Technical reports

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These reports present the findings of research or field studies conducted in the agricultural sector.

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Report of a Rapid Assessment of the Lake Nakivali Fishery
(National Fisheries Resources Research Institute (NaFIRRI), 2012-09-21) National Fisheries Resources Research Institute (NaFIRRI)
Lake Nakivali is a small lake, 14 km long, 6 km wide, 26 km2 in area and has maximum depth of 3.5 m at high water level (Hughes and Hughes, 1992). The lake is located in a lake-swamp complex with River Rwizi as the principle inflow, and a number of peripheral lakes among which are four major ones, i.e. Lakes Nakivali, Mburo, Kachira, and Kijanebalola. The indigenous fisheries of these lakes were based on Clarias gariepinus, C. werneri, and haplochromine cichlids until 1935 when they were stocked with Oreochromis spp (e.g. O. niloticus, O. esculentus and O. leucostictus) and other tilapiines e.g. Tilapia zillii and T. rendallii (Hughes and Hughes, 1992). Annual fish catches from Lake Nakivali rose to 655 t in 1960 and attained a peak of 986 t in 1964 but decreased to 174 t by 1966 (Vanden Bossche and Bernacsek, 1990) and further decline was noted around 1971 (Hughes and Hughes, 1992). This downward trend of catches both the native and introduced fish species appears to have continued to the present day but there are hardly any records of fish catches. Lake Nakivali is a controlled lake with four official landing sites, namely: Kikusi, Kahirimbi, Kashojwa and Rukinga. The latter three are located within a Refugee settlement whereas Kikusi is outside. The Nakivali Refugee settlement was established in 1963 for Rwandese of Tutsi origin but at present has at least seven nationalities which include people from Rwanda, Democratic Republic of Congo, Somalia, Sudan, Ethiopia, Kenya and Eritrea. The Integrated Rural Development Initiative (IRDI) project in Uganda which is promoting Community Based Environmental Management in Nakivali Settlement in Isingiro district, estimated that 43,448 people composed of 22,448 refugees and 21,000 nationals were living in the area (about 378 km2) in December 2006. The subsistence activities of this large population have had stressful impacts on both land and lake resources. The project seeks to correct this degradation and to support refugees and nationals in using the environment in more friendly and profitable ways. As part of this effort, and following concerns of low fisheries productivity and related environmental issues, the Office of the Prime Minister, through a project on refugee settlement proposed to assess the viability of stocking fish and watershed rehabilitation through tree planting in Lake Nakivali. The project management approached NaFIRRI’s for assistance in the following areas: 1. Assessment of Lake Nakivali for re-stocking and watershed planting; 2. Assessment of endemic species in the lake; and 3. Identification of possible Income Generating Projects (IGPs) for the locals and refugees.
Impact of Cage Fish Farms Operations on Socio-economic Activities of Surrounding Communities in Buikwe district.
(National Fisheries Resources Research Institute - NaFIRRI, 2016-06-11) Robert Egessa; Angela Nankabirwa; Hikmah Nabukenya
In Africa, subsistence-level pond-based system has been the focus since the 1950s, with cage aquaculture starting in the 1980s in sub-Saharan Africa. The benefits of cage fish farming include: poverty alleviation, employment, community development, reduction of exploitation of wild fish stocks, increase in fish supplies and export earnings for the country. However, cage operations also affect water environment and socio-economic activities of other resource users. NaFIRRI has been monitoring the water environment within and around cages but there is scarcity of information on impact of cages on socio-economic activities of surrounding communities. Since socio-economic elements are at the core of most developmental initiatives, a study was carried out in the communities (Bugungu, Busaana and Namusenyu-Buikwe district) close to established cage fish farms on Lake Victoria. The aim was to assess whether established cages are threatening fishing, navigation/transport, recreation, tourism, cultural services, or agricultural activities of the surrounding communities. Therefore, a cross-sectional study was carried out on households at or near landing sites close to cage fish farms. Data was collected from: capture fishers, navigators, farmers, fish traders, retail business (restaurants, bars, shops and other small business), local leaders as well as fish farms managers. Of the total (n=178) respondents, 57.3% were fishers, 1.12% were involved in shipping, 10% in crop or livestock farming, 23.6% were fish traders while 6.8% were involved in retail business (restaurants, bars, shops and other small business) at the landing sites. Of the total respondents (n=178), 59.5% (n=106) reported negative impact of the farms on fishing. Among these (n=106) respondents, 50 (47%) were from Busaana, 36 (34%) were from Bugungu and the rest, 20 (19%) were residents of Namusenyu. Complaints such as: cages reduced fishing space and restriction of fishers and navigators from operating close to cages by farms were reported in all the communities studied, with the severity of these impacts varying according to the locality and fish farm operation. Other perceived negative impacts such as: dispersion of fish making it hard to catch due to the use of what they termed “noise equipment” was reported in Busaana; while dispersion of fish by light from fish farms was reported at Namusenyu. Respondents also indicated to have benefited from some cage fish farms through buying fish and gaining income through part time jobs. These results suggest that fishing was the most negatively affected of all the socio-economic activities. It is important that farm management put in place all considerations agreed upon during the initial stages of the project to create trust and ensure cooperation with the residents of communities the farm is located.
Report on Environmental Monitoring of Cage Fish Farms at Mwena, Kalangala on Lake Victoria
(NATIONAL FISHERIES RESOURCES RESEARCH INSTITUTE (NaFIRRI), 2016-05-09) Robert Egessa; Angela Nankabirwa; Godfrey Magezi
Fish farming in cages generates considerable amounts of nutrient wastes (e.g., faeces, uneaten feed and metabolic excretions from fish) that are released into the water column, which may cause undesirable environmental effects. To ensure that cage fish farming develops in a more sustainable way, monitoring of water quality around cages is essential for generation of data from which decisions on environmental management may be reached. As part of the monitoring process, a survey was carried out on four cage fish farms at Mwena, Kalangala on Lake Victoria. Nutrient and phytoplankton samples as well as data on physico-chemical parameters were collected on 19th and 20th April 2016. The pH, DO, temperature and conductivity were measured in situ with a submersible multiprobe, CTD-90M (Sea and Sun, Germany). Water transparency and Total depth were measured using a standard Secchi disk and a hand held sonar respectively. Water samples for nutrients and phytoplankton were collected using a 3L Van Dorn water sampler, and analysed using standard methods. Physico-chemical parameters: pH (7.23 to 8.86), DO (6.99 to 8.92 mg/L), conductivity (100 to 102.4 μS/cm), temperature (24.18 to 24.830C) and Secchi depth (2.0 to 2.6m), around cages and the reference site were within the range for good water quality. The concentrations of ammonia nitrogen (5.02 to 11.18 μg/L), nitrite nitrogen (0.14 to 7.46 μg/L), nitrate nitrogen (75.68 to 189.36 μg/L) and soluble reactive phosphorus (10.92 to 20.62 μg/L) were within acceptable levels for fish farming. However, high levels of TN (>1mg/L), TP (>0.1mg/L) and SRSi (>1mg/L) were recorded both at the reference site and cage areas. The Chla concentration, indicative of algal biomass was relatively low, and ranged from 2.78 to 9.73 μg/L both around cage fish farms and the reference site. Phytoplankton groups: Blue- green algae, Green algae, Diatoms, Dinoflagellates and Cryptophytes were encountered. Blue-green algae dominated at all sites both in terms of bio-volume and species richness, with dinoflagellates showing the least number. Generally, the bio-volume was relatively low, although that within the cage fish farms was higher than away from the cages. These results suggest that there was negligible contribution of nutrients from cage fish farms; presence of other anthropogenic sources of nutrients in this part of the lake; and that other factors besides nutrients control phytoplankton biomass, abundance and species composition. There is need to collect more data over seasons in this part of the lake to capture nutrient variability of the system. Investigations on the direct or indirect effect of activities in the catchment, on this part of Lake Victoria are recommended.
REPORT OF LAKE WAMALA FISHERIES FRAME SURVEY 2012
(National FisheriesResources Research Institute (NaFIRRI), 2012-03-08)
Lake Wamala is one of the significant small lakes in Uganda after the five large lakes Victoria, Albert, Kyoga, Edward and George. The lake is located in central Uganda northwest of Lake Victoria and generally surrounded by numerous swamps and marginal vegetation and mashes. The lake lies between latitudes 0o 15'; and 0o 25' N 31o 45' to longitude 32o 00' E, longitude and at an altitude of 1000m above sea level. It varies in size both seasonally and over a long-term drought cycle, with a periodicity of up to 30 years. Lake levels were very low in early 1990’s but with El Nino rains of 1997, there has been significant improvement in the size of the lake and overall fish catches. It is indicated that the surface varies from 100 to 180 sq. km depending on the season. There are 6 rivers feeding this lake i.e Rivers Bimbya, Mpamujugu, Nyonzi, Kobusuma, Kibimba and Nabokazi. (Kaddumukasa et al. 2006). Following heavy rains in 1961 the open water of the lake expanded from about 100 km2 to 118 .km2 while the fringing swamps and islands covered about 60 km2. It maximum depth was 4.3 metres (Okaranon 1995). In the 1980’s this lake prevously was found in Mubende district and had 11 landing sites i.e Gombe, Katiko, Bukongo, Buteba, Karyonkoko, Kamuli, Luboja, Buzibazi, Lusalira, Mamba and Lunoni. An aerial count in October 1965 gave 450 canoes on the lake and up to 53 canoes were recorded in Katioko landing site alone (Okaronon 1993).Today the situation has changed the number of landings have increased due to population expansion around the lake.The communities around the lake purely depend on the system for their livelihood and poverty reduction in particular fishing besides livestock and crop production. Unlike other major water bodies of Uganda where period assessment of fishing factors is carried out to guide management, fishing effort and infrastructure on Lake Wamala have not been evaluated or reported for close to two decades. It was reported that one of the management problems of most African lake fisheries is that they are open access with no control of fishing effort (FIRRI, 2002). Poor management on any lake is partly attributed to lack of or inaccessibility of information on the types and size structure of fish available for harvesting, guidelines on the quantities of fish that can be harvested without depleting the stocks, suitable fishing effort and fishing gears and methods for exploiting the fisheries. Although Lake Wamala is an important system that supplies fisheries resources and significantly contributes to the economies of the riparian districts, a regular assessment of its fisheries has elluded management. Against the above background, the intervention provided by the Lake Victoria Environmental Management Project II, under the applied Research provided an invaluable opportunity to assess and report on the status of one of the satellite lakes of the eco- region.
REPORT OF THE FRAME SURVEY OF LAKE ALBERT CONDUCTED IN MAY 2012
(NATIONAL FISHERIES RESOURCES RESEARCH INSTITUTE (NaFIRRI), 2012-09-03) Taabu-Munyaho A.; A. Bakunda; D. Mbabazi; J. I. Nyeko; H. Nakiyende; E. Rukunya; S. Bassa; E. Muhumuza; M. Nsega; R. Amiina; J. S. Balirwa
Lake Albert and Albert Nile are a major source of fisheries resources sustaining the riparian communities in Uganda and the Democratic Republic of Congo (DRC). Like all shared bodies of Uganda Lake Albert and Albert Nile fisheries are faced with immense exploitation pressure one time described as the tragedy of the commons. In Uganda, the lake is shared by five riparian districts namely: Buliisa, bundibugyo, Hoima, Kibaale and Nebbi. The lake covers a total estimated surface area of 5,270 km2 with approximately 60% within Ugandan waters (Walker, 1972). It is located in the western part of the great rift-valley at an altitude of 618 m above Sea level. The central parts of the lake are characterized by steep escarpments whereas the northern and southern parts lie in a plain of the rift valley. The plains are gently sloping, resulting in shallow swampy inshore waters in many places. The major inflowing rivers are the Semliki and Kafu in the south, and the Victoria Nile at the northern tip. The lake has a diverse fish fauna with a gradient of multi-species fisheries in different parts of the lake. With funding support provided by the National Environment Management Authority (NEMA), a comprehensive Frame survey was conducted out by the Department of Fisheries Resources (DFR) and the National Fisheries Resources Research Institute (NAFIRRI) covering the Ugandan portion of Lake Albert and Albert Nile in May 2012. The frame survey captured the main characteristics of the fisheries and facilities supporting the fisheries and provides baseline information for reference of other studies as well as management interventions.
REPORT OF CATCH ASSESSMENT SURVEY OF LAKE ALBERT – ALBERT NILE CONDUCTED IN JULY 2012
(NATIONAL FISHERIES RESOURCES RESEARCH INSTITUTE (NaFIRRI), 2012-09-05) Taabu-Munyaho A; D. Mbabazi; H. Nakiyende; S. Bassa; E. Muhumuza; M. Nsega; A. Byekwaso; R. Amiina; J. S. Balirwa
A Catch Assessment Surveys (CAS) with the overall objective of generating information on the fish production and commercial value of the fisheries of Lake Albert and Albert Nile system was implemented by the National Fisheries Resources Research Institute (NAFIRRI) in collaboration with the Department of Fisheries Resources (DFR), Local Government staff (FOs) and BMU members at selected landing sites on Lake Albert (12 landing sites) and Albert Nile (26 landing sites) in July 2012. A total 622 and 313 boat days on Lake Albert and Albert Nile respectively were sampled for a period of 9 days. Results indicate an annual landing of 151,600 and 5,900 tonnes (t) of fish with an estimated beach value of 122.5 and 14 Billion (UShs) from Lake Albert and Albert Nile respectively. Over 80% of the catch from Lake Albert comprised the small pelagic species; Neobola bredoi (Muziri) and Brycinus nurse (Ragoogi) followed by Nile perch (6%). However, due to low market value of the small fishes and the high prices attached to Nile perch for industrial processing and export market, the contribution of the latter to beach value rose to 34% of the total. The contribution of the light fishery based on small pelagic species ((B. nurse and N. bredoi) are insignificant on Albert Nile. Even if the small pelagic species may be present in the river system, a light fishery based on these two is yet to be developed. Proportionally, Albert Nile still remain a multispecies fishery with over 20 fish species harvested commercially. Interestingly, the Albert Nile fishery still remains primitive with simple crafts and gears (mainly dugout canoes, traps, and gillnets). This could suggest that the more developed the system becomes the higher the level of transformation in its fisheries leading to simplification, characterized by reduction in multispecies nature and dominance of few species. Illegal gears especially undersized gillnet of mesh size less than 4 inches were the most dominant in the Lake Albert and Albert Nile fisheries. They captured large quantities of immature fish particularly when used to target Nile perch, Bagrus, Nile tilapia, and large Barbus spp. Their impact when used to target the smaller species (Ragoogi, Angara & Ngasia) is yet to be evaluated. A specific study to analyze selectivity and impacts of these nets is a recommended. However, the dominance of 1.5” mesh sizes especially on Albert Nile to target Angara, Ngassia and Barbus, is definitely destructive to their fisheries and should be checked forthwith. In addition, there is an emerging fishing method locally referred to as “Salsio or Luzira” whereby fishers stay on the lake from 3 days up to 2 weeks without returning to the landing site. They carry with them food and salt for processing the catches on the lake, and in the case of Albert Nile on make shift shelters on islands and in the game park. They normally use gillnets of 3-31⁄2 inch mesh size and caught mainly Nile perch & Bagrus (Pethi & Munama). On return they land several tons of fish. Most of these Catches are not captured in the estimates presented in our analyses since we target daily fishing boats. The possible impacts of this fishing method should be studied and appropriate action recommended.
Prospects for Aquaculture Development in Africa: A review of past performance to assess future potential
(Center for Development Research, University of Bonn, 2022-01-11) Etienne Hinrichsen; Dr. John K. Walakira; Ms. Sandra Langi; Professor Nabil Ahmad Ibrahim; Dr. Victoria Tarus; Mr. Olanrewaju Badmus; Dr. Heike Baumüller
African aquaculture production has gradually increased over the years, but progress is still slow. Given large variations between African countries with regard to the availability of water, the macro-economic context, access to capture fisheries resources and other factors, the performance of African countries in aquaculture cannot be considered only by absolute production levels or contribution to GDP. Additional indicators must be considered that also take into account the role of aquaculture as a source of food supply as well as other macro-economic variables, such as population size and natural resource endowment. To this end, relevant data were collected for 54 African countries covering a range of indicators, drawing on existing data collections of the World Bank and the Food and Agriculture Organization of the United Nations (FAO). The need for development of the sector and its potentials are identified by assessing African countries’ performance with regard to the role of aquaculture as a source of food supply, absolute and per capita production volumes and values (including changes over time), and the economic importance of the sector. The contribution of aquaculture to national fish supply is highest in Egypt. Lesotho features second in this indicator, but much of the production is targeted at the export market as confirmed by the low level of per capita fish supply. The greatest gap between per capita fish supply and average African fish supply was recorded for Ethiopia (followed by Guinea-Bissau and Sudan). Egypt also leads African aquaculture in terms of absolute production volumes and value (followed by Nigeria). In 2018, Egypt’s production was more than twice the total production of all the remaining African countries put together. In terms of production growth rates over the past decade, however, other countries stand out, including Rwanda, Burundi, Lesotho and Benin, albeit starting from a low base. Lesotho, South Africa and Mauritius lead in the value of production per tonne due to the cultivation of a number of high-value species for export. In terms of the economic importance of the aquaculture sector, its contribution to GDP is highest in Egypt, followed somewhat surprisingly by Lesotho, a country in which there was no aquaculture a mere two decades ago and where today the sector is a significant earner of foreign currency. Egypt also leads with regard to output relative to available renewable water resources (followed by Uganda). The study outlines a number of policy and investment priorities to support the growth of a sustainable, climate-resilient and equitable aquaculture sector in Africa as an integral part of food systems. Particular attention should be paid to engaging and building the capacities of small-scale actors in this sector to contribute to local food security, employment and income generation.
Participatory Processing Diagnosis of Fried Sweetpotato in Nigeria & Ghana
(RTBfoods, 2022-01-12) Reuben SSALI; Ted CAREY; Simon IMORO; Jan LOW; Eric Kuuna DERY; Abena BOAKYE; Rachel M. OMODAMIRO; Hauwa Ladi YUSUF; Eunice ETWIRE; Abigail O. IYILADE; Souleimane ADEKAMBI; Abdullahi ALI; Muhammad HALIRU; Prince Maxwell ETWIRE; Edgar TINYIRO; Alexandre BOUNIOL
A participatory processing diagnosis on fried sweetpotato was conducted with expert fryers to better understand desirable and non-desirable quality characteristics from their perspective. The study encompassed 20 expert fryers across 8 communities in Nigeria (Kano and Kwara States) and Ghana (Bawku, Upper East Region). In both countries, the desirable characteristics of raw sweetpotato for use in the frying operation included; smooth skin, regular shape, big root size, no holes, no off-odours and firmness. The main unit operations involved in preparation were five namely; peeling, slicing, washing, salting and deep frying. Deep frying was the most important unit operation determining the quality of fried sweetpotato product (involved pre-heating vegetable oil 120-185°C). During processing important attributes included; hard when slicing, non-sticky and non-slippery in the hands, uniform colour of slices, non or slight surface moisture and no off-odours. The fried sweetpotato desirable traits were; colour (uniform light brown or yellow/golden, orange with a brown tint), dry/filling/satisfying, hard/strong -at first bite, crispy, not soggy, not oily, and slight-moderately sugary. Preference of the varieties from most to least preferred by processors in Ghana was; Obare, Purupuru, Kuffour and Amuskwera with weighted scores of 32, 21, 16 and 11 respectively. In Nigeria, processors in Kwara State liked Alausa (32) most followed by Pakurumo (21), Tomude (18), Aragbe (12), Mother’s Delight (9) and Elege (6) while for those in Kano state it was; Dan Izala (36), Dan China (24), Dan Bakalori (18), Dan Madagali (14), Dan Barmawa (8), Dan Silver (6) and Mother’s Delight (6).
Technical Report on the Environmental Monitoring of the Cage Area at the Source of the Nile (SON) Fish Farm for Quarter 1: January- March 2011
(National Agricultural Research Organisation, 2011-04-10) Dr. L.M. Ndawula (SRO); Mr.S.B.Wandera(SRO); Mr. H. Ocaya (SLT); Mr.W.PabireGandhi(LT); Ms.J.Naluwairo(LT); Mr.G.Magezi(LT); Mr.V.Kiggundu(SLT); Mr.M.Olokotum(RA)

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