ALBERT

Beschreibung: The number and size composition of gillnets, fishing grounds, and the quantity and composition of fish catches were related to the size of fishing boat. The overall number of gillnets per boat increased from 20.9 + or - 2.3 nets in 5-6 m long boats to 88.6 + or - 11.8 nets in 11-12 m long boats. The proportion of large mesh sizes, + or more than 127 mm, also increased from 40% in 5-6 m long boats to 100% in boats longer than 10 m. Fish catches are related to the size of boat and this should be considered when formulating management guidelines of the lake's fishery. Promotion of large fishing boats 8 m or longer and restriction on the number and/or mesh size of gillnets of smaller boats could increase ecological and socio-economic benefits.

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/07

Beschreibung: Bottom trawl surveys were conducted in Kenyan waters of Lake Victoria during the period September 1997 and March 1999. The means of fish biomass for the two most important species: Lates niloticus (L.) and Oreochromis niloticus (L.) were estimated at 61.5 kg ha and 4.5 kg ha respectively. There were few L. niloticus greater than 80 cm TL and O. niloticus greater than 50 cm TL, though these species attain maximum sizes of 205 cm and 65 cm respectively. Oreochromis niloticus was mostly found shallower than 5 m though some specimens were encountered deeper than 10 m, suggesting that the species has extended its ecological range. Very low catches were obtained from areas under water hyacinth cover. Water in such areas was turbid with oxygen levels below the critical 3.0 mg L.

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/07

Beschreibung: The reproduction of Nile tilapia, Oreochromis niloticus (L.), in the Nyanza Gulf of Lake Victoria was studied from June 1998 to May 1999. Length at maturity ranged from 28-30 cm TL for females and from 32-34 cm TL for males. Males were more abundant in all length classes longer than 36 cm TL. Relative condition factor was above unity, except in August, October and May for males, and October for females. Gonadosomatic index (GSI) was low during the post spawning period (July to October) and high during the protracted breeding period (December-June).

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/07

Beschreibung: In a tagging experiment carried out in the Kenyan waters of Lake Victoria, an annual growth increment of 29 cm yr was obtained for Lates niloticus (L.). Growth parameters obtained using the von Bertalanffy model on the growth curve fitted by eye were L (inf.) = 122 cm yr and k = 0.26 yr. Data for other species tagged were inadequate to obtain meaningful results.

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/07

Beschreibung: The Lake Victoria fish fauna was dominated by cichlids before the establishment of the exotic species Oreochromis niloticus (L.) and Latus niloticus (L.). With the alterations in the ecology of Lake Victoria, changes may be expected to occur in the population dynamics of the fish species. In two zones of Lake Victoria, the size structure, distribution and abundance, condition factors, length-weight relationship and sex ratios of O. niloticus were determined. Larger fish were found in zone II than in zone III, where very few larger fish were recorded. More O. niloticus were caught in zone III, especially in Itome Bay, than in zone II but catch by weight was greater in zone II. More males than females were encountered in both zones. Oreochromis niloticus had similar condition factors in both zones.

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/07

Beschreibung: Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm requested for technical assistance of NaFIRRI to undertake regular environment monitoring of the cage site as is mandatory under the NEMA conditions. Thus, NAFIRRI undertakes quarterly environment surveys in the cage area covering selected physical-chemical factors i.e. water column depth, water transparency, water column temperature, dissolved oxygen, pH and conductivity; nutrient status, algal and invertebrate communities (zooplankton and macro-benthos) as well as fish community. The first environmental survey was undertaken in February 2011. Results/observations made during the second quarter (April-June 2011) field survey are presented in this technical report along with 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 cages including natural fish communities.

Beschreibung: Tullow Oil plc is to launch an onshore Early Production System (EPS) of oil drilling rated at 4,000 barrels of oil per day by 2009. The location of the EPS is in the Kaiso-Tonya area of Block 2 Oil Exploration Zone along Lake Albert within the Albertine graben. Tullow Oil plc contracted Environmental Resources Management (ERM) Southern Africa (Pty) Ltd in conjunction with Environmental Assessment Consult Limited (EACL) to undertake an Environmental Impact Assessment (EIA) for pre-construction and operation of the proposed EPS. ERM in association with EACL requested National Fisheries Resources Research Institute (NaFIRRI) to conduct a baseline survey of water quality and invertebrates in River Hohwa. This study was requested as part of an earlier baseline survey conducted at the Kaiso-Ngassa spit oil exploration area in Block 2. It was conducted at five selected sites (Fig. 1 & Table 1) within the Hohwa River basin in the Kaiso-Tonya Exploration Area 2. The study was pertinent because the targeted oil wells for EPS are upstream this river which drains the Kaiso-Ngassa valley into Ngassa lagoon.

Beschreibung: Environmental Assessment Consult Limited (EACL)

Beschreibung: Following the commencement of construction works of a 250 MW hydropower plant at Dumbbell Island in the Upper Victoria Nile in September 2007, BEL requested NaFIRRI to conduct continuous monitoring of fish catches at two transects i.e. the immediate upstream transect of the project site (Kalange-Makwanzi) and the immediate downstream .transect (Buyala-Kikubamutwe). The routine monitoring surveys were designed to be conducted twice a week at each of the tWo transects. It was anticipated that major immediate impacts were to occur during construction, and these needed to be known by BEL as part of a mitigation strategy. For example, the construction of it cofferdam could be accompanied by rapid changes in water quality and quantity downstream of the construction. These changes in turn could affect the fish catch and would probably be missed by the quarterly monitoring already in place. Therefore, a major cbjective of the more regular and rapid monitoring was to discern immediate impacts of construction activities by focusing on selected water quality parameters (total suspended solids, water conductivity, temperature, dissolved oxygen and pH) and fish catch characteristics (total catch, catch rates and value of the catch)

Beschreibung: Prepared for Bujagali Energy Limited (BEL)

Beschreibung: Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern LakeVictoria. The proprietors of the farm have a collaborative arrangement with NaFIRRI to undertake quarterly environment monitoring of the cage site as is mandatory under the NEMA conditions. The monitoring surveys cover selected physical-chemical factors i.e. water column depth, water transparency, water column temperature, dissolved oxygen, pH and conductivity; nutrient status, algal and invertebrate communities (micro-invertebrates/zooplankton and macroinvertebrates/macro-benthos) as well as fish community. The second quarter survey for the calendar year 2015, which is the subject of this report, was undertaken in June 2015.Results/observations made are presented in this technical report along with a scientificinterpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aquatic biota.

Beschreibung: Source of the Nile (SON) Cage Fish farm is located at Bugungu in Napoleon Gulf, northern Lake Victoria, near the headwaters of the River Nile. NaFIRRI has, through a Public-Private collaborative partnership with SON management, undertaken quarterly monitoring of the cage fish farm since 2011. The objective of the environment monitoring is to track possible environment and biological changes as a result of fish cage operations in the area. The agreed study areas cover selected physical-chemical parameters i.e. water depth, transparency, column temperature, dissolved oxygen, pH and conductivity; nutrient status; and biological parameters i.e. algae, zooplankton, macro-benthos and fish communities. The fourth quarter survey, which is the subject of this report was undertaken during December 2015. Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aquatic biota.The present report presents field observations made for the fourth quarter survey undertaken in December 2015 and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota in and around the fish cage site.

Beschreibung: This monitoring survey No. 11 undertaken between 4th and 9th September 2012 is the second one to be conducted after completion of construction of Bujagali HydropowerDam. Two pre-construction baseline surveys in April 2000 and April 2006 were conducted and during construction phase, eight monitoring surveys (September 2007,April 2008, April 2009, October 2009, April 2010, September 2010, April 2011, September 2011) were conducted.

Beschreibung: Carried out on behalf of Bujagali Energy Limited (BEL)

Beschreibung: The purpose of inlake herbicide trials was to assesson the aquatic environment and resources, of in-lakeof weeder 64 (2,4-0 amine) and Rodio (Glyphosate)water hyacinth the effects application to control water hyacinth. The experiments reported here specifically studied the effects of the herbicides on the diversity and abundance of aquatic macrofauna associated with the water weed. Results from this and similar experiments which assessed herbicide efficacy on water hyacinth; dissipation in water, impact on water quality, algal biomass and on diversity and abundance of zooplankton and macrofauna were all to be evaluated as input into the environmental impact assessment exercise required to facilitate decisions on the use of herbicides to control water hyacinth in Uganda.

Beschreibung: The National Fisheries Resources Research Institute (NaFIRRI) on behalf of OPEP Consult Ltd undertook a baseline survey of the transition zone (basically along the shoreline) and near shore habitats of the Uganda apart of Lake Edward and Kazinga channel during December 2007 to January 2008. A major objective of the baseline survey was to generate baseline information on the aquatic ecosystem features related to the fisheries and socio-economics of the fish catch including issues raised by residents in the fish landing sites. Therefore, the baseline survey captured information on water quality, the aquatic invertebrate fauna, aspects of fish biology and ecology, the fish catch including facilities at fish landings, value in the catch and related fisheries socio-economic issues perceived by residents in the settled areas along the shores.

Beschreibung: Relationships between nutrient concentrations and water hyacinth biomass and composition have been studied in the shallow inshore bays of lakes Victoria, Kyoga and Albert. Additional information was obtained from Victoria Nile, Albert Nile and Kagera River. In this section, seasonal changes in nutrients and oxygen concentrations are used to explain changes in water hyacinth composition, biomass and distribution in Lake Victoria. Lake Victoria is of particular interest because it experienced strong hyacinth infestations in 1995, a sink in 1998 and resurgence in 2001. The lake has also been extensively sampled and provides time series data in nutrient, oxygen, mixing and thermal stratification which provide an opportunity to relate water hyacinth distribution and biomass to environmental factors. The possible origins and impacts of nutrient loads into Lake Victoria are also discussed in relation to water hyacinth proliferation and distribution especially in relation to known 'hot-spots'.

Beschreibung: On title page: Draft 2

Beschreibung: The massive water hyacinth mats that covered water bodies in the 1990s hadserious social and economic impacts. They affected fishing, transportation,water quality and health of fishing communities as well as production of goodsand services of lake-based institutions (commercial establishments). At peakinfestations, the communities and institutions were aware of and participatedreadily 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 andinstitutions to control the weed has, therefore, been monitored since the majorresurgence of the weed to find out if the lakeside communities and institutionsstill perceive water hyacinth as a problem and the extent to which they areprepared to sustain control.

Beschreibung: On title page: Draft 2

Beschreibung: Biological control was foreseen as the long-term strategy for controlling water hyacinth in Uganda. Two species of weevils, Neochetina eichhorniae and Neochetina bruchi were imported into Uganda from Benin (West Africa) in 1993. A total of 600 weevils of each species were imported. The weevils were tested for specificity using key agricultural crops including maize, beans and bananas and were found to be water-hyacinth specific for their food and reproduction.

Beschreibung: On title page: Draft 2

Beschreibung: The strategy to control the noxious water hyacinth requires reliable data base on the magnitude of the weed problem. This report which presents up to date (1997) information on distribution, coverage and movement of the weed in Uganda is intended to provide this basis as suppliment to other inputs for control planning. The report is the first in a series being prepared by FIRI from results the "Water hyacinth. research project" whose major goal is to supply information needed to define and focus the scope of the control process for water hyacinth in view of the fact that the weed is to remain a permanent feature of the aquatic landscape of Uganda.Water hyacinth is firmly established in lakes Victoria, Kyoga Albert and along the River Nile, distributed in two distinct forms namely as stationary fringes the shoreline and as mobile mats and large "fields" usually found in sheltered bays.

Beschreibung: Over the years, degradation of the lakeshore resources has been going on due to human induced activities. Human activities notably house construction, fish smoking, boat construction and cooking at the landings impact the tree and forest cover along the lakeshore and Islands. The survey was conducted in ten districts surrounding Lake Victoria and the landings sampled were selected with the help of the District Fisheries Officers. Data was obtained from selected fishermen and Key informants at these landing sites. The study examined the extent of knowledge on importance, utilization, threats and conservation of trees/forests at the landings. Results showed that the fishers (98%) were aware of the benefits derived fromthe trees/forests. According to the respondents, the most commonly used tree species for boat construction were Mvule (40%), Mkibu (20%), Musizi (17%) and Mpewere (11 %). This was mainly because these trees were durable. For houseconstruction, Nsambya (25%), Musizi (24%) and other materials (12%) were the most commonly used. For other activities like fish smoking and cooking at the landing, the Fisherfolk used any type of tree species readily available at the landings.As regards the status of the trees at the landings, most of the respondents (72%) J agreed that due to some fishery related activities some tree species had reduced more than others in the vicinity of most landings. Most respondents said that the, most reduced tree species around the landings were Mvule (36%) and Musizi (22%). Among the fishery related activities that had a significant impact on the trees/forests, construction of houses (44%) and boats (22%) emerged uppermost. Other activities such as fish smoking (14%) and cooking (12%) had the least impact on trees/forests. Generally, there was extensive reduction of trees at the landings. Therefore there was need to regulate cutting of trees and to have specific programmes targeting afforestation at and around fish landings.

Beschreibung: The results reported on were from a monitoring survey No. 9 undertaken between 9th and 12th September 2011 during construction period of the Bujagali Hydropower Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far, during construction phase of the project, eight monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009, October 2009, April 2010, September 2010, April 2011 and the present one, in September 2011. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects:water quality determinants biology and ecology of fishes and food webs fish stock and fish catch including economic aspects of catch and sanitation/vector studies (bilharzias and river blindness)in addition to the above mentioned studies, a soil pH survey was undertaken on 15th October 2011 in the area behind the reservoir whose filling started a week earlier. The findings of pH status in the catchment of the dam are also contained in this report.

Beschreibung: The mobile water hyacinth, which was produced in growth zones, especially Murchison bay, was mainly exported to three sheltered storage bays (Thruston, Hannington and Waiya). Between 1996 and May 1998, the mobile form of water hyacinth occupied about 800 ha in Thruston bay, 750 ha in Hannington bay and 140 ha in Waiya bay). Biological control weevils and other factors, including localised nutrient depletion, weakened the weed that was confined to the bays and it sunk around October 1998. The settling to the bottom of such huge quantities of organic matter its subsequent decomposition and the debris from this mass was likely to have environmental impacts on biotic communities (e.g. fish and invertebrate), physico-chemical conditions (water quality), and on socio-economic activities (e.g. at fish landings, water abstraction, and hydro-power generation points). Sunken water hyacinth debris could also affect nutrient levels in the water column and lead to reduction in the content of dissolved oxygen. The changes in nutrient dynamics and oxygen levels could affect algal productivity, invertebrate composition and fish communities. Socio-economic impacts of dead sunken weed were expected from debris deposited along the shoreline especially at fish landings, water abstraction and hydropower generation points. Therefore, environmental impact assessment studies were carried out between 1998 and 2002 in selected representative zones of Lake Victoria to identify the effects of the sunken water hyacinth biomass.

Beschreibung: On title page: Draft 2

Beschreibung: Proliferation of invasive aquatic weeds has developed into a major ecological and socio economic issue formany regions of the world. As a consequence, inference on where to target control and other managementefforts is critical in the management of aquatic weeds (Ibáñez et al., 2009). Notwithstanding, aquatic systemsin Uganda in general and in the basins of Lakes Victoria and Kyoga in particular, have fallen victims to aquaticweeds invasion and subsequent infestation. If these aquatic weeds infestations are to be minimized and theirimpacts mitigated, management decisions ought to be based on up-to-date data and information in relation tolocation of infestation hotspots. Aquatic systems in the basins of the two production systems are importantsources of livelihoods especially from fish production and trade yet they are prone to infestation by aquaticweeds. Thus, the invasion and subsequent infestation of aquatic ecosystems by aquatic weeds pose a majorconservation threat to various aquatic resources (Catford et al., 2011; Kayanja, 2002).This paper examines the extent to which aquatic weeds have infested aquatic ecosystems in the basins ofLakes Victoria and Kyoga. The information is expected to guide management of major aquatic weeds throughrational allocation of the scarce resources by targeting hotspots.

Beschreibung: Reports of hydrilla (Hydrilla verticilata) infestation lakes Bisina and Opeta were verbally communicated by some members of FIRRI who undertook surveys during the LVEMP 1 phase (1997 to 2004) to assess the diversity and stocks of fishes in the Kyoga basin satellite lakes. This issue was taken up by FIRRI and NAARI staff who work on aquatic weeds management to ascertain and quantify the presence of H. verticilata and other aquatic weeds, with the sole aim of finding ways and means of controlling one of the world's worst aquatic weeds, H. verticilata.The survey on Lake Opeta indicated that this weed was rare since only a few small broken pieces were sited at the lake's outflow through an extensive wetland to Lake Bisina. It was therefore concluded that it was not economically viable to allocate resources for further survey of H. verticilata on Lake Opeta. This finding therefore discredited the previous (informal) reports that H. verticilata was well established on Lake Opeta. It should be noted that the reports came from scientists who were not well versed with systematics of aquatic plants.

Beschreibung: Weeds are plants growing in environments where they are undesirable. Aquatic weeds in fresh waters are nuisance or noxious plants growing in association with water in lakes, impoundment, rivers, canals, wetlands, etc. Some waterweeds cause very big financial loss through the socio economic, environmental and ecological impacts they inflict; and through the effort and expense required for their control. Other waterweeds are simply nuisance plants that cause minimal impacts. This paper is intended to introduce aquatic weeds outlining their characteristics, the main socio-economic and environmental impacts associated with them, and the control strategies often applied for their management.

Beschreibung: ACP - EU Fisheries and Biodiversity Project

Beschreibung: The poster explains the effects of aquatic plants to fisheries and how they can be controlled.

Beschreibung: 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.

Beschreibung: Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm requested for technical assistance of NaFIRRI to undertake regular environment monitoring of the cage site as is mandatory under the NEMA conditions. As the SON is a key collaborator/client of the institute, NAFIRRI agreed to undertake the assignment subject to facilitation by the client. The institute agreed to conduct quarterly surveys of key environmental parameters at the site including selected physical-chemical and biological factors, nutrient status, column depth, water transparency and sedimentation. Samples and field measurements were to be taken at 3 sites: within and/or close to the fish cages (WIC), upstream (USC) and downstream (DSC) of the cages. The first environmental monitoring survey was undertaken in February 2011; the second in May 2011 and the third in September 2011. The surveys cover physical-chemical parameters, nutrient status, invertebrate and fish communities. The present report presents field observations made for the fourth quarter survey undertaken in November 2011 and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota at and around the cage site including natural fish communities.

Beschreibung: Giant salvinia (Salvinia molesta) is an introduced invasivewater weed in the tropics and subtropics It is a free floating weed that grows rapidly and forms extensive dense mats over still or slow moving waters.

Beschreibung: Human use of water resow-ces in Uganda has grown and intensified along with population growth and increasing demand to meet the diverse human needs. In the case of Uganda's rivers, the main uses include fisheries,hydropower generation, abstraction for potable water supply, discharge of sewage and navigation. All these uses can disrupt the integrity of the aquatic ecosystem and may affect the survival of the diversity of organisms. In consideration of the need to increase electricity to meet demand, the Bujagali Hydro-power Project (BHPP) and the National Environment Management Authority (NEMA) recognised the importance of safeguards to mitigate impacts of the project. The National Fisheries Resources Research Institute (NaFIRRI) was assigned the role of providing baseline information on the aquatic ecosystem of the Upper Victoria Nile and to follow up the findings with a monitoring framework during construction and post-commissioning phases.

Beschreibung: Policy brief No.3 OF 2012.

Beschreibung: The results reported on were from a monitoring survey No.7 undertaken between 4 th and 7thSeptember 2010 during construction period of the Bujagali Hydropower Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far, during construction phase of the project, six monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009, October 2009, April 2010 and the present one, in September 2010. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects:I. water quality determinants2. biology and ecology of fishes and food webs3. fish stock and fish catch including economic aspects of catch and4. sanitation/vector studies (bilharzias and river blindness)

Beschreibung: The purpose of this present study therefore is to provide and update the AES Nile Power EIA baseline information on the ecology of the river ecosystem prior to the construction of the dam. The study is intended to provide a basis for evaluating the impact of the project on the river environment, the biological resources associated with it and fisheries socia-economics and the vector/sanitation status.This report presents the findings of the first sampling regime which was conducted between the dates of 6th-13th April 2006 and compared with the AESNP Environmental Impact Assessment findings of the second quarter carried out during 5th-14th April 2000.

Beschreibung: Bujagali Hydropower Project (BHPP), Uganda fisheries component

Beschreibung: Report prepared for RJ. Burnside International Limited

Beschreibung: The specific objectives were to:WATER QUALITY1. To measure the water physical variables as indicators of environmental conditions in the upstream and downstream transects of Kalange (1) and Buyala (2), respectively,2. To determine the concentrations of total suspended solids as a major constituent likely to be released into the waters at any time during the construction activities, by comparing the concentrations at the two transects.FISH CATCH1. To follow up trends in fish catch as construction activity progresses, and to precision of the estimate;2. To estimate the prevailing fish catch rates, total fish catches and the total value of the fish catch to the local fishers at the two transects.

Beschreibung: On title page: Environmental and Social Impact Monitoring of the Bujagali Hydropower Project (BHPP), Uganda Fisheries Component

Beschreibung: The aquatic ecosystem of the Upper Victoria Nile is part of a wider complex of water bodies (lakes and rivers) in Uganda that is of immense socioeconomicimportance, especially the fisheries. A source of food, income, energy, irrigation and drinking water, the protection, sustainable use and management of the Upper Victoria Nile water resources are vital to Uganda's economy. The Upper Victoria Nile,due to its abundance of socio-economic benefits,provides a significant contribution to Uganda's economy. The fisheries contribute to the sector as a major source of the export earnings, second to coffee (NEMA,1996), sustain small fishing villages,provide income and generally improve nutrition. Apart from the socio-economic significance of the fisheries,the riverine features of the Upper Victoria Nile, especially its hydropower potential,distinguish this river from the rest of the aquatic ecosystems in the country.

Beschreibung: 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.

Beschreibung: 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.

Beschreibung: This report represents the key output of a training workshop hosted by Lake Victoria Fisheries Research Project (LVFRP) for researchers from each of the riparian countries fisheries research institutes. The workshop aimed to train the researchers in participatory research techniques which they could use to undertake a study of community-based institutions and organizations which could potentially be involved in fisheries co-management. A central focus of the workshop was a study to identify the community-based organizations and institutions, which operated at Kiumba beach, and this study is reported here. Separate reports, which include operated at Kiumba beach and this study is reported here. Separate reports, which include details of the training process and the participatory methods used, are available (Sarch 1995, 2000). The report centers on the information generated from the participatory pilot study conducted by the workshop participants and the community at Kiumba Beach over the course of a week in March 2000. Ranges of participatory research techniques were used and the discussion and diagrams, which resulted from them, form the basis of this report. The workshop participants undertook a preliminary analysis of these findings and this has been synthesized at the end of this report. (PDF contains 55 pages)

Beschreibung: Republic of Kenya

Beschreibung: Republic of Uganda

Beschreibung: United Republic of Tanzania

Beschreibung: European Development Fund (7ACP-RPR-372)

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/00/08. Socio-economic Data Working Group of the Lake Victoria Fisheries Research Project (SEDAWOG)

Beschreibung: Fish samples were collected using seine and trawl nets in Nyanza Gulf, Lake Victoria (Kenya) in order to study the reproductive and gonadal patterns of Oreochromis niloticus; samples were collected from June 1998 to February 1999. The variation in relative condition factor and monthly variation in gonad weight showed spawning took place between June and July. Most ripe fish were recovered between November and February, while a slight drop in GSI for males was noted between November and January. External factors triggering reproductive strategy are now being addressed

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/06

Beschreibung: The management of Lake Victoria is a high priority to the riparian countries that benefit directly from its resources. Management regulations have been formulated and implemented with the aim of maintaining the lake's ecological quality as well as sustaining fisheries exploitation for economic gain. Results indicate, however, that the regulations have not been successful in maintaining the state of the lake's ecosystem nor the fisheries. There has been a continuing decline in fish catches as well as declining biodiversity. Currently, the riparian countries are considering the introduction of a co-management regime as an alternative managerial strategy to address the lake's problems. In this paper it is argued that the failure of the former management regulations was because ownership of the lake was not clearly defined. It is further argued that even if co-management were to be successfully instituted, it will yield very minimal results if the problem of ownership is not properly addressed. This paper explores the ownership status of the lake based on data collected in Tanzania, and examines the relationship between, and significance of, ownership and co-management. The research makes recommendations for how these concepts can contribute to an integrated management of the lake

Beschreibung: European Development Fund (7ACP-RPR-372)

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/00/11

Beschreibung: Fourteen stations were sampled in the Kenyan waters of Lake Victoria in order to assess distribution and abundance of zooplankton. Seven stations were selected in the Nyanza gulf while the rest were in the open waters of the lake. Zooplanktons samples were collected monthly from November 1998 to January 1999, using a 1.5 m long Nansen type plankton net of 243 mu m mesh size and 50 cm diameter. Representative specimens were dissected and identified to species level

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/06. This article was also published in LVFRP/TECH/99/07 as follows: Omondi, R. (1999) The distribution and abundance of Copepoda and Cladocera in the Lake Victoria, Kenya In: Report on Fourth FIDAWOG Workshop held at Kisumu, 16 to 20 August 1999, pp. 127-141.

Beschreibung: An experimental bottom trawl survey was carried out in the Uganda sector of Lake Victoria from November 1997 to December 1998 to estimate the composition, distribution, and abundance of the major fish species. In 12 cruises, 295, thirty-minute hauls were taken in waters from 4-60 m deep. Nile perch, Lates niloticus (L) made up 95% of the catch by weight. Haplochromine cichlids and L. niloticus occurred in all areas sampled while Nile tilapia, Oreochromis niloticus (L.) and other tilapiines were restricted to waters less than 30 m deep. In waters deeper than 40 m, catches were generally near zero. Species diversity and abundance decreased with increasing water depth. In waters less than 30 m deep, the area where the artisanal fishermen operate, the mean catch was 126kg hr super(1)

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/06

Beschreibung: Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm and the National Fisheries Resources Research Institute (NaFIRRI) have an established collaborative arrangement where NaFIRRI provides technical back-stopping to enable quarterly environment monitoring of the cage site; a mandatory requirement of the National Environment Management Authority (NEMA). The agreed studyareas are physical-chemical factors (water depth, water transparency/secchi depth, water temperature, dissolved oxygen, BOO, pH, conductivity), and selected nutrients), algal community (including primary production), aquatic invertebrates (zooplankton and macrobenthos) and the fish community. This report presents field observations made during the third quarter (July-September) field survey undertaken during August 2014; along with scientificinterpretation and discussion of the results in reference to possible impacts of the cage facility to the water environment quality and aquatic biota.

Beschreibung: Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm requested for technical assistance of NaFIRRI to undertake regular environment monitoring of the cage site as is mandatory under the NEMA conditions. NAFIRRI agreed to undertake quarterly environment surveys in the cage area covering selected physical-chemical factors Like water column depth, water transparency, water column temperature, dissolved oxygen, pH and conductivity; nutrient status, algal and invertebrate communities (microinvertebrates/zooplankton and macro-invertebrates/macro-benthos) as well as fish community. The first quarter survey was undertaken in February 2011; the second in May 2011 and the third quarter survey, which is the subject of this report, in September 2011. Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aq-uatic biota, including the natural fish community at and around the cage site.

Beschreibung: The first year-round quarterly surveys were completed for the year 2011. For the year 2012, SON management decided to change the frequency of the surveys from quarterly to biannual and the first such survey, was undertaken in June 2012. The second survey was undertaken in December 2012 and is the subject of this report: Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aquatic biota.SON cage study sites were coded as downstream of cages (DSC), within cages (WIC) and upstream of cages (USC). Physical-chemical parameters (water column temperature, dissolved oxygen, pH, conductivity, were measured in-situ with a pre-calibrated hydrolab at each site. A digital Echo Sounder was used to determine the total water column depth at each site. A black and white Secchi disc was used to determine water column transparency. Coordinate locations were determined with a GPS device.

Beschreibung: Physical control of water hyacinth consists of removing the plants from the water by hand or machines. It is considered over effetive because it involves removing the whole plants from water. The first attempt on physical controlwas in 1992 when weed infestation was causing serious problems to the fishing communities in Lake Kyoga. The fishermen had problems of accessing the lake as huge masses of mobile weed blocked landing sites. Furthermore,the fishers lost their nets, which were swept away by mobile water hyacinth. As a result, an integrated control strategy involving physical control (manual and mechanical removal) was put in place. Through this method, the fishers were able to open up access routes to fishing grounds even though weed mats often reblocked the access routes. In the infested lakes, manual removal offered remedial relief to fish Iandings and other access sites. Sites of strategic importance such as hydro-electric power generation dam, water intake points and docking points which had large masses of water hyacinthrequired heavy machinery and mechanical harvesters were used at these sites.

Beschreibung: On title page: Draft 2

Beschreibung: Three commercially important fish species, Lates niloticus (L.), Rastrineobola argentea (Pellegrin) and Oreochromis niloticus (L.) that are fished by artisanal fishermen of Lake Victoria, Tanzania part, were studied in Kagera, Mwanza and Mara beaches from October 1997 to July 1999. Catches, effort, exploitation and stock structure were investigated. Beaches for sampling were selected based on importance for landing the above named fish species. The number of boats found on beach that day, the number that lay idle and their means of propulsion were recorded. As many boats as possible were sampled for gear type and gear size. The catches were sorted into species and measured. Variation in the species and size composition of landings was observed between regions, between months and between gears used. The implications of the findings to management are discussed.

Beschreibung: Lake Victoria Fisheries Research Project Phase II

Beschreibung: LVFRP/TECH/99/07

Beschreibung: The first environmental survey was undertaken in February 2011. The survey covered physical-chemical parameters (Water depth, water transparency, water column temperature, dissolved oxygen, pH and conductivity), nutrient status, algal and invertebrate communities (algae, micro-invertebrates/zooplankton and macro-invertebrates/macro-benthos) and the fish community. This report presents the field observations made and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota at and around the cage site including natural fish communities.

Beschreibung: The diet of Oreochromis niloticus (L.) is now more diverse than earlier reported. Oreochromis niloticus was considered to be a herbivore feeding mostly on algae and plant material. The diet now consists of insects, fish, algae and plant material. The shift in diet may be due to ecological changes in the lake. Water hyacinth, Eichhornia crassipes (Mart.) Solms, which harbours insects in its root balls, now has extensive coverage of the lake. The native species which preyed on insects (e.g. haplochromines) have largely been eliminated and O. niloticus may be filling niches previously occupied by other species. The change in diet may also be related to food availability and abundance, with the fish feeding on the most easily available food items.

Beschreibung: Njiru, M. (1999) Feeding ecology and population characteristics of Oreochromis niloticus (L.) and trophic interactions in the fish community of Nyanza Gulf, Lake Victoria, Kenya. In: Tweddle, D. and Cowx, I.G. (eds.) Report on third Fisheries Data Working Group (FIDAWOG) workshop held at the Triangle Hotel, Jinja, 29 March to 1 April 1999. Jinja, Fisheries Data Working Group of the Lake Victoria Fisheries Research Project, pp. 68-72. (LVFRP Technical Document,6)

Beschreibung: Published

Beschreibung: The distribution, diversity and abundance of littoral zooplankton, and the relationships between zooplankton and juvenile fishes in the littoral zone (Lates niloticus (L.), Oreochromis niloticus (L.) and Rastrineobola argentea (Pellegrin)) are being studied. Copepoda were tha most abundant zooplankton in most samples followed by Rotifera and Cladocera. Cyclopoid copepods were more abundant than calanoids. Rotifera was the most diverse group with 33 species recorded. Lates niloticus shifted from a diet of zooplankton to other food items, mainly insects, Caridina nilotica (Roux)and fish as they grew. Juvenile O. niloticus shifted from a zooplankton diet to one of insects, phytoplankton and plant material as they grew. Rastrineobola argentea fed mainly on cladocerans though copepods were also consumed. Changes in feeding preferences were observed spatially and temporally.

Beschreibung: Published

Beschreibung: Bottom trawl surveys were conducted in Kenyan waters of Lake Victoria during the period September 1997 and March 1999. The means of fish biomass for the two most important species: Lates niloticus (L.) and Oreochromis niloticus (L.) were estimated at 61.5 kg ha and 4.5 kg ha respectively. There were few L. niloticus greater than 80 cm TL and O. niloticus greater than 50 cm TL, though these species attain maximum sizes of 205 cm and 65 cm respectively. Oreochromis niloticus was mostly found shallower than 5 m though some specimens were encountered deeper than 10 m, suggesting that the species has extended its ecological range. Very low catches were obtained from areas under water hyacinth cover. Water in such areas was turbid with oxygen levels below the critical 3.0 mg L.

Beschreibung: Published