3.1.1 The public sector of aquaculture. The Department of Fisheries is responsible for the administration of this public sector (Sec. 2.9). It has also primary responsibility for the development of the private sector (Sec. 3.1.2).
The public sector presently consists of the Sagana Experimental Station (Central Province), the Kiganjo trout station (Central Province), and a series of demonstration ponds and small fish culture stations, particularly in Western Kenya. In Sagana, the experimental station was built in the late fifties at an altitude of 1 350 m for applied aquaculture research and the supply of fingerlings to fish farmers. To reach its production potential, it now requires renovation. The Kiganjo Station, built in 1960, functions mainly as a trout hatchery to produce the fingerlings needed to stock the local rivers for sport fishing (Table 17). A 300 t/yr production farm is soon to be established near Kisumu (Nyanza) with the assistance of the World Bank, as part of the Fish Farming Development Centre (Sec. 3.3.5). A pilot UNDP/FAO project in collaboration with the Department of Fisheries is presently establishing a 25 ha demonstration tidal farm in a coastal mangrove swamp, north of Malindi, for the production of penaeid shrimps, mullet, siganids and possibly tilapia (Table 16).
Aquaculture training of Government personnel is provided in various ways, according to education level. Senior personnel graduate from the University of Nairobi, where a limited number of aquaculture-oriented courses are available. Until now four cadres staff have been sent for training to the UNDP/FAO African Regional Aquaculture Centre in Port Harcourt, Nigeria. It is planned that from 1983 they will be also trained at the new Wildlife and Fisheries Training Institute in Naivasha, being now established with the assistance of the World Bank. Extension personnel receive some fish culture background in the Farmers Training Centres (Ministry of Agriculture), in areas where fish farming can supplement agricultural activities. Further aquaculture training possibilities should become available in the future Kisumu Fish Farming Development Centre (Sec. 3.3.5).
Aquaculture research has become a national responsibility since the collapse in 1977 of the East African Community. The Ministry of Regional Development, Science and Technology assures now overall supervision. Implementation is done by the Kenya Marine and Fisheries Research Institute (KMFRI), from Mombasa (Kenya Marine Research Laboratories) and Kisumu (Kenya Freshwater Research Laboratories). The need for aquaculture research in Kenya was emphasised recently in the Mombasa Symposium (July 1981) entitled “Aquatic Resources in Kenya: A Need for Research”. At this meeting, Balarin and Haller (1981) have, however, stressed the need for the immediate implementation of the results of past research through extension. The symposium also identified some of the shortcomings which have hindered aquaculture development in the past (Ochieng, 1981), further elaborated later in this report (Sec. 3.3.1).
Aquaculture research which has been successfully completed includes intensive brackish-water culture of tilapia (Balarin and Haller, 1981), the effect of organic fertilizers on pond fish (Oduo, 1981), the importance of static pond culture conditions (Wangila, 1981), diets for common carp and Clarias (Christensen, 1981a) and the breeding of Clarias (Christensen, 1981b). Meadows and Nyaga (1981) describe cage culture of tilapia in sewage treatment ponds and Ongoma (1981) emphasises the threat of fish parasites. Work on polyculture combinations are also underway (Ochieng, 1982).
The University of Nairobi has investigated the hormonal sex reversal of tilapia and currently it is considering the use of cages in irrigation canals (Table 16). The toxicity of rice pesticides to tilapia is also being tested by Mrs. Wangia (pers. comm., April 1982).
3.1.2 The private sector of aquaculture. The private sector is made of a few large-scale (over 5 t/yr) commercial fish farms and small-scale rural ponds belonging either to communities or to individuals.
The large-scale enterprises (Table 17; Fig. 14) are dominated by three trout farms, each with a production potential of 20 – 30 t/yr and all located on the slopes of Mt. Kenya and the Aberdare Range, in the Central Province. The Baobab Farm, near Mombasa, actually produces 25 t/yr of tilapia and 0.5 million fingerlings, using a highly intensive tank system. Apart from these four fish farms, three others with a present 5 t/yr potential are actively engaged in table fish production: Kilifi Sisal Estate, Mbingi Farm and Kaimosi Tea Estate. A number of other fish farms have been abandoned or neglected after a few years of difficult operation due to insufficient technological know-how, financial difficulties and/or poor site selection. As a result, the actual fish yield cropped from the existing large-scale farms may be estimated at 125 t/yr, of which trout contribute 75 – 100 t.
The small-scale rural enterprises are mostly producing tilapia at a subsistence level, using a low-input semi-intensive cultural system which includes some organic fertilization and supplementary feeds. As no reliable statistics are available, the total number of ponds involved varies according to authors. Official statistics propose 9 000 units, but a more realistic estimate would be around 4 000 – 5 000 ponds, of which 3 000 are located in the Lake Basin (Table 20). Each pond produces an average 13.5 kg/yr; the present rural production of farmed fish is estimated at not more than 70 t annually.
Most of these rural ponds belong to individual farmers, but some of them have been built recently by communities (e.g. church and school), with Government subsidies provided through the District Development Committees (DDC).
3.1.3 Selection of cultivated fish species in Kenya. The major fish species presently cultivated in Kenya are trout (Salmo gairdneri) and tilapia (Tilapia nilotica and T. zillii; T. spilurus in brackishwater). Other cultivated species (all exotic - Table 21) are, for example, the common carp (Cyprinus carpio), the black bass (Micropterus salmoides), the striped bass (Tucanare ocellaris), and the grass carp (Ctenopharyngodon idella). It has been recently proposed to also introduce the Chinese silver (Aristichthys nobilis) and black (Mylopharyngodon) carps, as microphagous and malacophagous species, respectively, (Anon. 1980).
It has already been recognized before that tilapia was not necessarily the best suited fish species to be cultivated in Kenya (FAO/UNDP, 1966). It has however never been clearly stated how one should subdivide the Kenyan territory into fish farming zones and how fish culture should be developed in each of these zones. Part of past failures most probably originate from this (Sec. 3.3.1).
It has been shown in Madagascar that the maximum potential yield of various tilapia species varies greatly according to altitude (Fig. 13). This relationship in fact represents the direct effect of water temperature on tilapia growth, the latter being progressively reduced as water temperature decreases, particularly below 20°C. Such relationship varies from species to species, T. zillii for example being relatively less susceptible to cooler temperatures than T. nilotica and T. aurea being known from Israeli experience as the best suited tilapia for fish culture in cooler climates. But in general, one should not for example expect a fish yield greater than 3 t/ha/yr when cultivating tilapia at altitudes ranging from 1 000 – 1 500 m. Maximum yields drop to 2 t/ha/yr at 1 500 – 2 000 m altitudes and above 2 000 m, if they can survive the cold temperatures, tilapia will practically not grow.
Large-scale fish farms in Kenya a
|Name and locationb||Date establ.||Species||Potential production|
|1978 to 1985||Shrimps Mullet Siganids|
|less than 25||Tidal ponds in mangrove||FAO/UNDP Project (25 ha) designed to demonstrate feasibility of coastal aquaculture|
|2.||Kilifi Sisal Estate|
|1979||Tilapia||5||3 m tank||A pilot scheme adopted by a sisal plantation with the intention to expand|
|1971||Tilapia Freshwater prawns||24–50 plus 0.5 million fingerlings||6 m tanks 0.5 ha ponds||Located in the disused quarry of a cement factory; a self-sufficient, highly intensive unit with its own research facilities. Produces seeds for sale.|
|1979||Shrimps Tilapia||5||6 m tanks||Pilot scheme which changed from shrimps to tilapia, but have experienced problems. Now abandoned|
|1982||Tilapia||5||0.5 ha ponds||Recently established with the assistance of Baobab Farm. Intends to use cattle manure|
|1978||Tilapia Clarias||5–10||Ponds||Semi-intensive operation with feeding, but have bad pollution problems. Now abandoned|
|7.||Sagana Experimental Station|
|1959||Tilapia Common Carp||5–10||Ponds 32 ha|
|Fisheries Department Experimental Station supplying seeds. Severe water leakages needing repair|
|1960||Trout||25||Tanks ponds||Fisheries Department Trout Centre for fingerlings supply to sport fishings; now also into table-fish production|
|9.||Tamarind Trout Farm|
|1979||Trout||25–30||6 m tanks||Imports eggs and grows fish up to table size and larger for smoking, for sale through Tamarind restaurants|
|1971||Trout||20–25||Earthern raceways||Has experienced siltation problems. Markets mostly through an open air grillroom on site|
|11.||Quality Trout Farm|
|1974||Trout||20–25||Ponds||Located in slightly warmer conditions, it has temperature problems in summer. All fish sold to airline catering agency|
|12.||Rowner Trout Farm|
|1968||Trout||5–10||Ponds||One of the earliest established trout farms. Now neglected|
|13.||Kaimosi Tea Estate|
|1976||Tilapia Common Carp||5||Ponds ab. 1 ha|
(0.2 ha max.)
|Pilot project utilizing sheep manure; located in cool area where tilapia production is affected by low temperatures|
|14.||Fish Farming Development Centre|
|(1983 to 1986)||Tilapia Common Carp Chinese Carps||300||Ponds|
|Pilot demonstration on unit to be built with IDA assistance. Extension, research, training, seed production|
|15.||Lake Jipe Sisal Estate|
|1948||Tilapia||50–100||Ponds 30 ha|
|Commercial farm, now abandoned for several years)|
a Individual potential over 5 t/year
b For location, see Figure 14
The above considerations provide the basis for subdividing Kenya into potential fish farming zones according to the distribution pattern of mean annual air temperature isotherms (closely related to altitudes - Sec. 2.2.2), as given by Survey of Kenya (1970). The country may thus be divided into four different zones (A - D), where the mean air temperature range gradually changes from 5 – 22°C to 22 – 34°C (Table 18 and Fig. 14).
Results suggest that at the most one-third only of Kenya's territory (Zone D) is well suited for warmwater aquaculture (including tilapia), subject to water availability. But this zone often includes arid conditions (northeastern Kenya) and remote areas (Turkana) or it borders a capture fishery (coast, Lake Victoria, Lake Turkana). Marginal areas (Zone C) where tilapia will not grow for 2 – 5 months of the year cover 52% of Kenya, where a semi-intensive technology would be more advisable. The rest of the country is suitable only for fish species better adapted to cooler conditions than tilapias, such as common carp and trout, although conditions may also be sometimes marginal for this last species for example during the warmest months.
3.2.1 The public and private sectors of aquaculture. In western Kenya, responsibility for administration and development of aquaculture has exclusively lain until very recently with the Department of Fisheries (West), based in Kisumu. Since 1980, some of this responsibility is shared with the newly established Lake Basin Development Authority who plans to recruit specialized staff (Sec. 2.9).
Presently the Department of Fisheries has in Kisumu a small fingerling production station, used for restocking Lake Victoria with tilapia. A larger station is to be built soon at Alum for the same purpose. Small fish-culture stations in Kisii and Kakamega have to be rehabilitated and several demonstration ponds have been built, especially in the South Nyanza District (Table 26). Total staff (Table 19) numbers 487 among which 122 fulltime fish scouts are assigned to law enforcement and some extension work, both for the capture fishery and for fish farming development. For the last two years, several U.S. Peace Corps Volunteers have been assisting with fish culture extension and in 1982 this aid has been increased (Table 16). Nevertheless, as shown by the average ratio of fish scouts per existing pond (Table 19), extension services remain minimum.
In the private sector, the large majority of the ponds are rural and belong to small individual farmers, only a small percentage of them being community property. One modest large-scale fish farm is operated by the Kaimosi Tea Estate (Kakamega District), using sheep manure and vegetable feeds in 0.2 ha ponds, to produce tilapia for local labourers (Table 17).
Following a Fisheries Department survey, it is estimated that about 3 000 ponds presently exist, representing only 35% of those recorded in 1973 (Table 20). Eighty percent of them are located in the Kisii (892), Kakamega (855) and South Nyanza (677) Districts.
The average production per surveyed rural pond is about 13.5 kg/yr (Table 22), which suggests a total annual production of about 40 t from small-scale fish culture in the Lake Basin. Present total production of farmed fish in this region, including large-scale enterprise, should not then be over 45 t annually, a little less than the Coûteaux (1981) estimate to be therefore considered as an upper limit (Table 11).
3.2.2 Fish farming zonation in the Lake Basin. As discussed earlier for Kenya in general (Sec. 3.1.3), one should also recognize different potential fish farming zones in the Lake Basin. It then becomes evident that only a small part of the Lake Basin (Zone D) is entirely suitable for warmwater fish culture (Fig. 14). This is the warmer belt surrounding the lake shore which probably coincides with the irrigated rice/sugar belt, as it is locally known to agriculturists. It further shows that tilapia culture is presently being practised and encouraged in the marginal Zone C, such as in the Kakamega and Kisii Districts at the border close to the more temperate fish farming Zone B. The Kaimosi Tea Estate (Kakamega District, alt. 1 675 m) provides a good example of this (Sec. 2.2.3). The water temperature ranges from 20 to 26°C (Fig. 8) and the tilapia production reaches 2.5 t/ha/yr at the most, being limited to the 7 – 8 warmer months of the year (Table 1). Preliminary tests with common carp obtained from the Department of Fisheries have given much better results (growth 200 – 300 g/yr) and this species will be used in higher proportions in the future.
Figure 13. Maximum potential yield of pond cultured tilapias according to altitude (modified from Balarin, 1979)
Characteristics of the potential fish farming zones in Kenya
|Zone percentage total||Common mean air temp. range, °C||Fish Species||System||Comment a|
|5–22||Trout||Tanks Cages Ponds||Good for trout production all year round. Caution essential during summer as higher temperature may be lethal.|
Central Province and Rift Valley
|10–26||Trout||Pond Cage||Production will be restricted to the winter period = 5 to 6 months per year|
|Common Carp||Any||Production may be all year round.|
|Tilapia||Ponds Cages||Very marginal zone as cold season limits growth 5 to 6 months per year|
Plains and Northern Province
|15–30||Common Carp||Any||Very good if seed available.|
|Tilapia||Ponds Cages||Adaptive to intensification with a 2–5 months non-growing period.|
|Catfish||Ponds||Good if seed available.|
Coastal and Lakeshore Belts
|22–34||Common Carp||Ponds||Very good conditions for the culture of all warm-water fish species in both fresh and salt water|
a Subject to local water availability
Figure 14. Potential fish farming zones in Kenya
Fisheries Department staff in the Nyanza and Western Provinces on 31 December 1981 (Acc.Dept.Fisheries - Western, Annual Report for 1981, in draft)
|Departmental Staff||Total number ponds|
|Ratio fish scout: pond|
|Cadres tech. staff||Admin. staff||Boat building/crew||Misc. subord. staff a||Fishery assistants a||Fish scouts/ranger a,b||Aid-Volunteers||World Bank Project Staff|
|Field enumerators||Market surveyors||Clerical||Miscellaneous|
(P.O. Box 1084)
(P.O. Box 104)
(P.O. Box 327)
(P.O. Box 700)
(P.O. Box 186)
|Total Lake Basin||29||11||-||43|
a Works-paid staff in parenthesis (casual)
b Combines fish scouts for capture fisheries and for fish farming activities as no further detailed data available
c See Table 20
Distribution of fish ponds in the Nyanza and Western Provinces
(Acc. Department of Fisheries records)
|% Ponds Currently Functional|
|A. Kakamega District||3 693||855b||60.9||446||20.6||1 569||23.2|
|Vihiga Div.||1 570||75||2.4||26||0.7|
|B. Bungoma District||664||171b||6.5||125||9.0||250||25.7|
|C. Busia District||427||146b||42.0||-||-||146||34.2|
|D. Kisii District||2 498||892c||21.2||-||-||892||35.7|
|E. Siaya District||270||292||290||108.2|
|F. South Nyanza District||1 122||677||677||60.3|
|G. Kisumu District||n/a||10||n/a||n/a||n/a||50||-|
|TOTAL||8 674||3 043||3 874||35.1|
a Fisheries Department “Ten-Year Report”, 1974
b Fisheries Department, Western Province - Fish Pond Survey 1981
c Fisheries Department Monthly Report - June 1981
d Fisheries Department Monthly Report - March 1982
e Fisheries Department Annual Report - 1980
Exotic fish species introduced into Kenya
|Lates niloticus||1959/62||Luwala Dam and L. Victoria||Uganda (L. Alberto)|
|Salmo trutta||1921||Highlands Streams||U. Kingdom|
|Salmo gairdneri||1910||Mt. Kenya||S. Africa|
|Cyprinus carpio||1969||Sagana Station||Israel/Japan|
|Ctenopharyngodon idella||1969||Sagana Station||Japan|
|Micropterus salmoides||1929||L. Naivasha||USA|
|Tucanare ocellaris||?||Sagana Station||USA|
|Macrobrachium rosenbergii||1981||Bamburi Farm||Mauritius|
|T. aurea||1977/78||Bamburi Farm||Israel|
|T. galilaea||1978||Bamburi Farm||Israel|
|T. andersonii||1980||Bamburi Farm||Botswana|
|T. macrochir||1980||Bamburi Farm||Botswana|
The annual mean minimum air temperature (AMMT) has been used in an attempt to define more precisely the fish farming zones in the Lake Basin (Fig. 16). From the lake shore towards the mountainous eastern borders, we find successively:
Zone D: AMMT greater than 16°C
Zone C: AMMT 14 – 16°C
Zone B: AMMT 10 – 14°C
Zone A: AMMT less than 10°C
It may be noted that the Sio (Busia District) and Nzoia (Siaya District) River valleys are particularly warmer. The eastern part of the Bungoma and the Kakamega Districts as well as the entire Kisii District belong to the more temperate Zone B. In these two last regions tilapia is not a suitable fish to be farmed as the main species and the combined use of a better adapted species, such as the common carp, should be considered. Tilapia should then become a supplementary rather than a priority species, to increase fish yields to a more acceptable level.