CAGE CULTURE TRIALS IN RWANDA

I. INTRODUCTION

Cage culture of nile tilapia Oreochromisniloticus in Rwanda was first demonstrated in the early 1989. It was not until 2010, however, that commercial production of tilapia in cages started with very few cages in LakeRuhondo.The technology spread to nearly LakeBurera. Currently, there are about 400 cages in the two lakes.

Cage culture has provided an innovative approach for fish production in these lakes. It has improved the use of natural resources by increasing the number of small scale operators that can use this technology reducing therefore the total number of capture fishermen and the pressure of fishing against tilapia. It has also contributed to the increment of fish production in Rwanda.

As our human population continues to increase in the years to come, there will always be a pressing need for producing animal protein foods such as fish at low cost. With the availability of a domesticated fish like the tilapia for which its environment can be controlled, attaining national goal of self – sufficiency in fish production seems achievable and tilapia cage culture production data in Rwanda is very encouraging as fish production is concerned.

For further development of tilapia cage culture industry in Rwanda, three major areas are critical. These are:

1. The need for improvement of high quality fingerlings production and their regular availability

2. The commercial production of fish feeds for intensive culture and3. The technical enforcement of cage culture operators..

Each of the three areas mentioned above is as important as each other. However in time (chronologically), the availability of high quality fingerlings is the most essential to cage culture farmers. They are the basic input which enables repetition of the production and regular supply of fish seeds is necessary to support any viable aquaculture industry and its development.

Fish Food shortage is the other factor which is currently restricting the aquaculture industry in Rwanda. At present the only commercial fish food available to cage culture operators is imported from Uganda. The high cost of this imported commodity places it out of the reach of most small farmers and makes the food share of the fish production as high as 30% of the price of fish or of the production costs.

There is need for the nascent cage aquaculture industry in Rwanda to learn from successes and failures of cage aquaculture in Africa and elsewhere. Improved cage culture technology, information and knowledge should be disseminated among operators to improve their skills.

II. PRELIMINARY FINDINGS FOR CAGE CULTURE TRIALS IN LAKE BURERA AND RUHONDO

1. Type of cagesCage culture trials have been conducted on LakeRuhondo and Bulerera from 2010.The first set of 30 cages was installed at LakeRuhondo in July 2010 while the second set of 40 cages was installed at both LakesRuhondo and Burera in December 2010. Cages used for tilapia production in these lakes are floating cages made up by floating frames from which the net cages are suspended. The net cages have a mesh size of 15 mm and are of the same size of 2 x 2 x 2 m, making a total volume of 8 m3 per cage.Cages are then tied up per group of 10 cages to make a stronger structure. The stocking density is 25 fish /m3. Each group of 10 cages receives 2000 fingerlings weighing 20 to 30 g in average.

Figure 1: Design of Floating cage in Lake Burera.

The initial investment for cage operations includes expenses for nets, plastic drums and metallic/wood or bamboo posts for the framing of the cage. The investment includes also a guard house.The guard house which is used as a store is shared by all cage operators on site. That is the reason why its cost is not much as if it was built by each operator. The investment includes some equipment such as spoon nets, basins, balances and other small equipment necessary for fish handling. A total investment of 5 000 000rwf is required for a set of 10 cages of 8 m3 each.

2. Fingerlings supplyCurrently Tilapia fingerlings are only available through limited sources. Only one Government fish station supply fingerlings for ponds fish farmers, lakes and reservoirs fish stocking as well as for cage culture farmers. The government hatchery has potentiality to produce over 2 000 000 fingerlings per year yet this production is far below the demand.The current need for fish seeds of cages in lake Burera and Ruhondo equals 1 600 000 fingerling for the year 2012 without any expansion of cages. The price of a fingerling is subsidized and it is 11% of the price of fish.By the time being, the price of fingerling is not the crucial constrains of cage culture operations rather the availability of fingerlings at any time needed. For instance the year 2011, the demand of fingerlings was estimated at 1600000 for two production cycles. But only 140000 fingerlings (9%) were provided to stock 70 cages out of 345 cages present in the two lakes.Cage culture farmers must either produce their own seed or depend upon supply from other farmers being hatchery specialist or not. Increased consumption of tilapia will prompt rapid growth of tilapia culture industry and consequently increased demand for tilapia fingerlings. The involvement of private investors in tilapia hatcheries is crucial. With the full implementation of private tilapia hatcheries, fingerlings will be reliably available in large quantity, year-round, at a cost below 3% of the production cost without any subsidy. This supply of affordable high quality fingerlings will change dramatically the dynamics of cage culture farming. At the moment fingerlings are subsidized and cost of 220 rwf per fingerling. Stocking one set of cages costs 44 000 rwf.

3. Stocking rate.The stocking density of all cages in Burera and Ruhondois 25fingerlings per cubic meter (25 fingerlings/ m3). Each group of 10 cages is stocked with 2 000 fingerlings. The average size of fingerlings stocked varies between 20 and 30 g. This low stocking rate compare to what is being applied in other countries in Africa (200 to 300 fingerlings / m3) is due to the uncertainty of cage culture production in Rwandan environment. It is wise to start with low densities and improving it along with cage culture technology skills enhancement. Furthermore the problem of fingerlingsavailability will become more pronounced with the increase of the stocking rate.

The high mortality rate registered might have been caused by the sudden change of physico-chemical characteristics of water from hatchery’s ponds to the lakes environment. The Government fish station supplying fingerlings is situated at about 400 km away from the two lakes. In this area physic - chemical characteristics of water, temperature, pH, oxygen and any other water characteristics are different from those in the lakes. The mortality rate is high due to hatcheries that area located in different ecosystems than the final destination of fingerlings.

At the present any cage culture initiatives will be severely limited by the availability of fingerlings. Even if available, it takes more than three months to get them delivered due to logistics arrangements. Given the enthusiasm shown in cage culture production in the two lakes,investments in improved fingerlings supply that will be needed for small-scale cage culture operators to succeed; operators may need to develop their own hatcheries in the proximity environment.

According to available literature, the minimum recommended stocking density for tilapia is 50-80/m3. A recommended maximum stock density for beginning farmers is the number of fish/m3

that will collectively weigh 150 kg/m3 when the fish reach a predetermined harvest size. The smallest recommended fingerling size for stocking is 20 g. A 20 g fish will be retained by a 15 mm mesh net.

Stocking density calculation can be applied as the below equation:

4. Fish feeds.Supplemental feeding was distributed in the form of floating pelleted fish feed. This fish feed

is imported from Ugachick Poultry Breeders Limited in Uganda. This floating fish feeds come into the marketas 24%, 30%, 35% protein on an as-fed basis. Pellets are 2,3,4,5, and 7mm sizes.

The food was distributed daily. Some operators distributed once a day while some others distributed twice a day. The amount of food was adjusted according to the estimated biomass of fish present in each cage. The amount of food to distribute was 10% of fish biomass when the average weight of fish is less than 50g, 5 % when the weight is between 50 and 300g and 2% when fish weighted 300g and more. The total amount of fish feed distributed in each cagecage is shown in the table 1 below. Based on estimated amount of food distributed and the harvested biomass of fish, the average feed conversion ratio (FCR) which is the amount of feed required to produce 1 kg of fish is 1.85 (1.5 to 2). This means that it needs 1.85 kg of food to produce 1 kg of fish. This figure seems to be normal because the FCR in tilapia cage aquaculture systems in Africa is typically between 1.4 and 2.5. According to ugachickreports their fish feed has an FCR of 1.4.The higher figure of FCR of our trials may be the result of a miscalculation of the number of fish remaining in the cage due to the unrecorded mortality and therefore to the over-estimation of biomass present in cages. There is a need to review the sampling methodology and the mortality estimation approach. In our trials, the fish feeds accounts for 62% of the total production cost.

Obtaining good quality locally made feed is the second priority for commercial cage culture in Rwanda after quality fingerlings production. The main inputs for the fish feed production is the high protein fish meal which can be obtained locally by fishing the haplochromis, drying it and ground it to make fish flour. Besides the haplochromis flour, the additional important raw material inputs is soybeans, which can be produced by local farmers at low price. Until this fish food shortage is addressed with a locally manufactured product, the cage culture potential of Rwanda cannot be realized. This issue can fully be addressed in long run with the construction of a pelleted fish food plant. This will result in a locally produced, high-quality, affordable and standardized pelletized fish feed that is specific to raising tilapia in Rwanda environmental conditions.All raw materials will be locally sourced, and all labor will be locally hired with the exception of a foreign ex-patriot fish food expert in the early stages of the project. Once the fish food plant is fully functional, the operation will be fully staffed with local employees, creating yet more jobs. In a short term period however, as raw materials are available locally atreasonable prices, it is possibleto makea moist sinking feed on site by mixing different identified components. The availability of such a fish food not only allows the blossoming of the cage culture potential in Rwanda, but also other employment opportunities in the agricultural and non agricultural areas. One kg of the imported fish feed costs 900 rwf.

Table 1 : Preliminary findings for cage culture trials in lake Burera and Ruhondo

ParameterGroup 1

Group 2

Group 3

Group 4

Group 5 Group6

Group 7

Date of stockingDec 2010

Dec 2010

Dec 2010

June 2011

June 2011

June 2011

June 2011

Number of fingerlings stocked 2000 2000 2000 2000 2000 2000 2000

Average weight at stocking 20 25 22 26 30 20 22Average weight at harvesting (g) 472 480 478 500 542 470 474

Grow Out (Days) 192 183 185 187 190 199 196

Growth rate (GR:Kg/Day)* 3.1

2.5

3.0

2.6

2.4

3.1

3.0

Number of fish at harvest 1330 1048 1240 1066 960 1410 1332

Mortality rate (%) 33.50

47.60

38.00

46.70

52.00

29.50

33.40

Total biomass stocked (kg) 40 50 44 52 60 40 44

Total biomass Harvested (kg) 627.76 503.04 592.72 533 520.32 662.7 631.368

Fish biomass gained 587.76 453.04 548.72 481 460.32 622.7 587.368

Fish Feed distributed 999 906 988 962 921 1059 999

FCR** 1.7 2 1.8 2 2 1.7 1.7

*GR: The Growth rate is the total final weight of fish minus the total initial weight divided by number of days in the growth period**FCR: Food Conversion ratio is the quantity (Kg) of food required to produce one Kg of fish.

Group 1,2,3 :Stocked in Dec 2010- Harvested in July 2011

5. Grow Out

Two growth periods of more or less 6 months were observed. The first period started in December 2010 and ended in July2012 and the second one started in June 2011 and ended in December 2012. Both periods had a grow out of 6 months. Table 1 shows data related to these growth periods. The average grow out period is 190 days. It varies from 183 days to 199 days for the 7 groups of cages. The production average production per cage is 579.4 kg. The highest production recorded is 662, 7 kg while the lowest is 503 kg. The specific growth rate (SGR) which is the average final weight of fish minus the average initial weight divided by number of days in the growth period varies between 2.4 to 3.1 with an average of 2.8 kg of fish mass increase per day per cage.The growth rate gives us an idea on how the used tilapia strain adapts to the new environment

The optimum fingerling size for stocking in cages is determined by the length of the growing season and the desired market size.the shorter the growing season, the larger the fingerlingsmust be at stocking time.The use of male populations which grow at twice the rate of female populations will result in larger fish, greater production. The best size of harvesting should be around 400 – 500 g/fish as per the choice of Rwandan main consumers. Duration of the crop could be around 6 - 7 months. So in Rwanda cage culture farmers could get up to 2 crops a year.

6. Survival rate/ mortality rate.This is in connection with the explanation given above on mortality rate. The survival rate in

all cages is low (54.4%)due to the high mortality (46%) recorded at stocking time. It is thought that this high mortality is due to two main factors. The first one may be transport of fingerlings from the supply station which is about 400 km from the cage culture sites.The second reason may be the change of the growing environment. Fingerlings are grown in the southern part of Rwanda, an area which is warmer than the Northern part of the country where the cages are situated. The sudden transfer of fingerlings in these different environments may be the factor of this high mortality. Save this: cages with higher survival rate are logically the more productive with productions of more than 600 kg of fish per cage. Cage culture literature reports that the survival rate in smallholder tilapia cage culture is typically in the range of 70-80%, though survival rates as low as 60% have been associated with stocking densities in excess.We must find means of reducing this stocking mortality rate to less than 20%. It can happen if the Burera /Ruhondo cage culture operators are supplied from a nearby hatchery located in similar environment.

7. Harvest and MarketingThe preferred size for fish in Rwanda market is between 400 and 500 g. With good

management, it is expectedtoreach this size in 6 months. Sale prices vary according to size of fish. Fish weighing more than 500 g are sold for 3000 rwandanfrancs (5 US $) per kg, fish weighing 300-500 g are sold for 2000 rwf ($3.3) per kg. Fish weighing less than 300 g are difficult to sell and if they are sold it is at a cheaper price. There are mainly sold per pieces or they are consumed by the operator’s family members.

8. Cage culture farms Ownership

Cages are owned on cooperative basis. In the early stages of the operation (project) cages were supplied to the farmers on an initial no-cost basis. After the first growing season and harvest the farmer Cooperativesare expected to purchase other sets of cages to expand the operation. By running everything through the co-op, farmers will be certain to position themselves in the market and getting the best price for their fish. Also by allowing the farmers to concentrate their efforts on rearing the fish with the technical and logistical support of the cooperative, it is expected that the quality of fish can and will be optimized within the first year of operation. This will also ensure that there are adequate fish being produced to create an export market. With the vast water resources available, the ready supply of a good quality fish seeds and a huge market nearby in RDC there is no reason why Rwanda could not develop a huge export Tilapia industry.

9. Profitability of the operation.Fixed costs:As mentioned above, the fixed cost for cage operators are related to the investment of the platform of cages, equipment purchase, guard house and storage construction. The total investment cost is estimated at 500 000 000rwf per a set of 10 cages.Cages and guard house are amortized over 4 years.

Variable cost:Variable costs are related to fingerlings, feeds andlabor cost. Cost of Fingerlings, fishfeedand labor has been calculated and their amounts are shown in the table 1. Regarding labor costs, tilapia cage farms are usually family operated. Hired labor is employed only for cage construction and installation. Some farmers hired laborers to guard their cages. In the average, the total labor input per farm per 6 months is 104 man-days. The most labor intensive activity requiring 60 man days, is guarding the cages (6 months x 30 days/3 cage farmers). Another intensive activity in cage culture operationsis feeding and maintenance of the cages that required 42 man days (2 hours/day x 7 days /week x 4 weeks/month x 6 months). Harvesting and marketing count for 2 man days. A casual laborer works 8 hours a day and he is paid 1000 rwandan francs. The labor cost equals 104 x 1000=104 000 rwf.

Table 2: CAGE CULTURE PRODUCTION COSTS PER GROW OUT CYCLE

Parameter Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7Fingerlings cost rwf 44000 44000 4000 44000 44000 44000 44000Amount of food distributed 999 906 988 962 921 1059 999

Cost of food 899100 815400 889200 865800 828900 953100 899100

Labor cost rwf 10,400 10,400 10,400 10,400 10,400 10,400 10,400

Total variable cost 953500 869800 943600 920200 883300 1007500 953500

Table 3: Economical analysis of cage culture in Ruhondo and Burera Lakes

Item Cage 1 Cage 2 Cage 3 Cage 4 Cage 5 Cage 6 Cage 7Fixed costs rwf

500,000.0

500,000.0

500,000.0

500,000.0

500,000.0

500,000.0

500,000.0

Variable costs rwf 953500 869800 943600 920200 883300 1007500 953500Total Costs rwf 1453500 1369800 1443600 1420200 1383300 1507500 1453500Biomass harvested

627.8

503.0

592.7

533.0

520.3

662.7

631.4

Revenues rwf

1,883,280.0

1,509,120.0

1,778,160.0

1,599,000.0

1,560,960.0

1,988,100.0

1,894,110.0

Gross Income rwf 429780

139320 334560 178800 177660 480600 440610

Table 4:Production cost, revenues and return to investment per grow Out periodPer cage culture farm of 10 cages,

Item Group 1 Group 2 Group 3 Group 4 group 5 Group 6 Group 7Cage amortization 5 000 000 5 000 000 5 000 000 5 000 000 5 000 000 5 000 000 5 000 000Fingerlings cost 440000 440 000 440 000 440 000 440 000 440 000 440 000

Feed cost 8991000 8154000 8892000 8658000 8289000 9531000 8991000

Labor cost 104,000

104,000

104,000

104,000

104,000

104,000

104,000

Total costs 14535000 13698000 14436000 14202000 13833000 15075000 14535000

Revenues 18,832,800.0

15,091,200

17,781,600

15,990,000

15,609,600

19,881,000

18,941,100

Returns 4297800 1393200 3345600 1788000 1776600 4806000 4406100

CONCLUSION AND RECOMMENDATIONS:

Cage culture in Burera and Ruhondo Lakes shows encouraging perspectives for the future. The level of production achieved so far can be improved a lot by simply improving the techniques of cage culture technology.

Three areas are however of concern. These are the availability of fingerlings, the provision of quality and affordable fish feed and the technical capacity building of cage culture operators. The problem of quality fish seeds and their availability could be solved by involving private fingerlings suppliers to complement the existinggovernment hatchery. The problem of fish feed which is the most acute problem could be solved by producing the food locally. It possible by scaling down the Kampala technology and setting up small scale fish feed production plants. Raw materials for high protein food are available with the provision of fish meal from haplochromis. The development of haplochromis capture fishing can avail as much fish flour as it is needed to cover cage culture farmer’s needs. In the two lakes it is possible to produce more than 1000 tons of fish per year. This target is achievable and we shall make it.

Extension and capacity building The cage culture industry needs well trained extension personnel to support the development of a sustainable industry in Rwanda. There is need to build capacity of existing personnel and develop new capacity building programs at all level that will focus on training personnel to ensure sufficient skills in environmental regulation, cage culture technology development and business development facilitation and management. It is also essential to develop capacity of local institutions, private companies in business development services provision to the cage culture industry.

Research.There is a need to enhance growth data collection by improving the sampling methodology and systematically collecting monthly measurement. This will significantly affects

profitability by reducing feed wastage, increase feed conversion efficiencies and maximize growth.

N° COOPERATIVE LAC NOMBRE DE CAGES

01 KOAKI RUHONDO 1002 ISUGI RUHONDO 1003 COOPELRU SUGIRA RUHONDO RUHONDO 1004 COOPEGIFRU BULERA 505 COOPERUS BULERA 1006 KFCO BULERA 507 DUKUNDANE BULERA 1008 COPEBU BULERA 1009 CPLB BULERA 510 COVEPK BULERA 511 GUBWANEZA BULERA 1012 TWONGERUMUSARURO BULERA 1013 COOPESEKA BULERA 1014 COPEGALARU BULERA 1015 CODEPEGIRU BULERA 1016 COUMURU BULERA 517 COOPERU BULERA 518 TERIMBEREKAREREMBA BULERA 1019 INDERABUZIMA BULERA 1020 AMAJYAMBERE IWACU BULERA 521 KUAFI BULERA 1022 COOVEPOGA RUHONDO 523 COOPEGI RUHONDO 1024 COODEPE BULERA 1025 GIRAMAFI BULERA 1026 ECOPRORENA RUHONDO 1027 DUSABANE BULERA 1028 TWONGERAMAFI BULERA 1029 KO.NKU.KI BULERA 530 ATA BULERA 531 COOPEGA RUHONDO 532 TURWANYEBWAKI BULERA 1033 RUHONDO BEACH RESORT GROUP RUHONDO 1034 JYEJURU MUHAZI 2035 SUSURUKA RUHONDO 1036 GARUKA UREBE RUHONDO 1037 ABIYUNZE TURWANYEBWAKI RUHONDO 1038 COOPELACBU BULERA 10

39 STEPS DUFATANYE RUHONDO 10TOTAL 345

1 to 3: Cages units installed in December 2010 4 to 39: Cages units installed in 2011 195 cages in Burera ; 130 cages in Ruhondo and 20 cages in Muhazi: Total: 345