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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.

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Browsing Organisation Reports by Author "Angela Nankabirwa"