Lake Nabugabo: a potential reservoir for mukene (Rastrineobola argentea)

"Mukene"Rastrineobola argentea occurs in lakes Victoria, Kyoga, Nabugabo and the Victoria Nile. On lakes Victoria and Kyoga the commercial fishery is well developed. While some fishing occurs at isolated places on the Victoria Nile, the species is yet to be exploited on lake Nabugabo although the potential exists. Experimental fishing (light fishing and beach seining) was conducted on Lake Nabugabo based at the Lake Nabugabo Holiday and Conference Center. Specimens obtained were analyzed for biological and fisheries parameters. Mukene on Lake Nabugabo still grows to a large adult size compared to the Lake Victoria populations. Size at first maturity at 42mmSL is close to that observed on Lake Victoria. Peak breeding occurred between August and January. Unlike on Lake Victoria, R.argentea in Lake Nabugabo is not infested by the cestode Ligula intestinalis that is common in these fishes. Catch rates of 9.8 kg/lamp/hr by the lampara net on this lake compare favorably with many parts of Lake Victoria and on Lake Kyoga where a commercial fishery exists. The amount of by-catch species in the catches however is high and does not therefore favour the establishment of the fishery on this lake. Human exploitation of mukene on Lake Nabugabo would also affect the Nile perch fishery which depends on the species as a source of food.

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.

Socio-economic aspects of Nabugabo satellite lakes, fisheries and their implications for management

A number of fish species once native only to Lakes Victoria and Kyoga have considerably declined over the years, and in some cases disappeared, due to over exploitation, introduction of exotic species especially the Nile Perch, and environmental degradation resulting from human activities. Some of the species have been observed to survive in satellite lakes in the Victoria and Kyoga Lake basins. The Nabugabo satellite lakes contain the endemic Cichlid fish species, Oreochromis esculentus and two haplochromine species previously found only in Lake Nabugabo. There is, therefore, need to conserve these species by ensuring sustainable use and management of the resources. The study revealed that the Nabugabo lakes provide a range of socio-economic benefits accruing from fishing, farming, logging, resort beach development and watering of animals. However, although these activities impact on the lakes ecosystems, the participation of resource users in management is limited because of the weak local management institutions operating on the lakes, hence the need to strengthen them through capacity building. It is recommended that Government should work jointly with the beach committees and fishing community in a participatory way to eliminate the use of destructive fishing practices and control the other environment degrading activities.

Investigating illegal fishing practices on Lake George: a case study of Kayinja landing site, Kamwenge District

The study was done at Kayinja landing site, one of the six gazzeted landing sites located on the eastern side of Lake George, Kamwenge district to investigate illegal fishing practices on the lake. The objectives of the study were to identify the fish species most affected by illegal fishing, factors that drive illegal fishing on the lake, impact of illegal fishing to the fishery and livelihoods of the communities around the lake and to find out the prospect of ending illegal fishing on the lake. A participatory approach was used during the study where fishers and fisheries staff were interviewed for the fish species targeted, current management approach so as to find out species at risk and anticipate the prospect or ending illegal fishing respectively also past records of the daily catch ror a period of five years were used to study the trend henee ascertain the impact of illegal fishing to the fishery and livelihoods of the communities around. Results indicated that the most targeted fish hence other wise affected by illegal fishing is Oreochromis niloticus, the most immediate impact being a decline in fish stocks, whereas defining mechanisms to increase fish stocks through closed seasons and implementation of minimum mesh size policy being the prospect to end illegal fishing on the lake.

Investigations of the present factors affecting the population characteristics and relative abundance of nile perch (Lates niloticus) at selected trawling sites of western part of Lake Victoria, Uganda, Kagegi Gulf

This report is based on the investigation of the factors affecting population characteristics and relative abundance of Nile perch in selected sites of Kagegi Gulf Lake Victoria Uganda in the month of November 2006. Nine (9) stations were sampled at depth strata of 0-10, 10-20, 20-30 and 30-40 m the mean catch rates were as follows; 8.75±5.5, 4.77±2.3, 6.33±0.3 and 1.34±1.1 tonnes per square kilometer respectively. The catch rates differed at various depth levels with p-value of 0.2940 at 5% level of significance. Limnological parameters were temperature 25.15±0.28, 23.68±0.20, 24.74±0.13 and 25.3±0.20°C; pH of 8.0±0.00, 7.7±0.11; 7.66±0.33 and 6.32±0.14, dissolved oxygen 7.37±0.24, 6.44±0.30, 6.32±0.14 and 6.22±0.14 mg/l; Total nitrogen 589.82±97.2, 514.34±68.8, 690.44±257.8 and 809.03±45.02 µgL-respectively with a p-value of 0.4392 at 5% level of significance. Prey type of Nile perch indicated 65.2% of haplochromine in 0-10 m depth and other strata >10 metre were dominated by Caridina nilotica. Generally investigations indicated that the catch rates of Nile perch at Kagegi gulf in various depth strata probably depended on both the physical and chemical parameters mentioned above.

The effect of hook size on the catch rate and size of the Nile perch Lates niloticus (Linne) fishery in the Napoleon Gulf, Lake Victoria, Uganda

This study was undertaken in Napoleon gulf, Lake Victoria Uganda from July – December 2009. It was conducted in four landing sites; Bukaya (0.41103N, 33.19133E), Bugungu (0.40216N, 33.2028E), Busana (0.39062N, 33.25228E) and Kikondo (0.3995N, 33.21848E) all from Buikwe district (Formerly part of Mukono district). The main aim was to determine the effect of both hook size and bait type on the catch rate (mean weight) and size composition of Nile perch (Lates niloticus) (LINNE) fishery in the Napoleon Gulf, Lake Victoria. The main hook sizes investigated during the experiment were 7, 8, 9, 10, 11 and 12 that were dominantly used in harvesting Nile perch in Napoleon Gulf, Lake Victoria. In this study length, weight and bait type data were collected on site from each boat at that particular fishing spot; since most fishermen in the Napoleon Gulf could sell their fish immediately the catch is caught there and then. The results indicated a total of 873 Nile perch fish samples collected during the study. Statistical tests, descriptive statistics, regression and correlation were all carried out using the Statistical Package for the Social Sciences (SPSS) in addition to Microsoft excel. The bait types in the Gulf ranged from 5-10 cm Total length (TL) haplochromine, 24.5-27 cm TL Mormyrus kannume and 9-24 cm TL Clarias species. The bait types had a significant effect on the catch rate and also on the size composition the fish harvested measured as Total length (ANCOVA F=8.231; P<0.05) despite the fact that bait type had no influence on mean weight of fish captured (ANCOVA F=2.898; P>0.05). Hook sizes used by the fishers had a significant effect on the both the size (TL) composition (ANCOVA F=3.847; P<0.05) and the mean weight (ANCOVA F=4.599; P<0.005) of the Nile perch captured. Investigations indicated hook sizes seven (7) and eight (8) were the ones that harvested the Nile perch above the slot size of 50 cm total length. In general hook sizes indicated to be the main drive in the harvesting of the Nile perch though bait type also contributed toward that. Generally there is need for management to put a law in place on the minimum hook size to be used on the harvesting of the Nile perch and also monitored by the Fisheries Management as a regulatory measure. In addition to that aquaculture should be encouraged to farm the fish for bait at a higher scale in the region in order to avoid depleting the wild stocks already in danger of extinction. Through this kind of venture, both biodiversity conservation and environmental sustainability will be observed in the Lake Victoria basin.

The effect of Lampara net on the catch rates and size of the fishing harvest of Rastrineobola argentae (mukene) in selected parts of Lake Victoria, Uganda

This study was undertaken in Napoleon gulf, and part of the off shore area of Lake Victoria Uganda in the landing site of Lufu in Buvuma district in the month of October 2015 for three days of sampling. It was conducted in four landing sites; Busana, Kikondo from Buikwe district and Lufu landing site from Buvuma district. The main aim was to determine the effect of Lampara net on the catch rate and size of the Rastrineobola argentae (mukene) harvested on Lake Victoria using various mesh sizes. The study focused on the 5mm and 10 mm mesh sizes of the Lampara net. A total of 109 boats were sampled; from the 5 mm mesh sizes indicated catch rates of 78-200 kg/boat/day and yet for 10 mm mesh size was at 248 kg/boat day. Statistical tests were carried out on the these two mesh sizes using One way Anova and indicated in catches was (Anova F=7.476; P<0.05) and for the price values was (Anova F=5.488 ; P<0.05). This is an indication that despite the fact that the mukene fishery is on the increase, a time will come when it also be depleted so a need to use the rightful fishing gear of 10mm mesh size is advisable for the biodiversity conservation.

The fisheries of the Kyoga lakes and the likely impact on them by human activities in the catchment

A review of the historical development of the fishery resources of the Kyoga basin shows that the fishery based on the alien fishes which surplanted the indigenous species in the 1960's and early 1970's has been evolving. The record catches of the 19705 and early 1980's were mainly influenced by increased nutrient supply and enlarged lake volume. The sudden collapse in the fishery particularly of the Nile perch in the mid 1980's was most probably imposed by bad fishing regimes. However, future trends in the fisheries of the Kyoga basin will most likely be controlled by nutrient availability and dynamics as well as by the impact of mans activities in the Kyoga catchment.

Age, growth, tagging of tilapia spp. and reproductive biology of siluroid catfishes in Lake Victoria

This report encompasses the time period 1 September 1973 through 31 July 1975. The research Officer's tour of duty officially terminated 30 September 1975, consisting of a regular 2-year tour of duty with three month extension of contract. During this time research into age and growth of several tropical species of fishes was conducted. In addition a closely related tagging program was initiated in order to determine both growth and movements of fishes. Lastly, some effort was directed towards aspects of the basic biology of several of the siluroid catfishes. This report delineates the relative effort into and success of the various research projects; presents results of research not previously offered, summarizes findings, and makes recommendations for future research endeavour. Two annual reports along with quarterly reports up to 30 June 1975 have been produced and are on file both at Headquarters in Jinja and the Kisumu Sub-station. These only will be referred to in some instances and built upon in others. Opinions offered, conclusions drawn and recommendation given within this report are solely those of the research officer employed in an official capacity for E.A.F.F.R.O.

Adoption of catamaran fishing method for mukene (Rastrineobola argentea) in off shore waters of Lake Victoria

This report presents information on the development of a system for commercial harvesting of Rastrineobola argentea (Mukene) in Lake Victoria. The objective of this work is to develop a system for commercial Harvesting of Mukene with: •Targeted output above 1,000 kg per working night per boat. •Target area to be off shore waters of Lake Victoria. •Drying under hygienic conditions for production of high quality poultry and animal feeds. •Supply to be continuous with predicable prices

Aquatic weeds hotspots in the Lake Victoria basin Uganda and on Lake Kyoga: implications for their management

Proliferation of invasive aquatic weeds has developed into a major ecological and socio economic issue for many regions of the world. As a consequence, inference on where to target control and other management efforts is critical in the management of aquatic weeds (Ibáñez et al., 2009). Notwithstanding, aquatic systems in Uganda in general and in the basins of Lakes Victoria and Kyoga in particular, have fallen victims to aquatic weeds invasion and subsequent infestation. If these aquatic weeds infestations are to be minimized and their impacts mitigated, management decisions ought to be based on up-to-date data and information in relation to location of infestation hotspots. Aquatic systems in the basins of the two production systems are important sources of livelihoods especially from fish production and trade yet they are prone to infestation by aquatic weeds. Thus, the invasion and subsequent infestation of aquatic ecosystems by aquatic weeds pose a major conservation 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 of Lakes Victoria and Kyoga. The information is expected to guide management of major aquatic weeds through rational allocation of the scarce resources by targeting hotspots.

Frame survey (census of boats and fishing gear) Lake Kyoga and Lake Kwania (Uganda), May-June 1990

The census of a fishing industry is called a frame survey. This is a rather comprehensive term, because there are many aspects of a fishery which one might wish to know. This is illustrated by the report on the partial census executed by the ADP/FS on the southern landings of L.Kyoga during December 1988, which deals with many socio-economic aspects of fishermen's households.

Socio-economic processes on Lake Kyoga: potentials for participatory management and poverty eradication

The purpose of this paper is to review selected socio-economic aspects of the Kyoga basin lakes with a view to assessing, the potehtials within the fishing communities for participatory management and poverty eradication. This paper is based on information obtained from three categories of activities. First a review of existing data and reports was undertaken to establish existing knowledge on the subject and identify the gaps.

Fishing effort and the impact of fishing gears and fishing methods on fishes and fisheries of Kyoga basin lakes

Lake Kyoga at the time of Worthington Survey (Worthington, 1929) was fished by only natives around it. The fishing gears consisted of locally made basket traps, hooks and seine nets made out of papyrus. Fishing was mainly during the dry season as in wet season, the fishers would revert to crop growing. During 1937 to 1950s Oreochromis variabilis, oreochromis esculentus (Ngege) and Protopterus aethiopicus (Mamba) were the most important commercial fish species and contributed over 95% to the total landings until early 1950s when their proportions started to change as a result of changes in fishing techniques. The tilapiines' were then being caught using mainly basket traps and P.aethiopicus was caught in hooks prior to the mid 1950s.

The declining state of the gillnet fishery in Lake Victoria, Uganda

Lake Victoria had a multi-species fishery dominated until the 1970s by the tilapiine and the haplochromine cichlids (Kudhongania and Cordone, 1974). From about 1930 to 1960, the fisheries of Lake Victoria were managed by controlling the mesh size of gill nets. Gill nets of stretched mesh sizes less than 127 mm (5 inches) were prohibited as they cropped immature Oreochromis esculentus (Ngege), the most important commercial species on the lake (Graham, 1929). The catch per night in the legal 127 mm mesh nets was over 30 fish of O. esculentus prior to 1921 but dropped to 6 and 1.5 fish in 1928 and 1954, respectively, (Beauchamp, 1955), indicating overfishing of the stocks. The overall aim of the survey was to determine the available fish stocks being harvested by the gill net fishery. The specific objectives included the determination of the species composition and catch levels. Gill nets of mesh sizes from 25.4 mm (1 inch) to 228.6 mm (9 inches) were used.