia with the incorporation of simple solar panels. These provide lighting over the tanks at night for security and to attract swarm of flying insects which will eventually drop into the water and becoming food to the fish. The solar panel also provides water aeration during the day to improve water quality and allow higher stocking densities. We will incorporate simple bin production of black soldier fly larvae to enable the recycling of low value wastes for fish feed and collection of roof rainwater to supply the fish tanks.


The people who will benefit initially will be those who are involved in the pilot. They will benefit from additional income and supply of fresh fish after 3 months. We want to run the pilots twice every 3-month cycles to test the technology in two low income slum areas of Lilongwe and Blantyre in Malawi and assess seasonality issues. The participants and pilot areas will be carefully selected. With the insights gained, we will scale up the technology to other neighbours/interested households.


This idea is based on successes in low income urban Nigeria and now Cambodia where urban land access, security, space and proximity to markets gave these systems a comparative advantage. The higher than ponds concrete tank constructions will mitigate risks from the increasing annual flooding in Lagos and Abuja and protection from theft being located next to the owner's dwellings. Changing seasonal rainfall patterns have already been observed in both Lilongwe and Blantyre. This has made conventional pond aquaculture more problematic. The idea proposed here therefore is a realistic and achievable model for fish production in low income housing areas in Malawi's two major cities. We will partner in this venture with Umodzi, which is a successful Malawian development NGO we have worked with before and have experience in food production and associated value chains in periurban areas. In terms of design, such systems are easily constructed. In Cambodia, it costed around USD260 for a 2x4 x1M blockwork tank with a payback period of 2.7 years. Adding further blocks of such tanks using common walls allows for further economies of scale and increased profitability. This solution explores everyday opportunities available in slum communities to address needs for food and income. The resources used in the proposed system (energy, feeds, water and fish) will come from the locality. Only insights from other countries are imported but tailored to the context of Malawi, and potentially other cities in the developing world.


  • Yes, for two or more years


  • I’ve worked in a sector related to my idea for at least two years


  • Yes


I work at the Institute of Aquaculture University of Stirling in Scotland. I have 20 years working in aquaculture development in developing African and Asian countries including presently the Aquaculture Enterprise Malawi project. I was a VSO volunteer in Ghana for 4 years working on aquaculture.


This is not a new idea or system having been developed in Nigeria originally 20 years ago as similar small periurban backyard concrete tank systems in Lagos & Abuja. These then developed with strong entrepreneurial spirit over 20 years into a fully blown industry & the country now at 180,000MT per year being the largest catfish producer in Africa. Stirling have been involved with catfish in Africa for a number of years ie Dr Kim Jauncey in catfish feed nutrition in the 1990s, Anton Immink working with a catfish producer in Uganda, one of our MSc students doing their thesis project there. Also currently we have a Nigerian PhD student doing his thesis research in Nigerian on Clarias broodstock development. This year I have been involved in a World Bank consultancy in 2 provinces in NE Cambodia where these backyard tank systems are now beginning to develop particularly being run by female urban dwellers integrated with irrigated vegetables and small scale solar.


Where this idea is essentially different is that it is completely unproven in an urban context outside Nigeria. In Malawi & elsewhere across Africa there are traditionally small scale urban producers of poultry & pigs who have proven business models. This system & associated value chain can be differentiated positively in a number of ways from these ie: 1. It is far more environmentally friendly in an enclosed urban space in safely recycling nutrients into irrigated vegetables 2. Whilst per kg of fresh fish /protein produced it has a smaller water footprint than chickens & pigs. 3 Much lower disease risk 4 It is incorporating low cost solar & black soldier fly technologies to further enhance profitability. For advantages: Clarias is an ideal fish for live transport thus can be transported & sold to other outside markets for higher prices. We have in our team a former Zimbabwean commercial fish farm manager, rare to find such expertise in Malawi, who is already working on a Scottish funded Aquaculture Enterprise project around Blantyre - We also have strong contacts with Blantyre Municipal Authority & urban planners who are keen to take this up


In terms of unknowns & as such potential risks we need to be well aware and go on to prototype at pre implantation stage : 1 If markets for these live Clarias will develop - Currently they are not available in inner city Malawi. 2. Security issues in such lower income crowded areas theft can be big issue - We will prototype and test different security devices with the tanks - eg metal mesh frames padlocked covering tanks - security can make or break this project. 3 Local commercial feed supply Is it good enough quality to produce good growth & FCRs at price the business plan can accommodate? 4 Will there be any cultural issues producing black soldier fly in inner city areas?


In terms of absence of any similar urban fish production in Malawi & /or supply of fresh live fish to inner city lower income persons: 1Malawians completely unaware of success story from Nigeria 2 They dont realise that it can be additional income earning activity to fit in with other daily activities 3 Govt Fisheries Dept totally unaware of this production model & still (along with outside donors) try to develop rural fish production far from lucrative urban markets. Also they have poor/no selection procedures for identifying small numbers of special entrepreneurial individuals. Would also add still difficult for such people to access affordable microcredit to start up


Feedback over last 2 yrs concerning feasibility of urban backyard catfish systems from Aquaculture Enterprise farming tilapia farmers in areas outside Blantyre. Subject discussed at workshop with 20 of them. Comments included: How much to set up tanks? Could they be made from cheaper materials wood? Will there be enough fingerlings to stock them regularly? Will need planning permission (bribes!) to local authority.? For this application I asked my two colleagues Abudala Napuru (AEM) & Tione Kaonga (Umodzi) to carry out quick informal interviews with potential uptakers in Blantyre advising them these people should be entrepreneurial, involved in some form of small business (food production/service ?) in low income urban areas. Feedback from these were: 1 Mr Masasa 47 from Chilomoni suburb of Blantyre. Agro dealer & rears pigs at his house. He said “Urban catfish farming could be good business venture since other business requires a lot of money to invest in & loans from the local banks are very high.” 2 Mrs Maggie Ndovi 39 from Blantyre involved in catering sector. Willing to rear catfish she said "I dont eat catfish but my family do. Wouldn't have trouble selling I would smoke them" 3 Mathias Chileka 52 fish trader Limbe market "Wouldn't mind but Im renting, landlord wouldnt accept" Finally Tione met Dr Alfred Chanza CEO for Blantyre City Assembly Open to the project but wanted more info on Nigerian systems health issues, disposal of waste water?


See Evolution of catfish systems in downtown Lagos. Note example husband & wife hairdresser (team) starting off two small tanks then growing During the project, the aim is to get 15-20 entrepreneurial Malawian urbanites to demonstrate financial feasibility of systems & associated value chains. Then for them to act as working examples for others to take up & then look to form urban "clusters" supporting each other - reduced micro-credit & feed costs -bulk buying also develop mutually beneficial value addition (smoking) & marketing networks, going on-line like Nigerians to search for more lucrative prices.


Not sure what this section is for...... - But if I was an evaluator on this general call I would ask the following question...... If you /your project was going to be working in an inner city slum area of a city which other local or national organisations and or individuals outside of the projects specific area(s) of expertise do you think you would have to engage and work with in order to make the project and its beneficiaries successful

How does your idea connect to the broader system of the city where you plan to implement?

As mentioned already in responses to some of the evaluators questions - we would be linking to some of the better quality fish farmers in the Aquaculture Enterprise project in order to develop new opportunities for them to become successful financially viable catfish fingerling producers. Outside of "aquaculture" through our local partners Umodzi we would be able to develop training and linkages in small business development and particularly market and input value chains in the two Malawian cities. The solar technologies required to develop tank lighting, water pumping and aeration - we would look to work together with another Scottish govt funded Renewable Energy project run in periurban areas of Blantyre by University of Strathclyde, Scotland. We have also already started consultations with the Blantyre Municipal Authority who appear keen to run with this project. We will do likewise with their counterparts in Lilongwe


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Photo of Will Leschen

Dear Chioma
thank you for your questions - please see responses below :
1. What is the robustness of the supply of fingerlings?
Clarias gariepinus (African catfish) fingerlings are not widely available presently in either Blantyre or  Lilongwe however  we have a very experienced hatchery manager  Abudala Napuru in our team (former Lake Harvest, now Aquaculture Enterprise Malawi  ) who will initially be able to produce the  necessary fingerlings we require for our 15-20 pilot uptakers . Interestingly  catfish female broodstock of 1kg & above  each produce up to 15,000 eggs  - therefore with just the stripping of  2 female  catfish and one male Abudala  will more than  be able to produce enough fingerlings for all 15-20 pilot outgrowers -  each will require  800-1000 fingerlings to stock  one of their  4 X2 X1 concrete tanks. Abudala   will be able to  do this every three months after each  production cycle of the pilot outgrowers.  Within  the project  we intend also to  carefully select at least  two  local fish farmers with promise & appropriate skill sets for Abudala to mentor & train
in fingerling  production so that when the project moves from pilot to roll out stage these new catfish hatchery producers will have  a new business opportunity to supply the increasing numbers of concrete tanks  in the two cities
2 The size of the market for fish? This is not an issue  or problem  as currently  there are few if any traders selling  live catfish  in the urban/ periurban markets of Lilongwe  or Blantyre - so will have an  open market to sell. Primary feedback  you have seen already shows that local women in catering trade see no problem in selling  & also  indicate that they can also arrange for fish to be smoked - there is already well established market for wild  caught smoked catfish.  We don't  foresee  the market  chain as being a   potential bottleneck for this project  - rather the opposite - with considerable unfulfilled demand especially for  live  fresh   catfish in  inner city areas. For uptakers getting  optimum price will be key for their  financial viabilities and  future growth.    
3 No  aeration ? That is the beauty of this fish species - African catfish can withstand very low dissolved oxygen DO levels in the water - in fact  they don't actually  need aeration to survive - However the reason we provide aeration is because higher DO levels   mean catfish will feed more each day - If they feed more  then they will grow  more quickly & bigger in 3 months, thus  the ongrower will make more money
4. Water Temperature  - Again African catfish very resilient to higher water temperatures up to 33  degrees  C . There is  some seasonal  variation in temps  in  Lilongwe & Blantyre & its  likely to have more  of  an effect on the catfish with lower  water temps from  July to September
5 How does the business plan stack up - would it be possible for a person to set up this business without subsidy through existing credit organisations - would this be an attractive option for people?  Yes it may be possible for  certain persons living in Blantyre /Lilongwe to set up   one of these concrete tank systems - however  they  would be few & individuals who already had access to loans and were trusted  by credit  providers. However for most  and  especially those lower income persons ( and also men) living in urban areas  they would just not have any chance  of getting  even a small loan for  this type of business start up .  I think also even very entrepreneurial lower income persons  who  could borrow the necessary funds to start this up would be very wary if  they didn't have any  support & provision of  technical information, advice & regular mentoring  visits   from experts who knew how to make these systems profitable - That is  why in  this project we will  include one Nigerian private sector partner to provide this  hands on technical knowhow,  therefore south south  cooperation & knowledge exchange within this project. Thus the decision making process to go ahead will not just be affected by  provision of competitive loans  at lower interest rates - it  will  also be very much  be reliant on the project providing hands on regular  technical advice and monitoring - from people who  have already built & run these systems before for profit
7. What has the failure rate of farms set up in Nigeria been ? What were the causes of failure (eg disease, theft, other ?). Nigeria is now 20 years along the road from the original beginnings of these systems - thus there  has already been an evolution  in how  the  systems have been developed & who is  best to do this.  The less efficient and  less entrepreneurial individuals  have already  fallen along the wayside  due to a nos of reasons  as you mention - failure to prevent theft, non regular feeding, poor tank  management, lack of sales skills - in the end as stated before successful fish farmers are special people with  specialised skill sets.

Photo of Phil Anselmo

Hi will. Do you have a module on how to grow african catfish in a tank. Can you help me where should i start. What should i do. Thanks. Hoping for your response

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