Productivity and marketing of Nile tilapia (Oreochromis niloticus) cultured in ponds of small-scale farmers in Mvomero and Mbarali districts, Tanzania

S W Chenyambuga, A Mwandya, H A Lamtane and N A Madalla

Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania.
chenyasw@yahoo.com

Abstract

A study was carried out to assess management practices, yield, marketing and production constraints of Nile tilapia (Oreochromis niloticus) grown in ponds of small-scale farmers in Mvomero and Mbarali districts. Information was collected through individual interviews of 46 and 40 small-scale fish farmers in Mvomero and Mbarali, respectively.

Most farmers owned one (54.2%) to two ponds (37.5%) and the average pond size was larger (631 m²) in Mbarali (P ≤ 0.05) than in Mvomero (345 m²). Most farmers cultured pure stand of Nile tilapia (79.3% in Mvomero and 89.5% in Mbarali) and only few farmers (20.7% in Mvomero and 5.3% in Mbarali) practiced polyculture of Nile tilapia and African catfish. In Mvomero district the majority of the farmers were fertilizing their ponds with goat and sheep manure (55.2%) while in Mbarali district the majority used cattle manure (89.5%). The frequency of manure application was either once per month (31.3%) or once per three months (37.5). All farmers depended on natural food as a source of feed for their fish. The majority of farmers were supplementing their fish with maize bran (94.7 and 96.6% in Mbarali and Mvomero, respectively) and kitchen leftovers. (26.3 and 20.7% in Mbarali and Mvomero, respectively). Average period from stocking of fingerlings to harvesting of Nile tilapia was not different in the two districts (P ˃ 0.05) and the overall average was 6.4 months. The average weight of fish at harvest was higher (382 g) in Mbarali (P ≤ 0.05) than in Mvomero (140 g) and the mean yield was 6,049 and 4,070 kg/ha per year in Mbarali and Mvomero, respectively. About 38% (Mbarali) and 46.6% (Mvomero) of the harvested fish were consumed at home and the remaining percent was sold. Most farmers sold fresh fish directly to their neighbours (86.2% in Mvomero and 73.7% in Mbarali). The major constraints to fish farming were irregular supply of water, predation, stunted growth of stocked fish, unavailability of fingerlings, and lack of concentrate feeds. It is concluded that the management practices in the two districts are generally poor characterized by improper feeding and pond fertilization. Productivity of cultured Nile tilapia is relatively higher in Mbarali than in Mvomero.

Keywords: constraints, feeding, fish farming, marketing, pond fertilization, yield

Introduction

In Tanzania aquaculture is dominated by freshwater fish farming in which small-scale farmers practice both extensive and semi-intensive fish farming. Fish farming is usually integrated with other agricultural activities such as gardening, livestock and poultry production on small pieces of land. Fish ponds of an average size of 150 m² are predominant under the small-scale fish farming system (URT 1997). It is estimated that there are about 14,100 earthen ponds (FAO 2012) scattered across the country, mainly in Ruvuma, Mbeya, Iringa, Morogoro, Kilimanjaro and Arusha regions. The dominant species cultured is Nile tilapia (Oreochromis niloticus), followed by African catfish (Clarias gariepinus) (Kaliba et al 2006). Other species used in aquaculture include milkfish (Chanos chanos ) and the flathead grey mullet (Mugil cephalus) which are cultured in the brackish and marine waters. The emphasis of the national fisheries policy (URT 1997) is on a semi-intensive integrated mode of fish culture, focusing on Nile tilapia. The Nile tilapia is given first priority due to its more desirable characteristics, including fast growth, short food chain, efficient conversion of food, high fecundity (which provides opportunity for distribution of fingerlings from farmer to farmer), tolerance to a wide range of environmental parameters, and good product quality (Hussain et al 2000; Neves et al 2008).  

In Tanzania aquaculture accounts only for a small proportion of total fish produced at the national level. However, aquaculture production provides vital animal protein to the people residing in areas which are located far away from the major fishery resources or where transport of fish is either difficult or too expensive. In some regions where protein intake per capita is low and where protein malnutrition prevails, the socio-economic benefit of aquaculture is high. Given the importance of aquaculture in the country, there is a need to improve fish production to complement the capture fisheries. Before embarking on improvement of productivity of fish farming, it is important to assess the production performance and economic profitability of Nile tilapia in ponds of small-scale farmers. This study was carried out to assess the management practices, determine the productivity and market channels of farmed Nile tilapia and constraints faced by small-scale fish farmers in rural areas. This information will help in developing appropriate improvement programmes aimed at improving the productivity of Nile tilapia in rural areas.

Materials and methods

Location of the study areas

The study was carried out in Mvomero district, Morogoro region, and Mbarali district, Mbeya region, Tanzania. Mvomero district is one of the districts in Morogoro region located between latitudes 8^o and 10^o south of equator and longitudes 28^o and 37^o east. The villages selected in Mvomero district were Langali, Tangeni, Mkindo and Komtonga. Mbarali district is one of the districts in Mbeya region and lies between latitude 7° and 9° south of the equator and longitude 33.8° and 35° east of the Greenwich Meridian. The district altitude varies from 1000 to 1800 m above the sea level. The villages involved in the study were Mbarali, Kongolo Mswiswi, Mambi and Ubaruku. 

Sampling procedures

A purposive sampling procedure was used to select two districts in which small-scale fish farming is predominantly practised. In each district four villages were purposely selected based on the existence of small-scale fish farmers who culture Nile tilapia. A total of nine to 14 fish farmers per village were randomly selected from the list of all small-scale fish farmers, making the total sample size of 40 and 46 households in Mvomero and Mbarali districts, respectively.  

Data collection method

A household survey was conducted and heads of the households were the main respondents. However, other members of the households were requested to attend the interview so as to supplement information. Face to face interviews of the selected farmers were conducted using a structured questionnaire and personal observation was also done. Both closed and open-ended questions were included in the questionnaire administered to the respondents. The questionnaire was designed to gather information on households’ socio-economic characteristics, pond size, fish management practices, production yield and marketing of Nile tilapia. In addition, information was collected on fish farming constraints. Also, the fish ponds of the small-scale fish farmers were observed visually and the physical conditions judged by the researchers.  

Data analysis 

Data from the questionnaires were coded and recorded into the spreadsheets for statistical analysis. The Statistical Package for Social Science (SPSS version 16.0) computer software was used to generate means and standard error for quantitative variables and percentages for qualitative variables. A t-test was used to assess the significance of the differences between the means of quantitative variables while chi-square test was used to compare the percentages of respondents from the two districts with respect to a particular response.

Results and Discussion

Socio-economic characteristics of the respondents

The characteristics of the respondents are shown in Table 1. The main economic activity in the study areas was crop farming, both in Mbarali (82.5%) and Mvomero districts (93.5%). The age of the respondents was not different (P ˃ 0.05) in the two districts and ranged from 19 to 86 years, implying that both young and old people are involved in aquaculture. But the majority (58.8%) of the respondents had the age of 40 to 60 years. This indicates that most of the people involved in aquaculture are of middle age and in the active working group. Young people (below 40 years old) and old people (over 60 years old) constituted only 21% and 20% of the respondents, respectively. The levels of education of the farmers in the two districts were not different (P ˃ 0.05). Most of the respondents interviewed had primary school level of education (81.4%), while 9.3 and 3.5% had secondary school education and tertiary education, respectively.  Generally, the literacy level in the study areas was relatively high as the majority of the farmers had the minimum education level. This is appealing because most of the farmers are able to read technology packages for fish farming. Most of the household heads were men (87.2%) and only few households were headed by women (12.8%). Furthermore, most fish ponds (43.8%) were owned by men and most of fish farming activities were done by men (54.2% of the households). Also men had more access to fish farming knowledge and income accruing from fish farming activities. This is because local customs and cultural practices in many communities in Tanzania make it impossible for a woman to own assets and land as these are acquired mainly through inheritance which favours men to women. The observation in this study with regard to heading the households and ownership of fish ponds is in agreement with the findings of Seki and Maly (1993) who reported that almost all fish ponds in Ruvuma region, Tanzania are owned by males, often the household heads. There were few women who owned fish ponds and most of these were widowed, divorced or unmarried women.  

Table 2 shows the characteristics of small-scale fish farming in the study areas. The average number of ponds per household in Mvomero was slightly lower (one to two ponds) than in Mbarali (one to four ponds). Similarly the average size of the ponds was lower (P≤ 0.05) in Mvomero (345 m²) than in Mbarali (631 m²). The lower number of ponds per household and the small pond size in Mvomero might be due to small size of land owned by farmers coupled with low knowledge on the importance of fish farming. Generally, most farmers in the two districts had ponds of medium size. The pond sizes observed in this study are higher than that of 150 m² reported by FAO (2012) and 150 – 300 m² reported by Kaliba et al (2006) in southern highlands and northern Tanzania. Most farmers in the study areas had ponds which they constructed themselves (95.8%) and depended on rivers (60.4%) as sources of water for their ponds, but few fish farmers were using water from the irrigation schemes (16.7%). The majority (83.3%) of the ponds were stocked with Nile tilapia (Oreochromis niloticus) and only few farmers practiced polyculture of Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus). In both districts the Nile tilapia was preferred to African catfish because of its ability to reproduce in the ponds and good carcass taste.  In some ponds the African catfish was stocked together with Nile tilapia in order to control recruitment of juvenile tilapia and allows the original stock of tilapia to attain a larger market size. According to de Graaf et al (1996) the African catfish is used as a predator to control unwanted/undesirable tilapia recruitment in ponds. The sources of fingerlings in the two districts were more or less the same (P ˃ 0.05). Most of the respondents said that they got their original stock of fingerlings from government institutions (37.5%), NGO/development projects (27.1%) and neighbours (25%). This might be due to the fact that most small-scale fish farmers were persuaded and encouraged by either NGO or research and development projects to establish fish farming enterprise.

Fish farming practices in the study areas

Management practices for pond cultured tilapia in Mbarali and Mvomero districts included only pond fertilization and feeding. Most of the small-scale fish farmers reported that they fertilize their ponds before stocking. The type of manure used to fertilize fish ponds was different (P ≤ 0.05) between the two districts. In Mbarali district most fish farmers used cattle manure (89.5%) while in Mvomero district the most commonly used manure was sheep and goat manure (Table 3). This is because cattle manure was readily available in Mbarali and could be obtained for free from the agro-pastoralists living in the nearby areas while the farmers in Mvomero had access only to sheep/goat manures since there are few cattle keepers in the study villages. Chicken manure was used only by few farmers (8.3%), despite the fact that almost every household kept chicken rather than cattle or goats. Chicken manure was not preferred because of the small quantity produced from chicken. The use of manure to fertilize ponds for tilapia culture is recommended in developing countries because fish farming is practiced at small-scale level, mainly by rural poor people who have limited capability to acquire commercial fertilizers and other inputs (Green et al 2002). In the present study most of the fish farmers applied manure to their ponds either once per month (31.3%) or once for every three months (37.5%). About 60 and 45.8% of the farmers in Mbarali and Mvomero, respectively, said that they put manure in cribs in order to fertilize the ponds slowly. The irregular application of manure observed in this study is consistence with the observation of El-Sayed (2008) who reported that small-scale farmers rarely adopt scheduled fertilization, instead fertilize their ponds with single application of 1.5 – 3.0 mt/ha of dry poultry manure.

Feeding of pond cultured Nile tilapia depended on natural food (43.8%) and concentrate (56.3% (Table 3). This is consistence with the recommendation of El-Sayed (2008) who said that natural food should be used during early growth stages, whereas supplemental feeds must be added at later fattening stages. Fish in a pond can live on natural foods like phytoplankton, insect larvae, worms, and other small animals. Unfortunately these natural foods are not always abundantly available year-round, hence, pond fish need to be fed with concentrate feeds. In the present study most of the respondents provided maize bran (95.8%), kitchen leftovers (22.9%) and vegetables/weeds (18.8%) as supplementary feeds to their fish. This is because these materials are readily available in rural areas and low in price. However, these supplementary feeds are of poor quality and this resulted into low productivity of the cultured fish. Fish cultured in ponds need to be supplemented with high protein concentrates. In the study areas protein concentrates such fish meal, soybean meal and oil cakes were not used for feeding fish due to the fact that their supply is irregular and most farmers cannot afford to buy them. Most farmers were feeding their fish either twice per day (52.1%) or once per day (33.3%). In tilapia culture the recommended feeding strategy is to feed a small but reasonable amount of feed at frequent intervals (Riche et al 2004). The optimum interval between feedings is 4 – 5 hours, depending on the energy and composition of the diet (Riche et al 2004).

Productivity of Nile tilapia in the ponds of small-scale farmers

Productivity of Nile tilapia in ponds of small-scale farmers is shown in Table 4. Most of the farmers in Mbarali stocked their ponds once per year (68.4%) while those in Mvomero stocked twice per year (65.5%). Average fish weight at harvest was about three times higher (P ≤ 0.05) in Mbarali district than in Mvomero. Consequently the estimated mean yield of Nile tilapia was higher (P ≤ 0.01) in Mbarali (6,049 kg/ha/year) than in Mvomero (4,070 kg/ha/year). The difference in yield is mainly attributed to the differences in management practices, including pond size and time interval from stocking to harvesting. The interval from stocking to harvesting was relatively longer in Mbarali (about 7 months) compared to Mvomero (about 6 months). The overall mean yield observed in this study (5,312 kg/ha/year) is higher than the yield of 2,089 and 4,704 kg/ha/year reported by Kaliba et al (2006) and Shoko et al (2011), respectively, but it is low compared to the yield of 10,000 kg/ha/year which can be achieved if improved strains and management are used (Eknath and Acosta 1998; Hussain et al 2000). The relatively low yield observed in this study is due to poor management characterized by irregular pond fertilization and poor feeding. In order to realize fast growth and, hence, big size at harvest, fish need to be supplemented with diet containing 25 – 35% CP. In the present study farmers in the study areas depended on pond natural food and were supplementing with maize bran which is low in protein content.  According to El-Sayed (2008) under small-scale farming system, where inputs are scarce, it is recommended to use a combination of regular fertilization and high protein supplementary diets. The farmers in the study areas neither practiced regular pond fertilization nor supplemented with high protein diets.

Marketing of pond produced Nile tilapia in the study areas

In this study the respondents reported that 42.3% of the harvested fish were consumed at home and the remaining (57.7%) were sold (Table 5).  Most of the fish produced by the small-scale fish farmers were sold and consumed locally. Table 5 shows that the majority of the fish farmers sold their fish directly to their neighbours (83.3%) and local markets (14.6%). Thus, the main market for cultured Nile tilapia were the neighbours of the fish farmers and this is because the quantity of fish produced was low and sufficient only to the people living around the fish farmers and local markets within the villages. This indicates that the market for the fish produced by the small-scale farmers is readily available within the villages and the quantity produced is not enough for selling to secondary markets and external markets. The prices of fish were not different (P ˃ 0.05) in the two districts and the overall average price was TZS 2,345 per kg. The observation in this study agrees with the findings of El-Sayed (2008) who reported that under small-scale fish farming in rural areas tilapia are generally produced for local consumption and their farm gate prices are relatively low. Most of the respondents sold fresh fish (81.3%) and very few sold processed fish (18.8%). The main processing methods in Mbarali district was frying (100%) while in Mvomero both frying (58.6%) and smoking (41.4) were practiced. This concurs with Kapute (2008) who reported that fish processing in Malawi is chiefly traditional and processing methods include sun drying and smoking.

Constraints to fish farming in the study areas

The results in Table 6 show that small-scale fish farmers in Mbarali and Mvomero districts were faced with several problems. The major problems reported by most small-scale fish farmers were irregular water supply (27.1%), predation (22.9%) and stunted growth of stocked fish (14.6%). Other minor constraints included unavailability of fingerlings, lack of concentrate feeds, inadequate knowledge on fish farming and theft. Studies by Brummett and Noble (1995) and Abiona (2011) have shown that high input price, price fluctuation, shortage of land, drought, lack of credits, poor roads, high transportation cost, theft and poor extension services are the main constraints to development of aquaculture in Africa. These challenges need to be addressed in order to improve fish productivity and make fish farming more profitable under small-scale production system.

Conclusions

This study has revealed that:

• The yield of Nile tilapia cultured in ponds of small-scale farmers is relative lower in Mvomero than in Mbarali.

  
  

• Most small-scale fish farmers fertilize their ponds with either cattle manure or sheep and goat manure once for every three months.

  
  

• Feeding of fish cultured in the ponds depends on natural food available in the ponds. In addition, farmers use maize bran as the main supplementary feed.

  
  

• The majority of the fish farmers sell fresh fish directly to their neighbours and consumers in the local markets.

  
  

• The main constraints to fish farming in Mvomero and Mbarali districts are irregular water supply, predation and stunted growth of stocked fish.

Recommendations

• Extension services for aquaculture should be strengthened up to the village level.
  
  
• Gender sensitivity training programmes should be conducted to increase women roles and extent of participation in aquaculture.
  
  
• More research is needed to develop improved strains of Nile tilapia and better quality and cost-effective fish feed rations from locally available feed resources.
  
  
• Efforts should be made to provide credits to small-scale fish farmers to enhance fish farming under small-scale production system.
  
  
• There is a need to establish fish farmers’ associations that will help the farmers to improve inputs availability and marketing strategies.

Acknowledgement

We acknowledge the financial support from NORAD through the programme for Enhancing Pro-poor Innovation in Natural Resources and Agricultural Value Chain (EPINAV) at Sokoine University of Agricultre, Tanzania. Moreover, we are grateful for the assistance provided by farmers and village extension officers during the undertaking of this study in Mvomero and Mbarali districts.

References

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Received 30 January 2014; Accepted 30 January 2014; Published 1 March 2014

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