The potential of Nakivubo swamp (papyrus wetland) in maintaining water quality of inner Murchison bay - Lake Victoria

Nakivubo swamp (papyrus wetland) is located in the south east of the city of Kampala, Uganda. This swamp has been receiving waste water from Nakivubo channel for more than two decades. This investigation was aimed at monitoring the level of pollutants (nutrients and faecal coliforms) as the waste water filtrates through the swamp and the flow patterns of waste water through the swamp. From this preliminary investigation it was found out that the waste water is not evenly distributed over the swamp. Also high levels of pollutants seem to filtrate through the swamp and enter Inner Murchison Bay - Lake Victoria. Further research is under way to investigate in more detail the capacity of Nakivubo swamp to remove nutrients/pollutants from waste water flowing through it and the dominant mechanisms/processes involved.

Photographic database development of Nigerian fisheries: a complementary source of information documentation

The paper traces the history of the different documentation media used for information dissemination. Such early media are clay tablets, papyrus, and vellum or parchment codex. The invention of printing however revolutionized the information industry, enabling the production of books in multiple copies. Photography came into documentation mainly to preserve rare materials and those that easily deteriorate. This paper reports the efforts of National Institute for Freshwater Fisheries Research (NIFFR) and Kainji Lake Fisheries Promotion Project (KLFPPP), Nigeria, to develop an Object Oriented Database (OOD) using photographs. The photographs are stored in digitized form on commercial computers, using the program ACDSee 32 for classification, description and retrieval. Specifically the paper focuses on photographs in fisheries as visual communication and expression. Presently, the database contains photo documents about the following aspects of Kainji Lake fisheries: fishing gears and crafts, fish preservation methods

Comparative study of hatching rates of African catfish (Clarias gariepinus Burchell 1822) eggs on different substrates

The hatching rates of African catfish (Clarias gariepinus) eggs on four natural substrates: the roots of Nile cabbage (Pistia stratiotes), water hyacinth (Eichhornia crassipes), pond weed (Ceratophyllum dermasum) and green grass leaves (Commelina sp.), and four artificial substrates: sisal mats, nylon mats, papyrus mats and kakaban mats, was assessed. Concrete slabs were used as control. The natural substrates performed better than the artificial ones. Pistia roots gave the best mean hatching rate of 66.2 ± 3.62%. Green grass leaves were second with a mean rate of 54.0 ± 3.46%, water hyacinth was third with 49.7 ± 3.16% and Ceratophyllum fourth with a mean of 13.0 ± 2.37%. Concrete slabs gave a mean rate of 18.6 ± 2.8%, sisal mats 18.6 ± 2.0%, papyrus 12.2 ± 1.2% and kakaban 11.8 ± 1.9%. Nylon mats were the last, with a mean rate of 4.0 ± 0.7%. The best performing natural substrates were those with the ability to float and thin fibrous roots that seemed to allow higher aeration of the eggs during incubation. The cost of using natural substrates was minimal.

A report on frame and catch assessment surveys on Lake Nakuwa, Lake Kyoga Basin, Uganda

Lake Nakuwa is one of the large lakes among the Kyoga drainage system lakes, located 132 km north east Off Jinja town, at 01° 091N 33° 21 1 E, an elevation 1037 m, surface area of 200 km2 and an average depth of 3.3 m. The lake is shared by the districts of Kamuli, Pallisa and the newly created district of Kaliro. howerever 80% of the landing sites are in Kaliro and less than 20% are shared between the districts of Kamuli and Pallisa. The lake is free of submerged and floating macrophytes, with lots of floating papyrus (sudds). Papyrus, hippo grass and reeds dominate the shoreline vegetation. Lake Nakuwa like the main lake Kyoga was stocked with the Nile perch and the tilapiine species namely Oreochromis niloticus, Oreochromis leucostictus and Tilapia zillii in the general stocking exercise of small lakes alild dams in the early 1970's.

The fisheries of Lake Wamala: a report on the fisheries resources surveys conducted during 1975/78 and 1988/92

Lake wamala was opened to commercial fishing in 1960. Interviews with the local fishermen during 1975/78 (Okaronon 1975, 1976, 1977, 1989) revealed that fishing for subsistence had been going on long before stocking was done. The subsistence fishing was conducted along rivers and at river mouths using basket traps (mainly made of papyrus stems), weirs and hooks and that the fish species caught were predominantly clarias (mudfish/male) and protopterus Lungfish/Mamba). These interviews did not, however, reveal the presence of tilapiine species in Lake wamala prior to stocking. These interviews did not however reveal the presence of tillapine species in lake wamala prior to stocking. Following the opening of the lake to commercial fishing in 1960, Lake Wamala provided a very profitable commercial fishery throughout the 1960s. However, during the early 1970s the fishermen started complaining of continued decline in catch rates from about 8 kg (15 fish) of O. niloticus per net per night if in 1966 to less than 1 kg per net per night by 1975.

The diversity of amphibians, reptiles and mammals and their importance in the Victoria and Kyoga lake basins

The shore margins of Lakes in the Victoria basin are highly dented and mostly swampy, fringed by Papyrus and other wetland vegetation types important habitats for herpetofauna and wetland adapted mammals. Of recent, the extent of the 'wetland' has been extended in several places by the Water Hyacinth (Eichornia cryaseps). Ecologically, amphibians are important in many ways; they are mostly predators, acting as primary and secondary carnivores. Their prey consists mostly of insects, some of which are pests to crops or disease vectors. They are also inter-inked in food chains, often acting as food for other vertebrates, such as pigs, birds, snakes and sometimes man. Because of their ectothermic physiology, the life history and ecology of amphibians often differ markedly from that of birds or mammals (McCollough el ai, (992).Amphibians are known to be an easily recognisable taxon in given habitats; and populations are sometimes specialised within a narrow habitat. This makes it easy and practical to monitor changes in composition over time, given different onditions (Heyer el al 1994, Phillips 1990). Impacts on their habitat are reflected in changes in numbers and species diversity in a short time. These are some of the factors that have made amphibians to be recognised, nowadays, as good indicators of habitat change

Trolling for Nile perch (Lates niloticus) in Lake Kyoga

Nile perch were introduced into Lake Kyoga in the mid·1950s from Lake Albert. Murchison Falls on the River Nile, between the two lakes, prevented Nile Perch and other elements of the typical nilotic fish population from naturally reaching Lake Kyoga. The introduction has been successful and considerable stocks of Nile Perch now exist in Lake Kyoga. In 1967, 13,000 tons of Nile Perch were estimated to have been landed by the commercial fishermen, fish of 200 lb. being now caught and specimens of 100 lb. being fairly common. Large Nile perch are caught commercially on long lines baited with live Protopterus' spp. or Clarias spp. Large mesh gillnets uccasionally take Nile Perch of up to 30 lb., but the high cost of the nets does not, at the moment, appear to justify this method of fishing; a 10 in. net, stretched 100 yards long (unmounted). 15 meshes deep and 60-ply nylon. costs approximately U. Shs. 300. The long·lines used are extremely simple and cheap to make, but considerable labour is needed to catch bait. Small Protopterus are normally caught by turning over floating rafts of grasses and papyrus, and extracting the fish from the root mass; this is hard and dirty work. Other small fish, more readily available, do not, according to fishermen, work as well, possibly because they are not as durable as the Protopterus or Clarias. Dead bait is never used.

Increase in fish production achieved by stocking exotic species (Lake Kyoga, Uganda)

The Lake Kyoga complex lies towards the north of Uganda, at 311 altitude of 3,400 feet, between 10 and 2° north of the Equator. The lake is extremely elongate and digitate, shallow (1 metre-7 metres), and almost all the coast-line is swampy, with many papyrus beds. Floating islands of sud are a feature. At its eastern extremity, it breaks up into many swampy, isolated lakes. The Nile from its source at Jinja enters Lake Kyoga on its southern side, and leaves the lake at its western extremity, and winds on through to Lake Albert and the Sudan. The Kyoga/Salisbury /Kwania complex covers 2,354 sq. km. of water. Geologically, the lake is a series of flooded river valleys, probably resulting from the uplifting of the western edge of the basin in the Pliocene and the Pleistocene ages aud the endemic fish fauna is very similar to that of Lake Victoria, although Kyoga has not developed the species flocks of haplochromis which characterise the larger lake. The Victoria fauna extends down-stream of Lake Kyoga to the Murchison Falls on the Nile, which forms an almost complete barrier between Kyoga and the typical nilotic fauna of the Nile below Murchison and Lake Albert.

The potential for further proliferation of water hyacinth in Lakes Victoria, Kyoga and Kwania and some urgent aspects for research

Shore environments of Lakes Victoria and Kyoga with potential for the establishment and proliferation of water hyacinth were identified. They are characterised by: (i) shelter from violent off-shore and along-the-shore wind and wave action (ii) flat or gentle slope under relatively shallow water, and (iii) a muddy bottom rich in organic matter. Such environments are strongly associated with emergent macrophytes of papyrus, Vossia sp and, at times Typha sp where Pistia stratiotes, species of ceratophyllum, myriophylum and nymphaea also occur. In Lake Kyoga association with Vossia sp facilitated establishment of water hyacinth even along wind-swept shores and promoted extension of mats of the two machrophytes into the open lake. Urgent research on water hyacinth is proposed in the areas of nutrient relations, weed biology and on its impact on the biodiversity resource, with particular emphasis on the fishery component. Findings from the research could facilitate formulation of weed control options and alternative resource management strategies. A regional approach to address the water hyacinth menace is highly recommended.

Lakes Wamala and Kijanebalola: evaluation of the fisheries resources during July 1975

This report presents the results of the second (in 1975) fisheries resource survey for Lake Wamala conducted from 10th to 16th July 1975. The first similar survey covered the period 14th to 20th May 1975. The areas sampled consisted of the river-month areas, the papyrus-fringed inshore waters and the open dee offshore waters. In an effort to find the possible major causes of the decline in catch and seasonal disappearance of fish-hence a solution to the problem(s)-a second fisheries resource survey using multifilament nylon gillnets was conducted on Lake Kijanebalola during the period 17th to 21st July 1975. The first survey was similar and covered the period 21st to 27th May 1975.

The role of satellite lakes in conservation of fish species diversity in the Lake Kyoga basin

Lakes Victoria and Kyoga had, a diverse fish fauna, which was important as food for local population and valuable in scientific studies. Over the past twenty years, the diversity of fish in these lakes had declined due to over-exploitation, introduction of new fish species including the piscivorous Nile perch and degradation of fish habitat. Studies of satellite lakes in the Victoria and Kyoga lake basins suggested that some of these lakes harboured species which had been lost from the main lakes. In order to better understand the extent, to which these satellite lakes may serve as refugia, a faunal survey was undertaken to determine the distribution and nature of the taxa found. Seven satellite lakes and the eastern end of the main Lake Kyoga adjacent to these minor lakes were surveyed over a two-year period for fish species diversity. A total of 68 fish species were recorded of which 41 were haplochromines. Almost all the native non cichlids which occurred in the main lakes (Victoria and Kyoga) before the Nile perch upsurge recorded. Lakes Nawampasa, Gigati, Kawi, Agu and Nyaguo had the highest fish species and trophic diversity. The trophic diversity of haplochromines (based on Shannon Weaver Index) was highest in Lake Nawampasa (1.28), followed by Gigati (1.25), Kawi (1.18), Agu (0.8), Lemwa (0.81), Nyaguo (0.35) and was lowest in the main Lake Kyoga. Potential threats to these lakes were from collectors of ornamental fish species, especially the haplochromines, the spread of the predatory Nile perch and the water hyacinth, which are already in Lake Kyoga, and the destruction of macrophytes through harvesting of papyrus and reclamation for agriculture. The human population around these lakes harvested the fishes for food but the levels of exploitation were still low because the lakes were adjacent to main Lake Kyoga, the major supply of fish. Ornamental fish dealers were encouraged to start captive breeding of the fish for export to reduce pressure on the lakes and demonstrations for breeding were set up at FIRI in Jinja. Meetings and seminars were held with some of the communities living around the lakes sampled and the importance of fish species found in these lakes and the dangers of destructive practices discussed. Representatives of all taxa of fish caught from the lakes were preserved, catalogued and stored in the FIRI Museum. Results from this survey support the motion that these satellite lakes are important refugia for endemic diversity. Based on survey, we recommend that SaIne of these lakes like Nawampasa, Gigati, Kawi, Agu and Nyaguo could be designated as conservation areas of species threatened in the main lakes. One of the factors that seem to have prevented the spread of Nile perch into Kyoga Minor lakes seems to have been the presence of extensive swamps around these lakes and the low oxygen levels that exist in these habitats. Clearing of swamps and vegetation that separate Kyoga minor lakes from the main lake should be avoided to prevent Nile perch from spreading into these lakes.

Status of the beach management units development in Uganda

Fisheries plays a significant and important part in the economy of the country contributing to foreign exchange, food security and employment creation. Lake Victoria contributes over 50% of the total annual fish catch. The purpose of fisheries management is to ensure conservation, protection, proper use, economic efficiency and equitable distribution of the fisheries resources both for the present and future generations through sustainable utilization. The earliest fisheries were mainly at the subsistence level. Fishing gear consisted of locally made basket traps, hooks and seine nets of papyrus. Fishing effort begun to increase with the introduction of more efficient flax gillnets in 1905. Fisheries management in Uganda started in 1914. Before then, the fishery was under some form of traditional management based on the do and don'ts. History shows that the Baganda had strong spiritual beliefs in respect of "god Mukasa" (god of the Lake) and these indirectly contributed to sustainable management of the lake. If a fisherman neglected to comply witt'l any of the ceremonies related to fishing he was expected to encounter a bad omen (Rev. Roscoe, 1965) However, with the introduction of the nylon gill nets, which could catch more fish, traditional management regime broke down. By 1955 the indigenous fish species like Oreochromis variabilis and Oreochromis esculentus had greatly declined in catches. Decline in catches led to introduction of poor fishing methods because of competition for fish. Government in an attempt to regulate the fishing irldustry enacted the first Fisheries Ordinance in 1951 and recruited Fisheries Officers to enforce them. The government put in place minimum net mesh-sizes and Fisheries Officers arrested fishermen without explaining the reason. This led to continued poor fishing practices. The development of government centred management systems led to increased alienation of resource users and to wilful disregard of specific regulations. The realisation of the problems faced by the central management system led to the recognition that user groups need to be actively involved in fisheries management if the systems are to be consistent with sustainable fisheries and be legitimate. Community participation in fisheries management under the Comanagement approach has been adopted in Lake Victoria including other water bodies.

Water quality assessments in the Opeta-Bisina wetland systems and Mburo-Nakivale wetland systems

It is located in eastern Uganda, the wetland system is characterized by open water that is clear with some emergent vegetation mainly of sedges and floating vegetation dominated by the day water lily Nymphaea sp and submerged water weeds. Some patches of Cyperus papyrus exist in areas with minimal agricultural encroachment. The main inflow into the Opeta system is through River Sironko.

Invertebrate communities of Nabugabo Lakes: a vital support resource for the fisheries and ecosystem diversity

A field study of the invertebrate communities of the Nabugabo lakes(Nabugabo,Kayanja and Kayugi)showed the occurrence of copepoda, cladocera and rotifera(micro-invertebrates or zooplankton); Ephemeroptera and Diptera(macro-invertebrates or zoo-benthos). The most commonly encountered taxa were thermocyclops neglectus, moinamicrura,several rotiferan species(micro-invertebrates);P.adusta,chironomus, tanipodinae and trichoptera(macro- invertebrates). These organisms are assumed to be readily available as food sources for fishes in the Nabugabo lakes. Higher abundance and diversity of invertebrates occurred in Lake Nabugabo compared to Kayanja and Kayugi. There were no major differences in diversity and abundance of organisms between inshore and offshore areas of the different lakes. The highest diversity of macro-invertebrates(up to 15 taxa)was recovered from roots of macrophyte(higher water-based plants)such as Miscanthidium and Papyrus. The zooplankton of Nabugabo lakes typify a tropical assemblage with few species among genera and dominance of the communities by small-bodied organisms. Some taxa,common to many other water bodies such as Mesocyclops spp.,Calanoids(Copepoda), Caridina nilotica (Decapoda)were noticeably missing in the Nabugabo lakes community, probably due to environmental limitations including low conductivity and pH. Where they occur,these missing taxa have been shown to be key forage items for fishes and therefore their absence in Nabugabo lakes may have implications with respect to potential for fishery production. However other valuable invertebrate types such as cyclopoid copepods,ephemeroptera, chironomid and chaoborid larvae do occur in sufficiently high diversity and abundance to support viable fisheries resources. The high diversity and abundance of invertebrates associated with aquatic macrophytes such as Papyrus and Miscanthidium need to be protected through control of access and utilisation of shoreline vegetation.

Nabugabo lakes and their current conservation status

Fish species diversity in Lake Nabugabo, Uganda, has declined following establishment of the introduced fish species in the lake. Most of the native fish species have disappeared and the lake is now dominated by the introduced Nile perch, Lates niloticus and the Nile tilapia Oreochromis niloticus. The dominant native fish species include Synodontis afrofischeri, Schilbe intermedius, Rastrineobola argentea and Brycinussadleri. Some of the native fish species that have disappeared from Lake Nabugabo were reported to occur in lakes Kayugi and Kayanja, which are adjacent to Lake Nabugabo but separated from it by extensive papyrus swamps. The Nabugabo lakes are satellite water bodies in the Lake Victoria basin, which is known to have experienced fish species changes due to the introduction of the Nile perch Lates niloticus during the 1960s.The Nabugabo lakes comprising of Lake Nabugabo main, and the smaller lakes Kayanja and Kayugi were investigated between 2000 and 2002 with experimental gill netting to evaluate the potential of these lakes in conservation of fish species diversity. Results show that some native fish species especially Oreochromis esculentus, and Oreochromis variabilis and the haplochromine cichlid Prognathochromis venator that have disappeared from Lake Nabugabo still occur in Lakes Kayanja and Kayugi. Inshore habitats with macrophyte cover were also found to be important habitats for the endangered native fish species in the Nabugabo lakes. These lakes and inshore habitats need to be protected to conserve the endangered native fish species and to reduce further decline in fish species diversity.