A Study on Stock Enhancement/Restocking of the Kyoga Basin Lakes
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A study on stock enhancement/ restocking of the Kyoga basin lakes Item Type monograph Publisher National Fisheries Resources Research Institute Download date 03/10/2021 07:57:04 Link to Item http://hdl.handle.net/1834/35341 A STUDY ON STOCK ENHANCEMENT/RESTOCKING OF THE KYOGA BASIN LAKES .. A REVIEW OF KYOGA BASIN l:AKES Prepared for Ministry of Agriculture, Anirnallndustry and Fisheries (MAAIF) by the Fisheries Resources Research Institute (NaFIRRI) JunE! 2007 PROJECT CONTACT: NATIONAL FISHERIES RESOURCES RESEARCH INSTITUTE (NaFIRRI) P.O. BOX 343, JINJA Tel: 043·1;!048411213S9 Fax: 043-120192; Email: [email protected]; [email protected]. STUDY FINANCED BY AFHlCAN DEVELOPMENT FUND THROUGH THE FISHERIES DEVELOPMENT PROJECT --- ---------- Table of c.>ntents 1, Introduction 2, The Kyoga 6asil') Lakes 3, The Diversity of fishes in Kyoga basin lakes 4 Fish Populatkms in the Kyoga Basin lal<es 5, The Fish Stocks of the Kyoga basin la~es 6, Environmental Features in the Kyoga tasin lakes 7, Water Quality 71, Aquatic macrophytes and weeds 72, Invertebrate fauna 8, Socio-economic Factors in the fisherie,; of Kyoga lakes. 9, Current Fi$eries Management Regim,;s in the Kyoga basin lakes 10. Stakeholder Perceptions 11. Conclusion 2 1. Introduction Increased management attention to the fisheries tn Uganda is fuelled by five major factors: socio-economic demands, human population increase, stock depletion, biodiversity loss and, environmental degradation. Fish exports from Uganda to overseas and regional markets have rapidly increased since the mid 1990s and it is estimated that total exports are worth at least US$ 200m three quarters of the value due mostly to Nile perch exports to overseas markets. Exports to regional markets are dominated by variously processed tilapia "mukene" (Rastrineobo/a argentea), Nile perch "angara" (A/estes baremose) and cat fishes. Virtually all major water bodies contribute to this trade. A combinatilm of exports and an increased human population has seen the per capita fish consumption in Uganda drop from 15kg in the early 1990s to almost 10kg by 2005. this figure is below the WHO recommended fish protein intake of 17kg. the apparent fish gap in a liberalised economic framework has stimulated interest in commercial fish farming. Stock depletion in all water bodies in characterised by illegal fish gears and methods and the capture of immature fish. The excessive fishing effort has not been curbed especially as fisheries management has been delegated to the decentralised governance policy. Under this arrangement, districts are responsible for parts of water bodies under their jurisdiction even though no single water body falls within a single district. The establishment of co-management arrangements (i.e. Beach Management Units) has been considered as a fundamental need to ensure fisheries management and sustainability. However, it is still far too early to predict the extent to which the arrangement will go and with what requirements. A major concern is that the fisherfolk who operate in a market economy can embrace the sustainability philosophy in a decentralised framework that also includes other interested groups in the fisheries and environment from an exploitative perspective. The competing needs and desires could work against sustainable management without a strong central oversight function when the traditional systems (e.g. "Gabunga") are completely 3 ".l"'.~·,.. '. 2. The diversity of fishes in the Kyoga Basin lakes Introduction Kyoga basin lakes are a very important natural resource for the communities within the. lake basin and beyond. Fisheries of the Kyoga basin lakes enable millions of poor fishers, processors and traders to diversify their livelihood strategies on the basin of income while at the same time supplying vast numbers of poor consumers with essential nutrition. Fish is particularly important for the poor as it is often the most readily available and affordable source of protein and other micronutrients crucial to a healthy diet. The lakes also generate substantial revenue to the local governments within their catchment's area,. Thus the fisheries of Kyoga basin lakes are a key instrument in poverty eradication and food security. In addition to employing people around the lakes directly as fishers and fish traders, the fishery of these lakes also indirectly employs a range of other skilled workers such as boat builders, fishing gear fabricators, makers of crafts such as baskets and mats, etc. The lakes also have a great potential as a source of-water and are also used as transport routes. Some of the Kyoga small lakes harbour species which have disappeared from the main lakes Victoria and Kyoga and are therefore important for biodiversity conservation. The native Lake Kyoga tilapiines Oreochromis esculentus and Oreochromis variabilis plus several species of haplochromine cichlids that are threatened with extinction still occur in some of the small Kyoga basin lakes. Based on a survey funded by the USAID Consortium (Ogutu-Ohwayo et al 1999), it was recommended that some of the lakes, especially Nawampasa, Gigati, Kawi, Agu and Nyaguo, be designated as conservation areas for species threatened in the main lakes. However, there is concern that the fish stocks of Kyoga basin lakes are declining and may not be enough to meet the ever increasing demand. Even in lakes where Nile perch was introduced in the 1950s, its biomass has greatly declined and in some lakes, especially Lake Bisina, the species is rarely caught by the fishers. Stock enhancement of some of the Kyoga basin lakes has therefore been proposed as one of the solutions to ensure sustainability of the fishery resources of these lakes. This paper therefore provides a review of the past status of fish species diversity of the Kyoga basin lakes in order to establish which lakes require stock enhancement and with what fish species. Background Fish faunal surveys have been carried out in various small lakes in the Kyoga basin since 1998. Some of these lakes were not stocked with Nile perch and are spatially separated from the main lakes in which Nile perch was introduced by, which provide. The extensive papyrus swamps that surround the lakes act as barrier to Nile perch invasion and other human impacts. Results have indicated that some of the indigenous 4 species, especially Oreochromis eSGulentus and Oreochromis variabi!is, depleted from the main lakes due to Nile perch predation pressure and destructive fishing methods are still present in these small lakes (Ogutu-Ohwayo, et a(1999). Some Kyoga small lakes have a high fish species diversity especially of the haplochromine cichlids. Most of the haplochromine species that have disappeared from lakes Victoria and Kyoga were found to occur in most of the Kyoga small lakes. This may be due to habitat diversity since most are characterized by dense mats of water lilies and other submerged waterweeds that provide refuge to endangered fish species especially the haplochromine cichlids. Some small lakes are therefore suitable for conservation of native fish species since, due to their small size, they can be easily monitored. Many of these lakes can also be closed to fishing since they are close to the main Lake Kyoga which can provide alternative sources of fish protein. The major threat to Kyoga basin lakes is over-exploitation and use of destructive fishing gears leading to decline in fish stocks. In Lake Kyoga, the decline in catches was noted in the 1980s. By 1985 the contribution of Nile perch to the total commercial output was less than 20% compared with about 50% in 1980 (ADP/Fishery Survey" 1992). The decline in the species was attributed to extensive use of both beach and open lake seine nets. Other threats include drainage of surrounding wetlanas for agriculture, collection of ornamental fish for aquarium trade and invasion by water hyacinth. Fish species diversity, especially of Lake Kyoga, has also declined from 43 species recorded in the late 1920s (Worthington 1929) to 32 species recorded in the recent past (ARTP 11, 2005) Study Area The review was based on 13 lakes of the Kyoga basin namely lakes Kyoga, Nawampasa, Kimira, Nakuwa, Gigate, Bisina, Kawi, Lemwa, Nyaguo, Agu, Kwania, Opeta and Nabisojjo. Some of the lakes sampled are shown in Figure 1. The area and average depth of some of the lakes so far sampled is shown in Table 1 5 9 paldwes sallel a4110 awos OU!M04S 'epueon 10 dew laSU! ue 41!M 'sallel lIews eOOA){ allel10 deVIl . ~ amB!:! .0(;:.£(;: n=========I=T=====;;;'='=''''_'===;=~';-=''''==,r..;=,,~~I======''Jr''~~=='''''==== ~ :Q~': N., i ... -:-. ':;:. .: ... No! ..... O4l: o. o dNYMS {,-.--- ..--- - ...... ./ --, " ..... .~ o. ... : '_.)1• ,00. • '\... .... ~ ...... ..'\ ... ">•• ... I.LOWOS •. , • ..., Table 1. Area and averaae depth of lakes sample d___. 2 Lake Area(km ) Averaae depth (m) Kvoaa 2032 3.5 Lemwa 10.4 3.1 Kawi 5.0 3.2 Aou 2.2 2.2 Giaati 6.7 2.4 Nakuwa 73 3.3 Nawamoasa 7.0 2.6 Bisina 141 3.5 Oceta 11.0 Kwania 400 3.5 Kimira .... ? NVaquo 24 2.4 Nabisoiio 6 2.0 Fish Species Composition, relative abundance and Distribution Overall, twenty-seven fish taxa were recorded from all the 13 lakes sampled, including haplochromine cichlids as a single species group as shown in Table 2 (FIRRI, 2000; NaFIRRl, 2005, LVEMP in prep). The highest number of fish taxa was recorded from Lake Nyaguo (19) followed by lakes Bisina, Agu and Kyoga at 17 each, Opeta (15),Nakuwa and Kwania (12 each),Nawampasa (11), Lemwa and Gigati (10 each). Lakes Nabisojjo, Kimira and Kawi had the lowest number of fish taxa (8 each). Protopterus aethiopicus, haplochromine cichlids, Clarias gariepinus, and Oreochromis leucostictus were recorded from all the lakes sampled. Haplochromine cichlids were the most dominant fish taxa in all the lakes except lakes Nakuwa and Nyaquo where the catch was dominated by Synodontis afrofischeri and Brycinus sadleri respectively.