ALBERT

Description: National Fisheries Resources Research Institute (NaFIRRI) undertakes quarterly monitoring of the water environment at Source of the Nile (SON) fish farm. The activity which is through a collaborative arrangement between SON fish farm and NaFIRRI aims at assessing possible changes in the water environment at SON cage area. The fish rearing activity at SON fish farm involves keeping fish in cages often under high stocking densities and feeding them on artificial feeds that are not the natural food eaten by wild fish. Cages being open systems means that all wastes such as faeces, uneaten feed and fish excretes such as ammonia are shed into the water column (Fernandes et al., 2001). The consequence is increased nutrient input which may result into high algal growth (bloom). Although this may mean more food available to primary consumers such as zooplankton, blooms caused by blue-green algae may be harmful as certain species are associated with production of toxins. In addition, the degradation of excessive phytoplankton biomass can lead to anoxic conditions in sediments underlying the cages thus changing the abundance and composition of the resident fauna. Napoleon Gulf being a shallow bay at the exit of River Nile from Lake Victoria harbours a wide variety of wild fish species that are cherished by riparian human populations. The wild fishes living close to cages are bound to be affected by activities associated with this method of fish farming. Cage farming is likely to affect the presence, abundance, diet and residence time of organisms in given vicinity (Carss, 1990; Dempster et al., 2002). Floating structures including cages may act as Fish Attracting Devices (FADs) and most pelagic fishes are known to be strongly attracted to floating objects (Freon and Dagorn, 2000; Castro et al., 2002). Wild fish could be attracted to these sites by for example plenty of food available to the cultured fishes (Bjordal & Skar, 1992). In the process, other ecological interactions between cultured and wild fish may be possible. Wild fish may also be instrumental in cleaning the environment close to the cages through eating any excess uneaten food left by cultured fishes. Caged fish under crowded conditions is susceptible to waterborne diseases and could infect wild fish or vice versa. While diseases breaking out among cultured fishes may be controlled through treatment, the wild fishes cannot undergo treatment and may thus spread diseases to other fishes, hence affecting yields from capture fishery. Furthermore, escape of cultured fish may cause genetic dilution hence decreasing genetic diversity of fish. These and other possible impacts of cages on the water environment may consequently result into conflicts 2 with other resource users especially due to deteriorating water quality and effect on wild fishes, consequently affecting the cage aquaculture industry. Therefore, the following were established as key parameters to be monitored: water temperature, dissolved oxygen, pH, conductivity, water transparency, total suspended solids, nutrient status, algae, zooplankton, benthic macro invertebrates and fish communities. The present report presents field observations made at the two cage sites of Source of the Nile fish farm including upstream, downstream and reference points, for the second quarter (April to June) undertaken in June 2017. The report provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities on the water environment and the different aquatic biota in and around the fish cage site.

Description: The monitoring of water quality and biotic communities at Source of the Nile (SON) fish farm area, for quarter 4 (October – December) was undertaken in December 2017. The activity aimed at assessing possible changes in the water environment at SON cage area. The following parameters were assessed: water physico-chemicals and nutrients, algae, zooplankton, benthic macro invertebrates, and fish communities. Total depth was above 5.0 m (range: 5.63 – 9.74 m) at all sampled points and decreased towards the downstream of cages. Water transparency ranged from 1.26 – 1.48 in the cage area and 1.08 to 1.34 m away from the cages. Within the cage area, Dissolved Oxygen ranged from 5.7 – 6.4 mg/L at the surface, and 5.1 – 6.4 mg/L at the bottom, while in the non-cage areas, the range was 5.5 – 7.5 mg/L at the surface and 2.6 – 7.0 mg/L at the bottom. Temperature ranged from 27.0 – 28.0 o C at the surface and 25.5 – 27.5 o C at the bottom waters for all sites, and were within the optimal range (25 – 32 o C). pH in both surface and bottom waters was above 7.0 (range: 7.5 – 9.2) at all sites. Conductivity within cage area ranged from 100.5 – 102.6 μScm-1 in surface water and 101.8 – 112.1 μScm-1 in bottom water. In the non-cage areas conductivity ranged from 11.0 – 104.4 μScm-1 in surface water and 100.2 – 110.0 μScm-1 at the bottom. Ammonium nitrogen concentration during December was less than 0.02 mg/L at all sites (0.007 – 0.018 mg/L within the cage sites, and 0.012 – 0.019 mg/L in the non-cage sites). Nitrite nitrogen ranged from 0.002 – 0.169 mg/L in the cage area, and 0.003 – 0.057 mg/L in the non-cage areas. Similar to previous records of June and September 2017, nitrate nitrogen concentration generally increased towards the downstream site, being lowest at RPT (0.041 mg/L) and highest at DSC (0.204 mg/L). Soluble reactive phosphorus was less than 0.005 mg/L at all sites, and varied within narrow margin (range: 0.003 – 0.0048 mg/L in cage sites, and 0.0032 – 0.0047 mg/L in non-cage sites). The TP concentration ranged from 0.085 – 0.107 mg/L in the cages, and 0.090 – 0.118 mg/L in the non-cage sites and was higher than recorded in September (0.038 – 0.044 mg/L in the cages and 0.04 to 0.109 mg/L away from cages). Total nitrogen concentration was in the range of 0.138 – 0.553 mg/L within cage area and 0.421 – 0.513 mg/L in non-cage areas. The concentration of TSS ranged from 0.76 – 4.33 mg/L in the cage area and 0.57 – 2.76 mg/L in the non-cage areas. The phytoplankton community was composed of blue-green algae, green algae and diatoms, dominated by blue-green algae. The abundance of algae was higher in the non-cage areas (mean:7.20 ± 2.14 mm3L-1, Range: 5.15 – 10.20 mm3L-1) than recorded in the cage areas (mean: 6.0 ± 0.71 mm3L-1, Range: 5.30 – 6.98 mm3L-1), similar to observations of September 2017 (〈 5 mm3L1 within the cages and 〉5.6 mm3L-1 in the non-cage sites). At all sampled points, blue-green algae contributed 〉70% of total abundance. Total zooplankton abundance ranged from 982,213 – 1,310,830 ind.m-2 in the non-cage sites, and 740,601 – 1,503,130 ind.m-2 in the cage areas. Similar to observations of September 2017, the upper cage site (WIC3 and WIC4) presented lower zooplankton abundance (mean: 788,954 ± 68,381 ind.m-2) when compared to the lower cage site with mean abundance of 1,128,232 ± 530,186 ind.m-2. Like in the previous sampling periods, copepods were the numerically dominant group (92.69 – 97.22 % of total zooplankton abundance) at all sampled points, with no major differences between cage and non-cage areas. The high abundance of copepods was attributed to the abundance of the juvenile stages (copepodites and Nauplius larvae) which contributed 83.72 – 92.78% of the total zooplankton abundance and this was mainly due to the Nauplius larvae (66.4 – 83.2 %). Cladocera relative abundance ranged from 0.32 – 3.98% while that of rotifers ranged from 1.55 – 3.74%. The macro-benthic community comprised molluscs, annelids and arthropods. Taxa richness ranged from 5 – 11 taxa in the cage area, and 7 – 9 taxa in the non-cage areas. The abundance of benthic invertebrates within the cage area ranged from 1,134 – 2,416 ind.m-2 and this was higher than previously recorded in September (294 – 1,415 ind.m-2). In the non-cage sites abundance was in the range of 420 – 3,992 ind.m-2. Oligochaete annelids which are reported to be very tolerant to pollution contributed 0 - 28 % of the abundance of benthos at cage sites and 3 - 20% at the non-cage sites. Diptera made the greatest contribution at almost all sites, with the percent abundance being higher in non-cage sites (40 – 86%) than what was recorded in the cage sites (37 – 82%). Chironomus spp. and Chaoborus sp. were the main contributors to the observed Diptera abundance at all sites. Six fish species, including haplochromines (Nkejje) as a single species group, were recorded in the vicinity of the cages during December 2017. Five fish species were recorded from upstream the cage site, four species from within cage area, and two species from downstream the cages. Overall mean catch rates were 1.8 fish/net/night and 148.6g/net/night compared to 1.7 fish/net/night and 175.4g/net/night recorded in September 2017. By weight, catch rates in December 2017 were highest upstream the cage site (312.1g/net/night) and also by numbers (3.1 fish/net/night). Four species of haplochromines were recorded in the vicinity of the cages during the survey of December 2017 compared to six species recorded in September 2017. The overall catch rate for the haplochromines, in December 2017 was 1.7fish/net/night and 27.5g/net/night compared to 3.4 fish/net/night and 62.3g/net/night recorded in the previous survey of September 2017. Among the fish species examined during December 2017 survey, most of the haplochromine cichlids (88.9%) were mature but only 50% breeding. Only one specimen of L. niloticus was mature and breeding. All S. afrofischeri and S. victoriae specimens examined were mature and in breeding condition while M. kannume was immature. The diet of fishes encountered comprised mostly of fish and insects, which are known natural foods of the fish species. Infection by fish parasites during the survey of December 2017 was not noticed in any fish recorded from the experimental gillnets. The overall observation on concentrations of nutrients, levels of physico-chemical variables, and biotic communities indicated minimal impact of cages on water quality. The farm should therefore continue adhering to the best environmentally sustainable aquaculture practices, especially continuing with fallowing or rotation of cages to allow resident organisms maintain their natural population densities, distribution and community structure in the area; reducing excess uneaten feed and other suspended materials which would impact on nutrient status and biota; as well as wise use of any chemicals in the area.

Description: Kariba weed (Salvinia molesta) is an invasive alien waterweedthat was first recorded in Uganda in sheltered bays of LakeKyoga in June 2013. This waterweed has become a commonfeature on Lake Kyoga and its associated rivers, streams andswamps, and has spread to other lakes notably Kwania and Albert in addition to Lake Kimira in Bugiri district.

Description: Fisheries activities are the main source of livelihood for the communities that live at Lake Edward fish landing sites. The landing sites include: Kazinga, Katwe, Kayanja, Kishenyi Rwenshama and Katunguru and are located within Queen Elizabeth Conservation Area (QECA).In spite of being the main source of livelihood, 74% of therespondents in a 2013 survey reported that catches forthe main targeted fish species namely: Bagrus docmak(Semutundu), Oreochromis niloticus (Tilapia) and Protopterusaethiopicus (Mamba) were declining due to overfishingand catching of immature fish by the rapidly increasingpopulation. Lake Edward Frame surveys had shown that thenumber of fishing crafts increased from 302 in 2008 to 330 in 2011, while the number of fishers increased from 355 to 600 during the same period. Between 2008 and 2010, catch perboat, for Bagrus docmak (Semutundu) declined from 5.25kg to 4.04 kg and for Protopterus aethiopicus (Mamba) from2.63 kg to 1.03kg.It has been suggested that reducing pressure on the lakeshould be handled using different approaches, one of whichis introduction of programs for enhancing livelihood optionswhich do not conflict with conservation of Queen ElizabethConservation Area (QECA). The main goal of this study wastherefore to identify, prioritize and pilot livelihood options at selected landing sites of Lakes Edward and George.

Description: The National Fisheries Resources Research Institute (NaFIRRI), the Directorate of Fisheries Resources (DiFR), the Local Government fisheries staff and those from the Beach Management Units (BMUs) of the riparian districts to Lake Victoria regularly and jointly conduct Frame and Catch Assessment Surveys. The information obtained is used to guide fisheries management and development. We reveal the trends in the commercial fish catch landings and fishing effort on the Uganda side of Lake Victoria, over a 15 year period (2000-2015) and provide the underlying factors to the observed changes. The contribution of the high value large size species (Nile perch and Tilapia) to the commercial catch of Lake Victoria has significantly reduced while that of the low value small size species, Mukene has increased over a ten year (2005-2015)period. The information is intended to update and sensitize the key stakeholders on the status of the Lake Victoria fisheries. In addition, the information provided is expected to guide policy formulation and management planning by the fisheries managers at all levels including the BMUs and Landing Site Management Committees (LSMCs), the Local government fisheries staff and the Directorate of Fisheries Resources. The information is anticipated to create awareness among the lakeside fisher communities to reverse the current trend in fish declines.

Description: Issue 1, Vol. I (Series name not specified)

Description: As interest increases in fish production, fish farming is on the rise as more fish is produced in ponds, cages and tanks. However not all fish can be sold out and consumed at the same time, in addition to this, different consumers show different preference. Some individua Is tend to prefer smoked fish to fresh and fried fish. Apart from satisfying the different consumer preferences, fish smoking is important because it in creases the self life of fish, there by reducing post harvest losses. It also adds value to the fish and in this way the farmer can fetch more money from farmed products. Although the technology has been around for several years amongst the fishing communities, it is not well known amongst fish farmers. There is need to bring fish fanners on board to know how to construct the smoking kiln through the stapes out lined below.

Description: An overview of the biology and ecology of some of the constantly less important commercial species is given below. These included Bagrus docmac, Clarias gariepinus, Protopterus aethiopicus, Labeo victorianus, Barbus spp, Mormyrids, Synodontis spp, and Schilbe intermedius. The stocks of most of these species declined due to over-exploitation and introduction of non-native fishes especially Nile perch. A few of these taxa still survive in the main lake and others in satellite lakes. The current status of these species in the Victoria lake basin is not known but the available information provided some information on some habitat and other requirements of some of these originally important species of the Victoria lake basin.

Description: The number and size composition of gillnets, fishing grounds and thequantity and composition offish catches were related to the size of fishing boat. Theoverall number of gillnets per boat increased from 20.9 ± 2.3 nets in 5-6 m long boatsto 88.6 ± 11.8 nets in 11-12 m long boats. The proportion of large mesh sizes, 〉127mm, also increased from 40.4% in 5-6 m long boats to 100% in boats 〉10 m long. Themajority of large boats, 2:8.0 m long, fished in offshore waters targeting Nile perch,Lates niloticus (L.). Boats 〈8.0 m long fished inshore principally for Nile tilapia,Oreochromis niloticus (L.), although Nile perch was also a major component ofthecatch. Nile tilapia and other fish contributed 31.0-59.9% ofthe catch by weight. Meancatch rates increased from 12.6 ± 1.9 kg in 5-6 m long boats to 78.2 ± 16.4 kg in 1112m long boats. Most Nile perch landed from boats 〈8.0 m long were 〈50 cm TL,smaller than the legal minimum harvest size, whereas 〈17% of Nile perch landed fromlarger boats were 〈50 cm TL. Fish catch is related to the size of boat and this shouldbe considered when formulating management guidelines of the lake's fishery.Promotion of large fishing boats 2:8.0 m and restrictions on the number of boats and/or mesh size of gillnets of smaller boats could increase ecological and socio-economic benefits.

Description: Kyoga basin lakes are a very important natural resource for' the communitieswithin the lake basin and beyond. Fisheries of the Kyoga basin lakes enablemillions of poor fishers, processors and traders to diversify their livelihoodstrategies on the basin of income while at the same time supplying vast numbersof poor consumers with essential nutrition. Fish is particularly important for thepoor as it is often the most readily available and affordable source of protein andother micronutrients crucial to a healthy diet. The lakes also generate substantialrevenue to the local governments within their catchment's area. Thus thefisheries of Kyoga basin lakes are a key instrument in poverty eradication and ."food security

Description: The massive water hyacinth mats that covered water bodies in the 1990s had serious social and economic impacts. They affected fishing, transportation, water quality and health of fishing communities as well as production of goods and services of lake-based institutions (commercial establishments). At peak infestations, the communities and institutions were aware of and participated readily in control effort. However, after the major collapse of hyacinth in 1998, some of them relaxed in their control efforts. The status of knowledge, perception, impacts, preparedness and role of the lakeside communities and institutions to control the weed has, therefore, been monitored since the major resurgence of the weed to find out if the lakeside communities and institutions still perceive water hyacinth as a problem and the extent to which they are prepared to sustain control

Description: FIRRI Technical Document, Draft 2, April 2002