A Study on Stock Enhancement/Restocking of the Kyoga Basin Lakes

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

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

".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

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">•• ... 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. Lates niloticus was only recorded from Lake Nakuwa whereas Oreochromis niloticus was recorded from all lakes except lakes Nyaguo and Agu, although it was most dominant in Lake Nakuwa. O. esculentus was recorded from lakes Nawampasa, Nyaguo, Bisina, Gigati, Lemwa, Kimira and Nabisojjo while O. variabilis was recorded from lakes Opeta, Nawampasa, Bisina, Gigati and Agu. Although S. afrofischeri was recorded from most of the lakes sampled, its contribution to the catches was significantly higher in lakes Bisina and Nakuwa. The contribution of Synodontis victoriae was significantly higher in Lake Nakuwa although it was recorded from several lakes. Bagrus docmac was only recorded from Lake Bisina.

Among the haplochromine cichlids 43 species were recorded from all the Kyoga basin lakes as shown in Table 3. The highest number of species was recorded from Lake Nawampasa (27) followed by lakes Gigati (23), Kawi (20), Agu and Bisina (17 each), Nyaguo (16), Kyoga (15), Opeta (12), Kimira (9), Kwania (8) and Nakuwa (4). Haplochromine cichlids from Lake Nabisojjo were not identified to species level

7 Gaps • Information on the current status of the fish species diversity in the Kyoga basin is lacking • Information on some of the Kyoga small lakes is not available

Recommendations • Lakes that contain the endangered fish species, especially O. esculenlus, 0.· variabilis and several haplochromines that are considered extinct in the main lakes Kyoga and Victoria, should be designated as conservation areas, • Some of the lakes without endangered native fish species should be considered for stock enhancement • Baseline surveys should be carried out in the lakes where information is lacking. • InformatioR on the current status of the fish species diversity in the Kyoga basin lakes should be collected through surveys in order to identify the most suitable species to be used in stock enhancement for each of the lakes.

8 Species Kyoga Opela Nawampasa Nabisojjo Kimira Bisina Nakuwa Kwania Lemwa Kawi Gigale Nyaguo Agu L.n 65.9 0 0 0 0 0 12.8 58.2 0 0 0 0 0 Hap 8.5 339 26.9 1.3 13.3 24.2 11.0 13.9 89.3 69.4 53.9 44.2 19.4 O.e 0 0 10.7 40.2 10.1 0.1 0 0 0.3 0.2 0 2.2 0 0.1 0.2 0.5 3.5 1.7 0.4 08 1.8 0 2.3 0.4 4.5 0.9 2.9 On 3.4 166 11.9 1.6 2.9 10.7 3.7 2.2 0.3 0.1 0.3 5.1 0.6 O.v 0 20.6 13.7 0 0 2.6 0 0 4 0 0 1.5 0 2.9 T.z 0.1 4.7 1.5 0 0 4.9 0 22 0 0 0.2 0 7.5 GI 0 19 0 0 0 0 0 0 0 0 0 0.5 12.6 G.v 0.01 1.2 0 12.0 0 0.2 1.8 0 0 0 0 1.1 4.5 M.g 0.1 1.6 0 0 0 0 0 1.6 0 0 0 0.4 7.4 M.n 0 0.9 0 0 0 0 0 0 0 0 0 0.1 0.2 M.m 0.1 11 0 0 0 0 0 0 0 0 69 4.1 M.k 0.02 0 0 0 0 0 0 0 0 0 0 7.1 0 P.c 0 0 0 0 0 0 0 0 0 0 0 3.9 2.1 C.I 0 0.9 0 0 0.4 0 4.6 0 0 0 0 0 0.4 Cg 0.4 7.6 17.9 30.7 65.6 18.1 0.9 0.6 29 0.4 0.3 9.5 6.9 B.s 1.4 5.9 3.6 0 0 10.5 0 15.5 0 0 28.2 1.2 0 B.d. 0 0 0 0 0 35 0 0.3 0 0 0 0 0 B.a 4.4 0 0 0 0 0 128 1.3 0 0 0 0 0 B.p 0 0 0 0 0 0.1 0 0 0.3 0 0 0.7 0 B k. 0 1.9 0 0.03 + 1.1 0 0 2.3 01 0.1 0.1 0.2 Pa 0.8 0 6.2 122 7.3 2.7 2.7 0 + 29.3 10.2 0.1 14.9 S.a 6.3 0.4 29 0 0 146 32.1 3.2 0.3 0.2 05 2.4 9.7 S.v 7.9 0 1.3 0 0 4.1 14.7 0.3 1'.0 0 0 28 3.5 5.; 0.5 0 0 0 0 1.7 3.7 0.6 0 0 0 0 0 C.m 0 0 0 0 0 0.1 0 0 1.0 0 0 0 7.1 A.I 0.1 0 0 0 0 0 0 0 0 0 0 0.4 0 No. 01 17 15 11 8 8 17 12 12 10 8 10 19 17 species Table 2. The overall percentage composition of fish species from different lakes in the Kyoga Lake Basm

Note: Lakes Nakuwa, Bisina and Kwania were stocked with Nile perch in the 1950s

9 Key L.n =Lates niloticus" Hap. =Haplochromines" O.e = Oreochromis esculentus, 0.1 =Oreochromis leucostictus, O.n = Oreochromis niloticus, O. v = Oreochromis variabilis, T.z = Tilapia zillii, G, I = Gnathonemus longibarbis, G. v = Gnathonemus victoriae, M. g =Marcusenius grahami, M. n =Marcusenius nigricans, M.k =Mormyrus kannume, M. m = Mormyrus macrocephalus, P.c =Petrocephalus catastoma, C. I =Clarias liocephalus, e.g =Clanas gariepinus, B.s = Brycinus sadleri, B.d =Bagrus docmac, B.a =Barbus altianalis. B,p =Barbus palludinosus, B.k =Barbus kestern, P.a = Protopterus aethiopicus, S.a =Synodontis afrofischeri, S.v =Synodontis victoriae, S.i =Schilbe intermedius, ,C.m = Ctenopoma murieri. A.f = Afromastacembelus frenatus

10 Table 3 The overall percentage composition of haplochromines by number from KvoQa lake basin. Lakes Species Kyoga ILemwa IOpeta Kwania Kawi AgulNyaguo Gigati/Nawampasa INakuwa IKimira IBisina IAslaloreochromis alluaudi 0.31 071 0.71 01 1.21 3.21 0.51 091 0.21 01 01 0.5 Aslaloli/apia /atilaseiala 01 01 271 01 010.61 01 0.61 141 01 01 2.6 Aslalolilapia marlini 01 all 01 01 01 01 4 0.71 0.11 01 01 0.21 a Aslaloli/apia nubi/a 25.91 22.91 01 01 8.71 3.21 25.81 0041 0.31 2.21 01 0.1 Aslatoti/apia "miniblack" 01 0.1/ 0.71 01 01 7.91 01 0.71 5.91 01 01 0.8 Astatoti/apia "Iattoth" 01 54.71 271 01 6404/ 17.61 49.11 26.21 39.1/ 01 1.1/ a Aslatoli/apia "maerops" 01 01 01 01 0.21 01 1.51 0.31 0.11 01 01 a Aslalolilapia "Ihieklipped" 23 ~ ~ 01 01 1 01 01 01 01 01 a Astasloti/apia "kyogaaslato" 6.9 a 0.7 72.7 a a aO.lt-- a 02 72.5 0.1 a Gaurochromis sp 0.11 01 01 01 01 01 01 01 0.21 01 01 a Haplochromis /ividus

0.1 f------.-.:.~----=~----=~-~.:+..--:::~-___;~---=~--~~--:+_...:.:::..:+~~ Lipochromis "blaekeryptodon" 0.1 Lipochrom;s cryptodon 01 01 0/ 01 0041 01 0.51 0.11 01 01 01 03 Lipochromis microdon 01 01 01 01 0.21 0.61 01 0041 0041 3.31 01 0 Lipochromis obesus 0\ 01 0.71 01 271 4.81 0.51 0.91 0.61 01 01 0.1 Lipochromis parvidens 0.11 0\ 01 01 0.21 1.91 01 1.21 0.91 01' 01 004 Lipochromis "white" 01 01 01 01 0.21 01 01 01 01 01 01 a Lipochromis maxillaris 01 01 01 01 0.31 061 01 0.1/ 0.5/ 0/ 01 004 Harpagochromis michaelli 01 01 1041 01 01 01 01 01 01 01 01 0 Para/abidoehromis "bJaekpara" 40.71 6.81 01 45\ 141 01 • 01 0.11 01 21.91 0041 0 Paralabidoehromis"redlin" 01 0.11 01 01 0.61 01 01 031 0.61 01 01 0 Paralabidochromis "deep body" 01 01 01 0101 01 01 01 1 01 01 01 01 Prognalhochromis argentus or-O.6 2.7 0 204 5.1 a 0.5 4.8 a 0.3 5.5 Prognalhochromis "long lowerjaw piscivore" 01 01 01 01 01 01 0.51 011 01 01 0/. 0 Prognathochromis pellegrini 01 0/ 01 01 01 2.6/ 01 01 381 01 01 1,8 Prognathochromis "si/verma/e" 01 01 0101 01 01 1.91 01 01 01 01 0 Prognathoehromis "black red lai/ piscivore" 01 01 01 01 01 01 0.71 01 all 01 010 Prognathochromis "stilleto" 01 01 271 231 0.11 031 01 0\ 1.91 01 01 1.6 Prognathochromis "shove/mouth" 19.31 01 5.51 2.31 8.31 221 13.91 1.61 2.91 01 01 2.3 Ptyoehromis "gigalishelle(' 01 01 0101 01 01 0.3/ 0.11 0.11 01 01 a

II Lakes Species Kyoga Lemwa Opela Kwama Kawi Agu Nyaguo Giga!i Nawampasa Nakuwa Kimira Bisina Ptyochromis sauvagei 0 0 0 4.5 0 0 0 0 0 0 0 0 Pyxichromis orthostoma 03 04 0 4.5 4.4 0 1.9 0.3 0.4 0 1.2 0.4 Paralabidochromis "victoriae" 0 0 0 0 0 03 0.7 0 0 0 0 04 Xystichromis phytophangus 03 0 64.4 0 0.2 5.1 0 20.8 2.3 0 0.4 2.4 Yssichromis "Iemwa looplanktivore" 0 0.2 0 0 0.2 0 0 00 0 0 0 0 Yssichromis "kyoga loopJanktivore" 0.4 0 0 0 0 0 0 0 0 0 0 -0 Paralabidochromis "earthquake" 2.3 0 0 0 0 0 0 0 0 0 0 0 Prognathochromis guiarti 07 0 0 0 0 0 0 0 0 0 16.0 0 Xystichromis "flame back" 2.4 0 0 0 0 0 0 a 0 a 0 a ParaJabidochromis "si/verpara" . 0 0 0 a 0 0 a 0.1 0 0 0 0.6 Haplochromis 'unicuspid" 0 a 0 0 0 0 0 0 0.1 a 0 0 Astatotifapia "redtai/fattoo/h" 0 0 0 0 0 0 a 0 0.1 a 0 0 Ast8totilapia "pseudomartini" 0 0 0 0 0 0 0 a 0.2 0 0 0 Grand lolal 15 9 12 8 20 17 16 23 27 4 9 17

12 3. Population and Characteristics of Commercial Species in Kyoga Basin lakes

Background

The Kyoga complex comprises of two major lakes i.e. Lake Kyoga and Lake Kwania, with open water areas of 2032 km 2 and 400 km2 respectivelr; two medium-sized minor lakes (Bisina and Nakuwa with an area of 141 km 2 and 73km respectively) and over fifty other minor lakes. The lakes are surrounded by extensive wetlands fed and drained by a complex network of streams and rivers. The main inflow is from Lake Victoria via the Victoria Nile. Another important source of water is Mt Elgor) region to the East draining through two mai.Q arms; the Mpologoma in the south east and through the Teso swamps in the North East. The outflow is by the Victoria Nile to Lake Albert.

Although the lakes in the Kyoga system contain some fish species that are not present in Lake Victoria, the majority of the species are also found in the inshore habitats of Lake Victoria (Worthington 1929, Greenwood 1966). Just like on Lake Victoria, the original fish fauna -of Lake Kyoga had evolved a trophic diversity that promoted efficient utilization of most of the available energy resources (Twongo 1998). Tilapiines and phytoplanktivorous haplochromines were the major primary converters. Rastrineobola argentea preyed on zooplankton, while the major invertebrate/benthos feeders were Clarias sp., Schilbe intermedius, Synodontis spp., Protopterus aethiopicus, Labeo victorianus and several mormyrids. The major predator was Bagrus docmak.

Because of the relationship with the fish fauna of Lake Victoria, biological studies on the fish species in the Kyoga Basin have been assumed to be similar to those in Victoria. Little specific effort has been directed at studying the fishes from these lakes. There are however some differences in biological attributes between similar species in the two systems. Worthington (1929) noted that fishes in Lake Kyoga tend to grow to a smaller adult size that similar species in Lake Victoria. This means that all size related parameters such as size at maturity, fecundity etc are different for similar species on Lake Kyoga and Victoria.

The earliest survey (Worthington op. cit.) indicated that the indigenous fishery consisted mostly of the native tilapias Oreochromis escu/entus and O. variabilis, the cat fishes Clarias gariepinus, B. docmak, Synodontis victoriae and Schilbe intermedius and the lungfish P. aethiopicus. The introduction in the early 1950's of foreign fish species the Nile perch Lates niloticus, Nile til apia Oreochromis niloticus and two other tilapiine species T. zillii and O. leucostictus strictly into Lake Kyoga and a few smaller lakes, has completely changed the lake ecosystems in those lakes. Their fisheries are now dominated by these introduced species. In lakes e.g. Lake Kyoga and Lake Kwania where occur the introduced species Mukene R. argentea is the only native species of commercial importance. In lakes where the Nile perch is not established the artisanal fisheries consist mainly of the native species 0. esculentus, O. variabilis, C. gariepinus and P. aethiopicus. Species that grow to a small adult size such as the haplochromines,

13 Synodontis mormyrids etc abound in lakes where the predatory Nile perch is not established though they are not sought by the artisanal fishers. This review on biological parameters therefore is restricted to the above fish species that form the main artisanal fishery in the Kyoga Basin Lakes.

Main Biological studies on fishes of the Kyoga Basin Lakes

The earliest comprehensive survey of Lake Kyoga was undertaken by Worthington (1929). This survey was exploratory in nature and documented the existing fish species, methods of exploitation. Some basic biological information on individual fish species (food and feeding, sex structure etc) was also undertaken. The survey covered only the main lakes Kyoga.. and Kwania. Under the Northern Uganda Rehabilitation Program (NURP) of the Agricultural Development Project (ADP) surveys on Lake Kyoga were undertaken between 1986 and 1990. This survey was mainly concerned with the performance of the fishery in the main lakes Kyoga and Kwania. It also did not cover the small lakes associated with Lake Kyoga.

The Nile perch Project supported by IDRC carried out surveys based on the main Lake Kyoga. The survey concentrated on the three most important fish species namely the Nile perch, Nile Tilapia and Mukene on Lakes Victoria, Kyoga and Albert. Biological data were collected on those three species. This survey also did not cover the small lakes of the Basin.

The World Wide Fund (WWF) supported the Biodiversity Support Program on the selected Kyoga Lakes (Ogutu Ohwayo et al 1999). This was the first attempt to go out of the main lake and document what is available in the small lakes satellite to the main lake. In addition to documenting biodiversity, some biological data was collected on the commonest fish species.

The Fisheries Surveys Sub Component of the Lake Victoria Environment Management Project (LVEMP) undertook surveys in the Kyoga lakes to expand on what had been initiated by the WWF survey.

Lake Productivity Project initiated a monthly data collection from commercial catches based at Bukungu on Lake Kyoga. Catch information and biological data for Lates niloticus, Oreochromis niloticus and R. argentea were collected and reported in the FIRRI Lake Kyoga Stake holder's Workshop (2000).

Data has also been collected under the ARTP II research themes covering Lake Kyoga, Lake Kwania and Lake Nakuwa (NAFIRRI Thematic Report 2006). NAFIRRI has from time to time undertaken sampling trips under various programs. A number of students have undertaken studies in specific aspects of the Biology of some fishes in these waters as a fulfillment of various degree awards (Ogutu-Ohwayo 1984, Ogutu-ohwayo (1994) Kadumukasa 1999, Mbabazi 1999, Nagayi 1999).

14 Population parameters of some common fish species

The Nile perch Lates niloticus The Nile perch was introduced into the Lake Kyoga in the early 1950's (Kudhongania et al 1988). The species established itself in the main Lakes Kyoga and Kwania and the medium sized lakes Bisina, Nakuwa and Nyasala, where it formed the basis of a thriving artisanal fishery as early as 1965. It is now almost totally eliminated from Lake Bisina although it still thrives in the other lakes. Data available is from the main Lake Kyoga and Kwania. Lake Nyasala could not be sampled as it is inaccessible especially during rainy seasons.

At the peak of the fishery in the late 60's and in the 1970's, the Nile perch in the Kyoga lakes grew to large adult sizes (Ogutu-Ohwayo 1994). With increased fishing pressure, the mean size ol"the Nile perch captured from these lakes has drastically reduced to ... (Table 1). There are therefore signs of over-fishing and the species is almost eliminated from Lake Bisina.

The diet of the species has also changed from predominantly haplochromines to now include its own young (Ogutu-Ohwayo op. cit.). Biological parameters of this species are given in Table 1.

Oreochromis niloticus Like the Nile perch above, the Nile tilapia 0. niloticus was introduced in the Kyoga Basin lakes in the early 1950,s (Kudhongania et al 1988). It is now fairly well distributed in the lakes of the region (Table 1). With the apparent over-fishing observed on the Nile perch, O. niloticus now forms the backbone of the artisanal fishery in the main Lake Kyoga and many other water bodies in the basin where it occurs.

Oreochromis eseulentus Oreochromis eseulentus, with 0. variabilis were the two native liIapiines found in the Kyoga basin lakes before the in trod uction of the alien tilapiines O. niloticus, O. leueostictus and T. zillii. The two constituted the main fishery in Lakes Kyoga and Kwania (Worthington 1929). Their fishery collapsed possibly as a result of over exploitation and through predation by the Nile perch. O. niloticus now occurs in lakes where the Nile perch is not established (Table 1).

Rastrineobo/a argentea Mukene R. argentea occurs only in the main lakes Kyoga and Kwania in the basin. Its requirements for highly oxygenated waters could have been responsible for its failure to cross the low oxygen swamps into other water bodies in the region. It is now among the leading fish species of commercial importance on the lake. Originally R. argentea in Lake Kyoga grew to and matured at a smaller adult size than on Lake Victoria. When a light fishery was introduced onto the lake round about the year 1994 and most of the original stocks were fished out, the subsequent stocks now looked and behaved similar to those in the inshore habitats of Lake Victoria.

15 Clarias gariepinus Clarias gariepinus (Male) one of the species native to the basin, occurs throughout the Kyoga Basin Lakes. Because it grows to a large adult size, it is popular among the people in the region. The species is able to live in waters with extremely low oxygen level thus its ability to spread and establish populations in essentially in all water bodies in the country. Biological parameters of the species are given in Table 1.

Protopterus aethiopicus The African lung fish P. aethiopicus also occurs throughout the Kyoga basin lake where is a delicacy among the fishers in Teso. It grows to a large adult size and is able to withstand periods of drought in swamps and streams where it occurs by aestivation (Greenwood 1966). ... Gaps

Availability of biological data on fish species in the small lakes in the Kyoga basin has tended to rely on individual interests and objectives of the scientists especially the students concerned. It is also governed on the accessibility of particular lakes and the amount of stocks of a particular fish species available. There is for example good amount of data on O. esculentus from Lakes Nabisojjo, Lemwa and Kawi (Nagayi 1999). Although O. niloticus is available in most of the lakes their numbers may be so low in some lakes that it ;s difficult to obtain enough data on it. It is therefore apparent that there is need to target specifically biological data collections from these small lakes to supplement the little available.

16 TlaDle 1. tliOlogicai parameters ot commercially Important tlsh species In the Kyoga Basin trom experimental catc,h , __ Species Water body Size range Mean Condition Sex Size at 1st Main diet (Mean length) Factor Ratios maturity CmTL M:F Lates niloticus Main lakes 8-77(17) 1.17 1: 0.4 Males-45 Caridina, Odonata (Kyoga & Females= 60 and fish Kwania) (haolochromines) Small Jakes 10-34(17} 1.14 1: 0.4 M - 57, F =1\11 Caridina, Odonata and caught fish (haplochromines) immature Oreochromis Main lakes 9 - 39 (22) 2.11 1: 0.6 23 Detritus, & blue-green niloticus alcae. Small lakes 8-38(15) 1.72 1: 0.5 17 Detritus & Blue-green alcae Oreochromis Small lakes 6-22(12) 1.85 1: 0.5 16 Diatoms & Blue-green esculentus alcae Rastrineobo/a Main lakes 23 - 48 (35}mm 1.63 1: 0.7 3 Zooplankton and argentea lakeflv larvea

C/arias gariepinus Main lakes 11-77(51) Little data L~tle Little data Fish & Poyilla data Small lakes 18 -73 (38) 0.72 1: 1.3 26 Lake-fly larvae & fish (haolochromines) Protopterus Main lakes 11 - 91(51) 0.32 1: 1 44 Mollusks & Fish aethiopicus Small lakes 33 80 (48) 0.30 1: 1 35 MOllusks & Fish

17 4. Review of the past and present status of the fish stocks and fisheries of the Kyoga basin lakes

Introduction

The analysis of fishing inputs and outputs, as well as the information on the biological processes that link inputs and outputs and the biological response of the stocks to exploitation pressure are essential to understanding the status of a fishery and prediction of future yields. The collection of such fisheries information on the Kyoga basin lakes has always been irregular and short term. The fisheries of Lake Kyoga and to some extent Lake Kwania have been fairly well studied compared with· the rest 50+ minor lakes in the Kyoga basin. The major setback relating to the available information on lakes Kwania and Kyoga is the ambiguous reference to the two lake systems. In many cases literature on the two lakes appears as if it is referring to only Lake Kyoga.

Lake Kyoga and 'Kwania' fisheries

Lakes Kyoga and 'Kwania' had a native fish fauna similar to that of Lake Victoria (Graham 1929, Worthington 1929) and have gone through a history similar to that of Lake Victoria (Ogutu-Ohwayo, 1994). The most important commercial fish species at the time when the first fishery survey of these lakes was done by Worthington (1929) up to the early 1950s were endemic Tilapia (0. variabilis and 0. esculentus), Lung fish (P. aethiopicus), and Cat fishes (Bagrus and C/arias) which together contributed 95% of the commercial fishery. Haplochromines were abundant in these lakes but, were not commercially exploited. Before the introduction of efficient and sometimes more distructive fishing gears and methods fishing on lake Kyoga and 'Kwania' was characterized by primitive fishing methods e.g. employing basket traps, locally made hooks and primitive seine nets made from papyrus stem (Stoneman & Rogers, 1970). The Kyoga and 'Kwania' native Tilapia were much smaller than those from Lake Victoria, and 2%" to 3%" gill nets were commonly used. The native fishery was over-exploited in the first half of the 20th Century and this was followed by introduction of the Nile perch and several tilapiine species to rejuvenate the fisheries in the 1950s (Ogutu-Ohwayo 1990).

After establishment of the Nile perch, total fishery yield in lakes Kyoga and 'Kwania' increased from 18,000 tonnes in 1964 to 167,000 tonnes in 1978 due to the rise in the contribution of Nile perch from approximately 700 tonnes to 71,000 tonnes respectively (Table 1). However, the yield of Nile perch later decreased to 15,000 tonnes by 1989 suggesting that Nile perch could not sustain the high yields realized soon after its establishment in the new habitats. Inadequate fish catch statistics and other fisheries data ware collected on the booming fishery of Lake Kyoga and 'Kwania' in the 1970s and as a result, the information of ecological dominance of O. niloticus and L. niloticus over the native fishes was inadequately documented. Consequently, when a decline of catches was noted in the early 1980s, it was attributed to reduced fishing effort resulting from lack of fishing gears

18 rather than a decline of fish stocks. However, the decline of fish yields was real, especially L. niloticus, which by 1985 constituted less than 20% of total commercial catches in Lake Kyoga compared with approximately 50% in 1980 (Marriott, et. al 1988). During the period of establishment of the introduced fish species, the average weight of the Nile perch and O. niloticus increased from the 2.41 kg and 0.89 kg in 1968 to 7.7 kg and 1.4 kg in the early 1880s respectively, despite the large increases in fishing effort. The introduced 0. niloticus eventually become the single dominant species in the fishery. The decline of Nile perch stocks has been attributed to heavy fishing pressure, intensive use of destructive fishing gears and methods especially beach seines, and reduction in food supply (Ogutu-Ohwayo, 1990). A notable decline was recorded for one endemic species, Bagrus docmak for which, total landings reduced from 223 tonnes in 1961 to only 4.5 tonnes in 1968. Prior to establishment of Nile perch, Bagrus had been an important fistf predator whose populations reduced tremendously with Nile perch establishment. During the period of establishment of the introduced fish species, the average weight of the Nile perch and 0. niloticus increased from the 2.41 kg and 0.89 kg in 1968 to 7.7 kg and 1.4 kg in the early 1880s respectively, despite the large increases in fishing effort.

Table 1. Estimated fish production (tonnes) for lakes Kyoga and 'Kwania' in 1963 1989.

Date Naturally Other Introduced tilapias Introduced Total occurring tilapia Naturally (0. nilotica, T. zillii Lates weight (0. esculentus occurring fish and O. niloticus fish and O. variabilis) species leuGostictu) 1963 6,002 9,807 742 Not recorded 16,551 1964 5,929 11,086 589 657 18,261 1965 3,595 9,539 517 4,374 18,025 1966 2590 8618 947 7,422 19,577 1967 2,172 5,716 5,017 13,000 25,905 1968 1,617 5,994 7,644 17,725 32,~ 1969 2,158 6,696 13,166 26,920 48,940 1970 2,545 9,186 16.511 33,828 62,070 1971 8,200 35,900 44,000 88.100 1972 1973 5.100 33,200 59,300 97,600 1974 4,300 39.100 59,400 102.800 1975 52,000 57,300 118,600 1976 50,200 70,900 142,700 1977 73,800 71.000 165,100 1978 73,800 71,000 165,200 1979 Ii 1980

19 1981J 1982 1983 1984 1985 4950 80960 17090 103,000 1986

I 1987 3590 40840 13271 57,701 1988 6144 66281 14~~ f- 86,J£ 1989 2447 37148 I 15111 54,706 --Questionable estimates Fish species diversity.. in lakes Kyoga and 'Kwania'. Before establishment of the Nile perch, up to 14 fish species occurred in the commercial catches. After its establishment, the number of exploited fish species decreased to three, Nile perch, Nile tilapia and one native species - Rastrineobola argentea (Mukene). Although the original decline of the native fish species was due to over fishing, Nile perch predation was largely responsible for further decline of the native species after its establishment. From 1991 stocks of haplochromines and other native species started to increase in Lakes Kyoga and 'Kwania' (Ogutu Ohwayo, 1994). This seems to be due to the reduction in predation pressure as a result of over-fishing of Nile perch and the increase in cover from predation provided by the expansion of the water hyacinth (Kitchell et al., 1997).

Changes in fishing effort in lakes Kyoga and Kwania

The fishing effort on lakes Kyoga and Kwania has been on the increase based on fisheries department records and frame surveys. The frame survey of 1987 estimated 3,459 fishing crafts on lakes Kyoga and Kwania (Marriot et al., 1988) which increased to 4,045 fishing crafts in 1991 and 6,501 fishing crafts in 1997. The recent and most comprehensive Frame survey in 2002 showed a slight decline to 6,462 fishing crafts. The number of landing sites on lakes Kyoga and Kwania increased from 266 in 1997 to 289 in 2002. There has been some shift in the gear usage e.g. the number of fishing crafts using gill nets have been declining from 2,924 in 1991 to 2,567 in 1997 and 1,647 in 2002. Conversely the number of crafts using beachlboat seines increased from approximately 180 in 1991 and 885 in 1997 to 983 in 2002. Such increases in numbers of destructive fishing gears and overall fishing effort is among the factors that contributed to the decline in fish catches after initial increases that were due to the introduced L. niloticus and O. ni/oticus.

The recent Catch Assessment Survey (CAS) conducted by NAFIRRI in 2006 on lakes Kwania and Kyoga showed similar catch rates of Nile perch of gillnettin~ and beach/boat seining boats in the two lake i.e. 4.9 ± 1.5 and 4.1 ± 1.3 kg boar day" for gillnetting boats and 15.9 ± 7.2 and 18.4 ± 3.6 kg boar1day·1 for beach seining boats in Kwania and Kyoga respectively. The Nile perch long line catches in the

20 1 1 two lakes were low at approximately 2.1 kg boar dai , characteristic of a poor Nile perch fishery. Instead of Nile perch, the long lines seem to be tar~eting Protopterus for which they showed higher catch rates of 8.4 kg boar1day' . The catch rates of Nile tilapia of gillnetting boats, the main gear for the species, were very low in Lake Kwania at 1.94 ± 1.2 kg boar1day·l compared with 17.2 ± 4.8 kg boar1dai1 in Lake Kyoga. Reasonably high catch rates of fresh Mukene of 96.5 ± 25.5 kg boar1day'1 were recorded in Lake Kyoga. Whereas Lake kyoga was visited twice in 2006, Lake Kwania was visited only once during moon phase due to limited resources. As a result there was limited coverage of the Mukene fishery in Lake Kwania. The moon could have also contributed to the low tilapia catches recorded in boats using gil/nets. Based on the limited 2006 CAS of the two lakes, L. niloticus, O. niloticus and R. argentea were the three most dominant fish species in the catches. The estimated annual catches of Kwania were dominated by Nile perch"'(4,999 t) constituting 45% of the catches, followed by Mukene (2,755 t) (25%) and tilapia (1,165 t) (10%) (Table 2). On the other hand, the Lake Kyoga annual catch estimates were dominated by Mukene (15,375 t) (44%) followed by Nile tilapia (9,885 t) (28%) and Nile perch (5,349 t) (15%). The total annual catches of the two lakes was estimated 45,823 t of which Lake Kwania contributed 24% and Kyoga 76%.

Table 2. Estimated Total fish annual catches (tones) in lakes Kwania and Kyoga in 2006 I I I L. O. R. Haploch- I B. l P. C. Other Lake niloticus niloticus araentea romines I docmak I aethioDicus narieninus spp Total

Kwania 4,999 1,165 2,755 249 28 I 918 268 728 11,109 rKYOya 5,349 9,885 15,375 1,381 2~-I 516 I 261 34,714 I Total 10,347 11,050 18,130 1,630 30 2,864 784 )989 45,823

The catches in Lake Kwania contained several fish species which were not recorded in the catches in Lake Kyoga that included Mormyrus kannume, Schilbe intermedius, M. macrocephalus, Gnathonemus longibarbis and Mercusenius graham. This is evidence of higher fish species diversity in Lake Kwania compared with Lake Kyoga.

The fisheries of Kyoga small lakes

A recent inventory of the satellite lakes in the Kyoga basin in March 2007 has revealed that several lakes have not been studied and little is known about their fish stocks. Some of these lakes harbour species which have been lost from the larger lakes in the basin, i.e. Kyoga and Kwania. In 2004 for example there was a request by the Han. Minister of State for Fisheries for a scientific investigation of the Lake Kyoga basin lakes within the boundaries of Pallisa district. There was also a related request for restocking of tributaries of Lake Kyoga in Pallisa with big-sized fish. In addition, there were concerns that Lake Bisina was 'dead' due to

21 extensive weed infestation and low fish catches. In other Kyoga small lakes e:g. Kawi, Gigati, Lemwa, Adois, Nakuwa, Pochoto, Kiondo, Naragaga, Kodiko, despite diverse fish species the general commercial fisheries were not productive. In Other lakes e.g. Nabisojjo and Kimira, the fisheries are healthy and only require management measures to be put in place. Unfortunately, most of these accounts are not supported by evidence of recorded fisheries information.

Some of the Kyoga small fakes are Ramsar sites dedicated for conservation e.g. Lake Bisina, L. Opeta, and L. Nakuwa while others like Lake Gigati have been designated as biodiversity conservation areas. Some Kyoga small lakes are seasonal, e.g. Semere, Adwara, Amoka, Adwara-Ateku, Aibapet, Kokongo, Geme, Atirwai and may.. not be considered for any further investigations. Lake Bisina In November 2004, NAFIRRI conducted a limited Catch Assessment Survey in the Kumi district part of L. Bisina. Only two fishing gears, gillnets and long line hooks were encountered during the CAS. The mean fish catch rate of gillnetting boats 1 1 was 2.6 ± 1.0 kg boar dai , which was composed of C. gariepinnus (30.0%), O. niloticus (25.3%), O. variabilis (10.7%), B. docmak (9.6%) and S. victoriae (7.3%), Haplochromines (6.8%), T zilli (4.6%), P. aethiopicus (3.0%), 0. leucostictus (1.8%) and O. esculentus (09%). The long lining boats made better catch rates 1 1 than gillnetting boats of 5.4 ± 2.1 kg boar dai , composed of two fish species P. aethiopicus (94.2%) and C. gariepinus (5.8%). Overall for both fishing gears, the dominant species in the catch were P. aethiopicus (73.6%), Clarias gariepinnus (11.2%), O. niloticus (5.9%), O. variabilis (2.4%) and B. docmak (2.1 %). The Nile perch was completely absent from the catches despite the lake having supported an important Nile perch fishery in the 19805, which has since collapsed.

Lake Nakuwa Frame and catch assessment surveys were carried out in Lake Nakuwa by NAFIRRI in September 2006. Like in Lake Bisina, the CAS team come across only two fishing gears, i.e. gillnets and long line hooks. The overall catch rate of gillnetting boats was 6.1 kg boar1dai1 composed of O. niloticus (47.2%), L. niloticus (32.3%), P. aethiopicus (11 %), C. gariepinnus (8.3%). The other fish species which were caught by gillnetting boats in small quantities included M. kannume, O. leucostictus, S. victoriae and haplochromines. The overall catch rate of long line hooks was 5.5 kg boar1dai1 mainly composed of C. garipinnus (49.4%) and P. aethiopicus (47%) Estimates of total annual yield were 484.1 t (Table.. ).

22 Table 3. Estimates of total annual catches (tonnes) in Lake Nakuwa in 2006

~Gilln~--t.:Ong line \ I catches catches TOTAL L. niloticus 151.1 - 151.1 ---on/loticus 220.7 1.0 221.7 Haplochromines 0.1 - 0.1 P. aethiopicus 46.0 13.1 59.1 C. qariepinus 33.1 13.8 46.9 M. kannume 0.6 - 0.6 o .Ieucostictus 3.4 - 3.4 S. victoriae 1.3 - 1.3 TOTAL 456.3 27.9 84.!..J

Pallisa minor lakes A rapid socio-economic evaluation of the fisheries of three Pallisa lakes (Komunuo; Nyasala and Meito) was carried out in November 2004 through which key informants identified P. aethiopicus and Tilapia as most important commodities (Table 4).

Table 4. Estimated fishery characteristics of three Kyoga basin lakes in Pallisa.

Lake No Types of No. Types No. Fish Est. catch I fishers boats boats of gear gears species (kg/day) Komuno 40 Parachute 15 Gillnet 100 Tilapia 200 Dugout 5 Hook 500 Protopferus 500

Nyasala 90 Parachute 30 I Gillnet 500 Tilapia 700 Duqout 10 Hook 2000 Protopterus 700

Meito 35 Parachute I 12 Gillnet 200 Tilapia 300

I ' Hook 9QQJProtopterus 400 -- I I

Synopsis

The foregoing review recognizes considerable knowledge gaps on the fisheries of the small Kyoga basin lakes. The recent field inventory of the satellite lakes in the Kyoga basin in March 2007 identified some lakes, namely Owepet, Awoja, Pochoto, Naragaga, Adois Gawa, Amunuo, Lemwa, Kawi, Gigati, Nyasala to be considered for detailed study to identify candidates for fish stock enhancement. A rapid survey to generate information on the fish species landed; estimate the fish catch rates, fishing effort predict annual production of these systems as well as the gathering of community information on fish catch trends and their views on stock enhancement should be implemented.

23 5. Environment Factors in the Kyoga Basin lakes

Executive summary

Kyoga basin lakes consist of two major lakes (Kyoga and Kwania), two medium sized lakes (Bisina and Nakuwa) and over 30 small lakes. The water environment of these lakes is the least known aspect of these production systems. This is because of lack of information//data on their environmental status. Available information, though scanty, mainly covers Lake Kyoga and Kwania with a few small lakes. It is surprising that though a number of projects (e.g. Agricultural

Development Project of the 1980s, the Nile Perch Project of the 1990s and LVEMP I of I~ 1990 to early 2005) addressed fisheries issues of some Kyoga basin lakes, the status of the environment was taken for granted.

Consolidated environmental data on some Kyoga basin lakes was generated recently under funding from ARTP II. From these interventions the following was' noted: 1. Data, though available for some Kyoga basin lakes, is inconsistent and does not reflect seasonality; 2. Data/information on the status of the environment is available for a few lakes e.g. of the eleven lakes identified for further investigation, only three (Lemwa, Kawi and Gigati) have some data collected with funding from ARTP II; 3. Available information is "grey literature" Le. is not published. Some data is only available in raw form 4. Some lakes e.g. Bisina, Agu and Nyaguo, have relatively low abundance and diversity of invertebrates. This is an important finding because invertebrates especially zooplankton and early life stages of zoobenthos and critical foods for early stages of all fishes. 5. The issue of aquatic weeds needs to be addressed since most small Kyoga basin lakes have extensive and dense cover of the plants. The case at hand is infestation by submerged weeds especially Najas horrida, Ceratophyllum demersum, Hydrilla verlicilata, Utricularia spp, and others that impair fish harvesting using gill nets.

Given the above scenario, it becomes apparent that the status of the water environment of candidate lakes be established in order to rationally zero down to those that can support restocked fish.

Introduction

The Kyoga basin lakes are situated between longitude 32°05' - 33°35'E and latitude 01°05' - 01°55'N. They consist of two major lakes (Kyoga and Kwania), two medium sized lakes (Bisina and Nakuwa) and over 30 small lakes (Figure 1). Lake Kwania is relatively narrow and shallow (about 4m), stretching in the northeast-southwest direction, and joins the western extremity of Lake Kyoga to

24 form the/ower Victoria Nile. This array of lakes and associated rivers, streams and wetlands lie in an extensive catchment (- 56,125km2 in area). The total surface 2 area of these lakes is estimated at 2,800 km . These lakes are believed to have been formed when a river valley, possibly the upper reaaches of the Kafu River, was flooded due to backponding and/or spillover from Lake Victoria as a result of tectonic activity. These lakes are surrounded by extensive wetland systems with papyrus (Cyperus papyrus) as the dominant emergent aquatic macrophyte. The main rivers associated with the Kyoga Main Lake include Victoria Nile, Sezibwa, Omunyali and Palacho. Rivers Alango, Akwenyi and Abalang feed Lake Kwania, while River Mpologoma and several seasonal streams feed the small lakes from the eastern and north-eastern parts of the catchment. Most of the catchment particularly in Karamoja, Teso and Nakasongola is a traditional rangeland for rearing of cattle and other livestock. High stock densitres in these areas cause over grazing "thus exposing the catchment soils to various forms of erosion. The above setting poses a potential nutrient and siltation problem for the lakes. While no systematic research has been undertaken to assess this potential environmental problem, it is assumed that the extensive flood plain wetlands along the various streams and rivers act as filters for silt and excess nutrients.

Figure 1: Map showing the location of Kyoga basin lakes and their catchment

25 Lake Kyoga is the largest in the basin (-1,720 km\ with an average depth of 35m. The small lakes lie in the floodplain of the eastern drainage system to the east of the main lake (Twongo 2002). Most of these small lakes seem to have more than one name; and this was attributed to the different ethnic groups of people living in the areas surrounding the lakes (Mbabazi 1999; Aanyu & Nakiyende 2007). This disparity in names was a big constraint especially when locating such lakes using the old maps.

Under the ADB-funded stock enhancement project which is meant to enhance fish production through restocking of some of the Kyoga basin lakes with selected fish species, NAFIRRI has proposed lakes Owapet (Aibapet) in Katakwi, Awoja, Pochoto, Naragaga (Nananga) and Adois (Alos/Nakabale) in Soroti, Gawa/Gawe in Kumi, AmurJ,lo, Lemwa, Kawi and Gigati in Pallisa, and Nyasala in Kamuli for further investigation and likely restocking exercise. Before the restocking programme is implemented, the suitability of some lake has to be ascertained through literature reviews, a process that will help identify information gaps. This will be followed by addressing the information gaps through field data collection. In this way, rational scientific decisions will be made to guide selection of candidate lakes for restocking.

Literature review has been done extensively, and it has been found out that there are major information gaps regarding the status of the water environment for fish production. Important environmental parameters that influence fish production include water quality (pysico-chemical parameters). ambient macro-nutrients, algae (primary production, biomass and species composition), aquatic macrophytes and weeds (diversity, cover abundance and distribution), in addition to zooplankton and macro-invertebrates (abundance, diversity and distribution). Macro-nutrients such as nitrogen, phosphorus and silicica are necessary for algal primary production, a process that yields organic matter principally through photosynthesis. This process is a life-support process for all organisms including those that are aquatic, with fish inclusive. Thus, primary production forms the basis of all food chains/webs.

Chapter 2: The water environment parameters

5.1. Water quality (physico-chemical characteristics)

Historical data on water quality of most Kyoga basin lakes is lacking. Recent surveys funded under ARTP II and Development Budget (GoU) enabled collection of water quality data of some satellite lakes i.e. Agu, Kawi, Gigati, Nyaguo, Lemwa, Nakuwa, Nawampasa and Bisina; this data is the only consolidated set of data and forms the major part of this report (Figure 2.1). Past research efforts e.g. under ADP in the 1980s did not address issues of water quality probably because this project was solely designed with the objective of assessing fish stocks. In addition, some information on water quality of some Kyoga basin lakes has been collected, but little has been published. The data on Lake Kyoga needs detailed

26 processing to make firm interpretations and conclusions. On the whole, the physico-chemistry of Lake Kyoga is quite similar to that in the inshore waters of Lake Victoria. This is probably due to the fact that the largest inflow into Lake Kyoga originates from Lake Victoria via the Victoria Nile. However, Lake Kyoga exhibits considerable spatial variability in physico-chemical characteristics notably water transparency and conductivity, in addition to nutrient chemistry (Mungoma, 1988; FIRI Ann. Rep. 1996/97). These observations probably reflect differences in the drainage (flows) from various parts of the catchment.

Electrical conductivity of surface waters is shown in Figure 2.1 (a). It can be shown that most of these lakes have more elevated water conductance compared to Lakes Victoria and Kyoga whose mean conductivity ranged between 100 and 140 1 IJS cm- . The significantly high water conductance in Cake Gigati could not be easilyexplainl!d

1,000 l

800 ~

2. 600 ~ c

fJ:J 400 1J oC () 200

~ ~~

~~ _Il> ,>0 ~v

*-~~ ~v rg":i"" \"

a ~Q ~-\,,;8 v ef

#'l> ~ Lakes

Figure 2.1 (a) Water conductivity of some Kyoga basin lakes

Most Kyoga basin lakes were relatively well aerated (Figure 2.1 b) hence may be good candidate lakes for restocking if dissolved oxygen was the major determining parameter since minimum concentration was always above 5 mg L- 1 (Ref...). This minimum value is known to be ideal for fish survival. The good dissolved oxygen concentration is largely attributed to presence of aquatic plants, especially the submerged growth form that recharge the system with oxygen through photosynthesis.

27 10

~ "18 --' -OJ E. 6 ~ c:i ci 4

0 ~ (y~

Lakes

Figure 2.1 (b) Surface water Dissolved Oxygen concentration in some Kyoga basin lakes

The warm temperatures of most Kyoga basin lakes may not limit fish survival and growth. Temperatures for some small lakes (Figure 2.1 c) ranged between 26 and 28°C

29 U "--' 28 E! .2 i 27 ~ 25 '124 &'0'?>'"

28 Figure 2.1 (c) Surface water temperature in some Kyoga basin lakes

The pH of most small lakes ranged between circumneutral and slightly alkaline conditions (Figure 2.1 d). This was probably a result of the high buffering capacity for these lakes

6 ~ 4

0 rP ~ r!' d~ ~~ / ~ Lakes

Figure 2.1 (d) Surface water pH in some Kyoga basin lakes

29 Nutrient status of some Kyoga basin lakes

Although some fisheries research activities have been conducted on some Kyoga basin lakes, available documentation indicates that most were done on the Kyoga main lake. The information on nutrient status will therefore focus on the Kyoga main lake, Lake Kwania and a few small lakes

Lake Kyoga-main The study on horizontal differentiation in the limnology of Lake Kyoga (Mungoma 1988) revealed that environmental variables like alkalinity and conductivity were relatively higher and water transparency lower in the east compared to the west of the lake. Concentrations of silica (Si03-Si) and sulphate (S04-S) also decreased towards the we,st whereas nitrate (N03-N) and phosphates (P04-P) were relatively evenly distributed and varied seasonally in the lake. The high alkalinity and conductivity, in addition to concentrations of Si03-Si and S04-S were attributed mostly to dissolved minerals brought into the lake by the eastern drainage; these . minerals get diluted westwards by the inflowing Victoria Nile waters. It was probable that even the distribution and seasonal variation in the concentrations of nitrates (N03-N) and P04.P in the lake were more of natural phenomena as compared to the present elevated levels of such nutrients mainly caused by human activities in the catchment. Recent findings (Magezi et al. 2000, Ndawula at a/., 2001, Twongo 2002) indicated that the water quality of Lake Kyoga was deteriorating as noted from increased algal biomass and dominance by blue-green algae. Such changes were attributed to accelerated loading of nutrients like phosphorus and nitrogen from the catchment. With increasing human population and associated activities in the catchment, such problems are likely to occur hence need for continued monitoring.

Review on fisheries and environment of Kyoga lakes (Twongo 2002) indicated that until recently there was little concern about water quality in the Kyoga basin lakes. Previously there was low human population, minimal fishing pressure and moderate agricultural activities hence minimal and localised disturbance of the natural environment. However, recent findings based mainly on Lake Kyoga indicated a transition from mesotrophic to eutrophic conditions. There were no visible symptoms of deteriorating water quality in Lake Kyoga but fish catches had

declined and concentrations of total phosphorus (TP) and nitrogen (TN) as well as soluble reactive silica (SRSi) in the lake was high. The high TP (46.5 - 155.0 ~g L 3 \ algal biomass (10-150 mg.m- ) and low secchi depth (0.2 - 1.0 m) were manifestations of the eutrophic conditions in the lake. The conditions were tending to excess Phosphorus (P) and deficiency in nitrogen (N) in the lake and this would allow unfavourable change in plankton community as seen in Lake Victoria. Since phytoplankton make up the base of food web, such unfavourable change in their community would definitely pose a negative impact on fish in the lake.

The data in the field activity report following a survey in the eastern part of Lake

Kyoga (FJRRJ 2003) indicated mean ranges of selected nutrients in the lake water

1 1 1

to 39.8 - 118.4 ~g L- TP, 1,11.8 -10,629 ~g L- SRP and 8,737-13,162 ~g L-

30 SRSi. The range for Chl-a was generally low i.e. between 1.39 IJg Lo 1 and 9.04 IJg. 1 L- . The survey in the western part of Lake Kyoga (FIRRI 2004), showed that TP 1 1 was ranging from 236 to 1,086 IJg L- , SRP was between 30 and 489 IJg L- , while 1 Chlorophyll-a concentration ranged between 14.3 and 26.6 IJg L- • In a similar survey in the western and central parts of Kyoga (FIRRI 2006), TP ranged from 87 1 to 317 IJg L-\ SRP between 14 and 27 IJg L- , ammonium (NH 4-N) between 1.0 1 1 1 and 33.0 IJg L- , N02-N from 15 to 17 IJg L- , and N03-N from 29 to 58 IJg L- . Chlorophyll-a concentration ranged from 66 to 266 IJg L- 1 and was relatively higher than in the previous surveys (FIRRI 2003, 2004).

The reports (FIRRI 2003, 2004, 2006) indicated that the nutrient concentrations and phytoplankton status during the mentioned surveys were generally within the intermediate levels of biological productivity and were relatively supportive to fish production. SQme differences in concentrations of the selected nutrients as well as chlorophyll-a, during the mentioned surveys in Lake Kyoga, probably were a result of both temporal and spatial effects within the lake as it was earlier reported (Mungoma 1988).

Although such information on nutrients and other aspects like chlorophyll-a, may be available for Lake Kyoga relative to other Kyoga basin lakes, consistency due to seasonality effects during their collection is poor. The data was collected only during December, May and January of 2003, 2004 and 2006, respectively. This shows that the three surveys were not well spread over the years to reflect seasonality effects, and may not be representative of the conditions that were prevailing in the lake.

Lake Kwania Mean values of selected nutrients in Lake Kwania (NAFIRRI 2006) ranged 1 1 between 27.1 and 68.71Jg L- NH 4-N, 9.2 and 15.91Jg L- N02-N, 23.8 and 34.71Jg 1 1 1 L- N03-N, 83.7 and 133.1 IJg L- TP, and between 111.8 and 10,6291Jg L- SRSi. The range for algal biomass (Chi-a) was between 10.9 and 32.9 IJg L-\ and blue green algae were the dominant taxonomic group. The relatively high algal biomass probably indicated some increased nutrient enrichment in the water column. This algal standing crop in the lake could sustain fishery production. However, data that is being reviewed was collected only once in a year and may hence not be representative of the actual situation for most of the year. Thus, detailed work to assess the nutrient status of the lake during various seasons is required.

The smaller Kyoga basin lakes In the study conducted on trophic structure and diversity of Haplochromines among selected Kyoga basin lakes, emphasis was mainly on fish aspects, and very little, if any, on environmental variables (Mbabazi 1999). The only environmental parameter determined was water depth. Recent studies (Magezi et al., 2000) have reported occurrence of high algal biomass for lakes Lemwa and Kawi relative to Agu and Bisina. Waters of Lakes Agu and Bisina had insignificant algal biomass as was indicated by secchi depth (transparency) that was detected down to the lake bottom of the two lakes (Magezi et al., 2000). High chlorophyll

31 levels in lakes Lemwa and Kawi possibly indicated increased nutrient levels that could have arose from impact of human activities in the catchment, as it was the case for Lake Victoria (Muggide 1992). It is likely that nutrient enrichment from the catchment is occurring in the Kyoga basin lakes since they are in the neighbourhood to Lake Kyoga where such problems have already been reported (Twongo 2002). Apart from influences from the catchment, the nutrients may also be arising from regeneration from within the lake sediments depending on the seasons

Effects arising from dissolved materials that are brought into the eastern part of Lake Kyoga by eastern drainage (Mungoma 19BB), can not be ignored for the small lakes that lie to the east of this main lake. The smaliJakes seem to be prone to such effects-like contamination by nutrients. Although there was ample shore vegetation that would contribute to filtering of most of the contaminants like nutrients in stream waters and runoffs before they enter the small lakes, recent findings (Aanyu and Nakiyende 2007) indicated that the vegetation was being threatened by various human activities e.g. cultivation around lakes Pachoto and Omunuo, harvesting of wetland vegetation in addition to over-grazing. This means that the filtering capacity by the vegetation is reduced hence more contaminants may be entering the small lakes. Environmental impacts arising from these human activities need to be assessed. Identification of the sources of the nutrients, their magnitude and possibly their fate in the lakes would be of relevance for the restocking exercise and subsequent management measures.

The report (NAFIRRI 2006) on physico-chemical water status of Lake Nakuwa indicated that the conditions of the lake appeared to be ideal for growth of aquatic biota, both plants and animals including fish. However, there were signs, though not significant, that the lake was undergoing some adverse environmental changes especially at zones close to fish landings. For example, mean concentration of TP was 100 IJg L-1 at most sites with minimal disturbance compared to 300 IJg L- 1 around Namawa (near a fish landing). Mean TN was generally much greater than TP in the lake waters, with mean TN: TP of 25: 1. Mean concentration of TN ranged from 1,231 IJg L-1 at a river mouth to 3,597 IJg L 1 at Kasekenyi. The uniquely high TN value was 13,411 IJg L"1 at Namawa (near a fish landing). It is probable that increases in nutrient levels as a result of various human activities like animal rearing, waste disposal and poor sanitation, in addition to crop farming, is is being practised around other small lakes as well. A collection of mainly unpublished data from NAFIRRI on nutrients of selected Kyoga small lakes (Table 2.1) from 1998 to 2006, indicate low levels of nutrients in the various lakes e.g. mean values of most nutrients (Table 1) were far below those which were found in Lake Kyoga (FIRRI 2003, 2004, 2006).

32 Table 2.1: Concentrations of nutrients in IJg L- 1 of water (mean ± SE) of selected Kvooa small lakes from 1998 to 2006 NO,-N N03-N NH.-N SRP TOP SRSi Gigati 1998-2000 2.7±1.9 8.2±4.8 151.2±77.6 4.9±1.8 3207±19.9 2592.5±566.9 Kawi 1998-2000 1.7±1.4 16.1±6.5 0.8±0.8 8.1±1.9 45.5±19.9 1079.5±245.6 Lemwa 1998-2001 1.4±1.4 33.2±17.9 157.2±15.2 9.9±6.4 103.3±45.7 1337.8±294A Nakuwa 1999-2006 17.0±9.5 7.9±2.9 46.5±34A 14.3±3.6 53.9±33.7 49188±244.2 Nawampasa 1998-2001 0.02±0.01 4.2±2.1 65.9±27.2 23.1±15.6 1335±62.2 1628.4±3742 Nyauo . 1999-2001 4.1±2.5 22.3±10.8 376.3±2325 4.4±0.9 50.1±23.5 1823.9±328.8 Agu 1999-2000 0.14±0.14 1.9±0.6 22.2±5.7 1.1±OA 43.6±5.5

Although nutrient concentrations seem to be lower in most small lakes (Table 1), other findings (Wetzel 2001) indicate that nutrients can easily be loaded and recycled in such shallow lakes. As a result, factors other than nutrients, such as light availability, frequently regulate both photosynthetic productivity and growth of organisms that depend on that productivity. Thus, the low nutrient levels may not necessarily pose adverse effects to fish production in the Kyoga small lakes. The study on trophic structure and diversity of Haplochromines (Mbabazi 1999), which was conducted at the same period, did not consider relating such nutrient concentrations to lake productivity.

Conclusions on review of nutrients a. Information on nutrients for Lake Kyoga was relatively more than that for Lake Kwania and other Kyoga basin lakes. Thus, most small lakes lacked information on nutrients; b. Though some data on nutrients (1998 to 2006) was available for some small lakes like Gigati, Kawi, Lemwa, Nakuwa, Nawampasa, Nyaguo and Agu, there was no publication made from them Le. grey literature. c. Where data exists, there was no consistency in data collection on nutrients in most of the Kyoga basin lakes.

5.2. Algal primary production, biomass and species composition

Algal primary production

Algal primary productivity for some Kyoga Basin lakes is shown in Figure 2.1. Lakes Nakuwa, Lemwa and Nyaguo had significantly higher productivity compared to Lakes Gigati, Kawi and Nawampasa. Lake Agu was the least productive lake among the lakes studied.

2,400

_~ 2,000 ~ N 'E 1,600 Cl E :; 1,200 ....'> g 800 -ae a.. 400

~'lJ 0~'lJ- ",'lJ- ,:,0

. &C:,'lJ- *-'lJ-~ ,?-C:," q,<$:' ~qf ~Q.'lJ- ~"",qff>

v 1t'1i ~ Lakes

Figure 2.1: Algal primary productivity in some Kyoga Basin Lakes

Algal Biomass Mean algal wet biomass per taxa varied considerably among algal species and among lakes (Table 2.2). Similar to the situation in Lake Victoria, blue green algae constituted a larger proportion of the phytoplankton community in all Kyoga basin lakes assessed although light and nutrient conditions were not limiting to algal growth (FIRI Ann. Rep. 1996/97).

34 Table 2.2. Algal wet-biomass (/lg U-') of genera of major taxonomic groups in some Kyoga Basin lakes

Lake ------+ Gigati Lemwa Nyaguo Kawi Nawampasa Nakuwa Cyanophyta Planktolyngbya 56.49 5.56 19.85 2539 0.02 Microsystis 45.04 2.26 2.52 1.69 4.83 0.00 Cylindrospennopsis 9.80 32.30 3.37 6.40 001 Aphanocapsa 5.23 3.15 2.71 9.58 0.04 0.02 Merismopodia 0.35 0.39 0.86 0.17 Anabaenopsis sp. .29.49 0.00 PseudoanabeaQP sp. 2.02 Chroococcus 2.42 0.20 0.01 Anabeana 1.02 0.00 Coelomoron sp. 0.31 0.15 0.10 Romeria Chlorophyta Oosystis sp. 40.24 0.04 Scenedesmus 0.79 369.05 0.40 0.65 0.02 Pediastrum 2.30 0.12 0.46 0.76 0.07 292 Botryococcus braunii 2.13 Monoraphidium 0.53 0.14 0.11 Stuarastrum sp. 0.40 0.02 0.19 0.03 Ankistrodesmus 0.26 0.29 Cosmarium 0.18 0.01 Crucigenia 056 Tetraedron o11 27754.38 Bacillariophyta Nitzschia acicularis 0.03 0.04 0.06 001 Aulacoseira 8.95 1.14 0.12 Cyclotella sp. 0.09 0.12 0.32 0.08 Stephanodiscus 0.13 0.26 Surrirella sp. 4.36 0.06 Epithemia argus 1.08

Lake Lemwa had significantly higher algal biomass compared to Lakes Gigati, Kawi and Nakuwa. The least algal biomass was found in Lakes Nawampasa, Nyaguo and Agu (Figure 2.2)

35 120

100 I ~ 80 Ol --2 Cll 60 ...!. .c U 40

-LL--.

~ *-(lj~' ~'l> ~'l> "o'l> ,,0 9;"

0,0.,1>· e,(' v: !1> ~4,'l>Cf, 'i"

~~ ~~

v ~1> ~1j

Lakes

Figure 2.2: Algal biomass (Chi-a) in some of the Kyoga Basin Lakes

Algal species composition Available unpublished data indicates that the major algal groups belong to the Cyanophyta (Blue-green algae) and the Chlorophyta (Green algae) (Table 2.3). Other algal types, though rare, included the Bacillariophyta (Diatoms), Euglenophyta, and to a lesser extent, the Cryptophyta. It can be noted that the dominant algal group is the Cyanophyta: this group may not be very palatable to most fish that depend on algae as one of the food sources.

Table 2.3. Numbers of algal species belonging to different taxonomic groups in some Kyoga Basin lakes (Adopted from Unpublished Data).

Lake Gigati Kawi Agu Nyaguo Lemwa Nakuwa Victoria Nile

Taxa ---t Cyanophyta 27 28 14 39 32 23 26 Chlorophyta 15 15 14 20 23 12 22 Bacillariophyta 7 7 2 4 8 4 14 Euglenophyta 1 2 0 2 2 1 2 Pyrrophyta 0 0 0 0 0 0 2 Chrysophyta 0 0 0 0 0 0 1 Cryptophyta 1 1 0 0 0 1 2 Total number of 51 53 30 65 65 41 69 taxa

Detailed systematics of the various algal groups in some Kyoga basin lakes has

36 ,~,~., shown a high diversity of these organisms (Table 2.4). Although a number of algal species may be deemed absent from some lakes, detailed data collection may be required to enable generation of sound scientific conclusions.

Table 2.4: Algal species composition in some Kyoga Basin Lakes (p =present, blank cell means absent). Taxa/Lakes Agu Kawi Gigat Nyaguo Lemwa Nakuwa Nawampasa Bisina

Cyanobacteria

Merismooedia elaaans D D D D D D Merismooedia tenussima D D D D Merismooedia sop p . p Microsvslis aerUJJinosa P p P P P P P Microsvstis SPP D D Mincerta D D D P M.flosaaue D p P M. wasarbagi p M.viridis p Ipsuedo anabeana p p p p Nostocle spp p Coelespherum spp D D D D D Coelespherum lacustris p Plank/olvngbya tallingi p p p Plank/olyngbya lamnelica p p p p Plank/olvnqbva nvassae p Plank/olyngbya circumerenta p p p p P D Iplank/olvnqbva spp p P P P P P D D Oscillatoria limnelica p p D P P P D P Anabeanopsis p D D P P D D P Anabeana circinalis p D D P Anabeana flasaue p D P Anabaena Ivalina p Aphanocapsa p p p p p Aphanothecae p p p Cylindrospermopsis africana p p p p P Bo/ryococcus braunii p Chrococcus /uraidis p p P D Chrococcus p D D P P P D D Dic/osphaerium D Chlorophyta Chiarella D p Coelastrum re/iculurum D Oosv/is p D D D P S/ichococcus p Ankis/rodesmus si/gera p p p D ,Ankis/rodesmus falac/us p p P D P D D P

37 Taxa/Lakes AQU Kawi GiQat NyaQuo Lemwa JIIakuwa Nawampasa Bisina Scenedesmas sao a 0 0 0 0 0 p Stuarastrum spp 0 0 Tetreadron trigonum p ---l' 0 p p Pediaslrum simp/ex p p p p p p Pediastrum tetras p Cosmarium-'HJP 0 p p p p p Scenedesmas Iquadricauda p p p Scenedesrnas acuminatus p p p p Chodatetla subsa/sa p D Anthrodesmus p p p . D

.Kircharrutla • p 0 P D Monorophidium p ~ ----l' p p Didymocystis lubercu/ata 0 Bacillariophyceae Au/ocosira spp p p 0 0 Au/ocosira nvassae P Cve/otetla SoP p P P P P P P P Nitzchia SDo p P P

p p p Nitzchia aciculialis 0 p ~ Navicu/a SOD P Fraailaria SPD 0 0 Synedra spp p Euglenophyla Trache/omonas armatus p 0 0 Phacus p p p Euqlena Acus p p p Dinoflageletes G/enodinum p- Ceralium hirudinetla 0 Chrysophyla Matlomonas 0 p Rhodomonas p 0 p 0 0 Crv%monas - 0 0 Ch/yamodomonus p P Tolal No of spp 22 22 31 34 40 29 20 34

The phytoplankton community of Lake Kyoga and its small lakes was dominated by Cyanobacteria and Planklolyngbya. However, Microcyslis, Aphanocapsa and Merismopedia were the commonest genera. Aulacoseira (Melosira) appeared in appreciable numbers in the algal community of lakes Kawi, Gigati and Nakuwa.

38 Conclusions on review of algae a. Information on algae for Lake Kyoga was relatively more than that for Lake Kwania and other Kyoga basin lakes. Thus, most small lakes lacked information b. Though some data on algae (1998 to 2006) was available for some small lakes like Gigati, Kawi, Lemwa, Nakuwa, Nawampasa, Nyaguo and Agu, there was no pUblication made from them I.e. grey literature. c. Where data exists, there was no consistency and seasonality for most of the Kyoga basin lakes; d. The dense cover especially by submerged macrophytes negatively affected algal primary production.

5.3. Diversity, cover abundance and distribution of aquatic macrophytes and w~eds Available data on aquatic macrophytes in some Kyoga basin lakes is summarised in Table 2.5. Although data indicated that Lake Nakuwa had the highest diversity (number of different species), it clearly reflects the major gaps due to limited coverage that was dictated by time constraints. For example, Ulricularia spp which is reported absent in Lake Gigati, was found in the same lake in the recent surveys (Wanda el aI, 2006).

Among aquatic weeds, Najas horrida and Hydrilla verticilala were qUite common. Some lakes e.g. Nakuwa and Kyoga-main had the notorious water weed, the water hyacinth. It is likely that due to the wetland continuum, some aquatic weeds may be dispersed as viable propagules (especially seeds) to such connected systems. Invasive weeds notably water hyacinth in lakes Kyoga and Kwania and the proliferation of a native macrophyte Najas horrida in lakes Bisina and Opeta are major constraints to environmental health in some Kyoga basin lakes. Potential long-term problems could arise from eutrophication and siltation if degradation of wetland buffers and bad land use practices, particularly overgrazing, are not controlled. Naja horida is native in Lakes Bisina and Opeta where, for yet unknown factors, the submerged plant has turned prolific and accumulated huge biomass and extensive cover. Fishermen in the two lakes are worried because these weeds negatively affect their fishing activities. NAFIRRI scientists have made brief preliminary surveys but further evaluation is necessary to determine the magnitude of the weed problem before meaningfUl insight into its environmental basis and impacts can be gained.

Floating islands dominated by papyrus constitute another case of a native macrophyte assuming characteristics of a weed. Some of the small lakes such as Nyaguo and Kawi experience this problem on a diurnal basis under the influence of wind. Floating islands on Kyoga lakes are historical. (Worthington (1929) reported them as a common feature of the restricted openwater zone of Lake Kyoga. The heavy rains of early 1960s exacerbated the problem for many years when the raised lake level lifted portions of the shoreline mats. Many of these broke up into floating islands. Eventually the floating islands disintegrated leaving a much larger open water.

39 2 Table 2.5: Average number of a particular species of aquatic macrophytes (Nos m· ) as recorded in various lakes in Uganda (adapted from Kalende, 2004)

Plant Species Iyingo l. l. Nakuwa l. Bisina l. Agu L.Nyaguo l. Gigali l.lemwa l. Kawi Namasagali NawamDasa Aeschnomene elephroxvlon 1 Amelia Sf) 1 2 Azalia pinnala 200 Bridelia micrantha I 1 4 Caldesia reinformis 1 Cera/ophyllum demersum 30 90 20 2 Ceralophvllum submersum 40 40 60 5 Cissampelos mucronala 3 2 Commelina detusa 50 10 30 5 Crassocephalum SP 2 1 Cvperum denudatus 40 10 2 20 50 Cyperus dive 1 Cyperus mundti/ 40 1 1 Cvperus papyrus 10 2 50 1 50 20 1 80 80 CVDerus rotundus 2 Cyperus sp (stolon) 70 CV/J8russp 1 15 2 Dissotis SD 1 Ech/nDchlDapyramidalis 1 Eclipla alba 1 1 Eichomia crassiDes 50 20 Emelia eoceinia 1 Enhydra flacluans 1 40 10 Ficus conqensis 1 Ficus veruculosa , 2 1 1 1 1 1 1 Fimbristv/is complenata 20 Fuerina umbellata 50 30 2 3 Gymtia ibuenis 1 1 20 30 I 20 10 10 Hibiscus diversifolia 10 25 1 40 Hydrilla verticilata 30 Hvgrophvla sp. 2 Impatiens irinaii 2 IDomea cairica 2 Justicia sp. 1 Leersea fJexandra 10 Lemna SD. 5 Lepistemon owriensis 3 Limnonphvlon Dbtus/folia 20

40 Plant Species Iyingo L. L. Nakuwa L. Bisina L.Agu L.Nyaguo L. Gigati L. Lemwa L. Kawi Namasagall Nawampasa LimnoDhvton saaitifolia 20 1 1 2 Lipacamha chinensis Ludwiaia stolonifera 1 1 Lunhuria octavalis 1 1 1 Melanthrea scardens 1 1 Mimosa piara 2 10 Miscanthusvio/acea 50 1 rl< 8 Naias horrida 50 20 Naias sp. 20 Naias testuu 2 Nvmphaea lotus (n) 20 1 20 30 10 Nvmohaea noudian In) 40 10 90 50 20 15 Oldenlomdia bullackii Ottelia scabra 5 Ottelia ulvifolia 30 10 3 10 Phraamites australis 20 2 Pistia stratiotes 1 15 2 20 Pluchea sp. 1 Polvaonum salicifolia 1 1 2 Polvqonum setulosum 1 Potamoaeton richardii 10 10 2 Potamogeton schweiphathi 70 20 2 Pvcreus nitidus 2 20 Rhamphicaroa recurva 2 1 1 2 20 Stchvs sp 2 Suddia saait/ifolia Swertia sp 1 Thelvotens dentata 10 10 10 20 . 2 Tvpha latifolia 70 5 10 20 2 5 Vrelvtrum diaitatum 50 1 1 Utnculana reflexa 2 Utnculana sp. 1 3 2 10 Vallasnena soiralis 10 Vigna caoensis 1 Vossia cusoidata 40 75 Zehnena minutiflora 1 1 2 3 2 5 75 Zehnena scabra 1 Total No. of Spp 22 23 28 27 20 18 9 6 8 .17

41 The heavy EI-Nino rains of 1997/98 displaced a large number of papyrus-dominated islands particularly at the confluence of Lakes Kyoga and Kwania. Some of the displaced islands are believed to have partially blocked the outlet of River Nile. This created serious flooding and displacement of more shoreline papyrus mats due to backponding in the two lakes.

Conclusions on aquatic macrophytes and weeds

a. Available information was so limited even for the Kyoga main lake; b. Though some data on aquatic macrophytes (1998 to 2006) was available for some small lakes like Gigati, Kawi, Lemwa, Nakuwa, Nawampasa, Nyaguo and Agu, there was no publication made from them Le. grey literature. c. Where gata exists, there was no consistency and seasonality for most of the Kyoga basin lakes;

5.4. Past trends and patterns of invertebrates in some Kyoga basin lakes

Aquatic invertebrates comprise micro-invertebrates (zooplankton) and macro invertebrates (zoobenthos). These organisms are key dietary requirements of some commercially important fishes and therefore their natural oscillations are likely to explain fluctuations in fish stocks. In addition, they are ecologically important. Studies on the Lake Kyoga system on environmental factors including invertebrates have been intermittent. Some of these studies include surveys by Lake Victoria Environmental Management Project (LVEMP I) and Agricultural Research and Training Project II (ARTP II). Under LVEMP-1, eight small/satellite lakes in the Kyoga basin area were studied in addition to main lake itself. These were: Lemwa, Kawi, Agu, Nyaguo, Gigati, Nakuwa and Nawampasa and Bisina.

Zooplankton (Micro-invertebrates)

Lakes Kyoga, Gigati and Lemwa recorded zooplankton numerical abundance estimates of more than 500,000 indo m-2 (Figure 2.3). This level of abundance is indicative of a good food environment that is suitable for support of zooplanktivorous fish larvae and pelagic fish communities that characterise both the Kyoga and Victoria fisheries (Ndawula, 1998). Lakes Agu, Bisina and Nyaguo recorded estimates below 150,000 indo m-2 which is considered insufficient to support productive fisheries. Cladoceran density estimates were generally below 5000 indo m-2 indicating a poor community probably due to impacts of fish predation. Copepoda contributed the greatest percentage proportion (56 to 85 %) to total numerical zooplankton abundance in all lakes except Lake Nawampasa where Rotiferan percent contribution was 62 %.

In many of the studied lakes, rolifers contributed less than 24% while Cladocerans contributed rather small proportions of up to 1%. The dominance of the zooplankton community by small-bodied rolifers in Lake Bisina indicates presence of favourable food resource for the fish larvae and juveniles while food limitation may ensue for adult pelagic fishes (LVEMP 1).

42 A mCopepoda .Cladocers, ORolltera. .Other (seml-planklo n) ., B • others ., U04 .,. .., 30 ] o Rotrfera • 100 " '" "" " ~" "'" oCladocera 90 25 roCopepoda § BO ~ x 70 " 20 j, •Q <; .~ 60 '" 0 15 50 ~ ((} E ,',,', 40 n 8 • ·• »>, ,', . 30 ~• , :}~ • 20 0 .~ 0: 10 1 :::;:: ..a:" 0 0 0 .~ 0 , ~ ,!! , , ~ , .~• • • • • .~• •~ • • • Q .. ~ 8' , • Z 0 , • z Jl • ~ ~ •~ Jl ~ ~ ~ ~• ~ • • ffi ... .~ •~ iii OJ ~ •~ E '" ~ E OJ ~ • .. " • z• • z z• • £• z ~ tl z 5 z• :; lakes Lakes

3 2 Figure 2.3 Total zooplanton density (at the top of each bar X 10 ind.m- ) and relative taxa composition, and B) taxa richness in some satellite lakes in Kyoga Basin, LVEMP (1999-2005)

Lake Kyoga recorded the highest number of taxa (28) while Lake Kawi registered the lowest (8). Lakes Agu and Nyaguo recored 10 taxa while Lake Lemwa registered 11. Lakes Bisina, Nakuwa, Nawampasa, Gigati and the Victoria Nile registered between 16 and 26 taxa (Figure 2.3). In all lakes, the Rotifers contributed the highest number of taxa from 8 taxa in Lake Kawi to 22 in Victoria Nile. The highest number (6) of Cladocerans (water fleas) taxa were recorded in Lake Bisina; while 4 were registered in Lake Kyoga and the Victoria Nile. In Lake Nawampasa, three Cladoceran taxa were recored while Lakes Agu, Gigati and Kawi recorded 2 taxa and Lakes Nakuwa, Nawampasa and Nyaguo each recorded 1 taxa. Lake Kyoga registered the highest number of copepod taxa (6) (Table 2.6). Lakes Agu, Bisina, Kawi, Lemwa, Nawampasa and Nyaguo each recored 1 copepod taxa. Lake Nakuwa recored 2 taxa, Lake Gigati, 4 and Victoria Nile, 3. Two taxa: (Chironominae larvae and Ostracoda), were encountered in zooplankton categorised as 'others' in Lakes Kyoga, Bisina and Nakuwa (Figure 2.3 & Table 2.7).

The species composition of major taxonomic groups (Copepoda, Cladocera and Rotifera), their abundances and occurrence are given in Table 2.7. Copepodites and Nauplii larvae, the juvenile forms of Copepods, were many-fold more abundant in all lakes than their adult forms (Table 2.6).

43 Table 2.6: A comparison of occurrence and densities x=<5000, xx =>5000<500,000, and xxx=>500,000 indo m·2 of zooplankton taxa in selected lakes in the Kyoga basin (Adopted from LVEMP 1, 1999-2005)

Taxa/Lakes A.s.u 8isina Gi.!lati Kawi Kl.£S,1lI Lemw/I Nakuw/I Nawam.e.asa Victoria Nile N1!.auo Copepoda Mesocyclops sp x x x Thermocyclops em/ll' X X X ThermocycJops inClsus Thermocyc1ops oblongalvs X Thermocyclops neg/ectus xx x xx xx xx x X X Thermocyclops deciprens 7mpocyckJps fXJf1finms X x X X Tropocyclcps lene/his xx Thermodlaplomus ga/ebO/des XX Cyc/opoid C

Cladocera ao.~mina longlfoslns X X SenorJaphma comula X X X Chydond spp. X X Daphma fumflartzl X Daphma Jumhor!zl('.elm) X DIBphanosoma axeJsum X X X X Eucye/ops spp Moma mlc(ura X X X X XX XX XX XX XX Macrolhrix sp X XX X X Rotitefa Asplanch,7/1 spp X X XX X X X fjriJctllonus angu{ads X X XX X XX XX XX XX xx X Brach/onus bldentalus X X X X Brach/onus budapeslinenSIS XX XX Brae/Honus quadndenlalus X X Bracfllonus ca1yclflorus X X XX X X X X X Brachlonus caudalus X X X X Bracfllonus dlmidlatus XX X X Braeh,onus falea/us X X XX XX XX XX XX X Brachionus forlicula Braeh!Onus patulus X Brach/onus urr.;eolarrs X X Brach!Onus sp Euclams sp X X FiJinia long/sela X X X XX X X X Film,a opoliens/s X XX X XX X Hexa/flra X XX X XX X Keratella cochleans X X Kerate/la tropica X X XX X XX XX X XX XX X I...ec8ITe Dulfa X XX X X XX XX XX XX X X Platyas quadneomls PoJyartf1ra sp X XX X PolyarlJ1ra 'Vuloans X XX XX Syncflaeta peetinata X Synchaeta sp X X XX XX X XX XX XX X Tnchocerr.;a cylmanca X XX X XX X X Tncflocen;<:t sp X XX X Others (semi-plankton): Chifonomidae larvae X X Ostracoda X

Macro-invertebrate Communities

Abundance of macro-invertebrates in Lakes Kyoga, Nawampasa, Nakuwa, Lemwa, Kawi and Nyaguo were more than 2,000 indo m· 2 (Figuren 2.4). These abundance estimates are comparable to those observed in Lake Victoria. However, in Lakes Agu 2 and Bisina, the abundances were less than 500 ind.m· . This implies that benthic macro invertebrates in Lakes Agu and Bisina are poorly developed and may not be able to support fishery production to an extent comparable to other lakes. Diptera (larvae of lake flies) was the dominant taxanomic group. Gastropoda (aquatic snails) were recorded in

44 all lakes at densities that varied from 37 indo m·2 in Lake Gigati to 832 indo ·m· 2 i.n Lake Nakuwa. Snail densities in Lakes Lemwa, Nyaguo, Agu and Bisina were between 91 and 166 indo m·2 and those for Lakes Kyoga and Nawampasa registered between 356 2 and 506 indo m· .

A OOGastropoda DPelecypoda 8 Ephemerptera .Odonata • Hemiptera CColeoptera mOiptera E1Trichoptera EJHirudinae 1II0ligochaeta ~Ostracoda 8117 2552 9046 7836 3836 1125 2329 423 430 25 III Benthic *100 ~ EI W1acrophyte-associated 90 20 ~ 80 :~~ ~ 70 0;" a. ~" :n"' 15 :~. E 60 c :~~ .c ~r 8 50 .12 :~~ ~:: .j. ~~ ;;; 10 ~~. :n ~ 40 + II II -'" 30 1;j .;.. :~t ~~ I- 5 JI ~ 20 it ;~ .!!! &1 10 ~. Ji :j 11 o o J Ii {, ~z 0 0 .~ ~ => .~ ~ => c '" '" ,.'" 0> '" '" '" '" .!2' 0> '" '"a. => E .'" " :f .!Il a."' => E :e :Yi -'" '" C9 >

Figure 2.4: Total benthic macro-invertebrate density as indiv.m·2 (at the top of each bar) and relative taxa composition, and B) taxa richness in some satellite lakes in Kyoga Basin (Adopted from LVEMP 1999·2005)

Bivalves were recorded in four lakes i.e. Kyoga, Nakuwa. Nyaguo and Agu where densities were very low and varied from 4 indo m·2 in Lake Ky09a to 19 indo m·2 in Lake Agu. Bivalves were not encountered in Lakes Nawampasa, Lemwa, Gigati, Kawi and Bisina. It was noted that the bivalve community in the Kyoga basin area is much less diverse and abundant than the case in the Victoria basin. This may have implications with respect to ecological functions and biodiversity values of the two systems.

Ephemeroptera (Mayfly nymphs) were not encountered in Lakes Bisina. Agu and Gigati. They were recorded in Lakes Kyoga. Nawampasa, Nakuwa, Nya~uo. Kawi and Lemwa. Highest densities were recorded in Lake Lemwa (2176 indo m') and lowest in Lake 2 Nakuwa (85 indo m· ).

Odonata (dragon and damsel fly nymphs) were recorded in all lakes except Lake Gigati 2 with the highest density in Lake Nyaguo (247 indo m· ) and lowest in Lake Bisina (2 indo m..2)

Hemiptera (water bugs) were not recorded in Lakes Bisina, Agu and Nyaguo. However, 2 the highest density occurred in Lake Lemwa (208 indo m· ) and the lowest in Lake Gigati

45 2 ( 5 indo m- ).

No Coleoptera (aquatic beetles) was recorded in Lakes Agu and Nyaguo. The highest 2 2 density occurred in Lake Kawi (501 indo m- ) and the lowest in Lake Bisina (18 indo m- ). The freshwater prawn, Caridina nilotica was recorded only in three lakes, Kyoga, 2 Nawampasa and Nakuwa, albeit at low densities (16 to 77 indo m- ). Occurrence of this group spells the potential of these systems to support the Nile perch whose food requirements in Lake Victoria has been observed to rely to a great extent on Caridina. Such considerations are important for a stocking exercise that is being envisaged.

2 Diptera occurred in all lakes with hi~hest density in Lake Lemwa (5,065 indo m- ) and the lowest in Lake Bisina (244 indo m-). Diptera constitute key fish food organisms for a number of fish species (Corbet 1961; Greenwood 1966). Therefore the systems that support rich communities of this group are considered favourable for the proposed fish stocking exercise.

Lake Kyoga recorded the highest number of taxa (23) of macro-invertebrates, followed by Lake Nakuwa with 12 taxa (Figure 2.4 & Table 2.8). The other lakes recorded between 3 and 8 taxa.

Two of the LVEMP-studied lakes have been designated RAMSAR conservation sites. They are Nakuwa and Bisina. In addition to these two, Lake Opeta is yet another RAMSAR conservation site.

, Table 2.8 A comparison of occurrence and densities (at densities X= <:150, XX= >150<:500. 2 and XXX = >500 indo m· ) of macro-invertebrates taxa in selected lakes in the Kyoga basin, LVEMP 1, 1999-2005.

Taxa/lakes Kyoga Nswampasa Hakuwa lemwa Kawl Gigati NyaguQ Agu Bisina Gastropoda Bel/amya sp. xx X X Biomphalaria sp. XX XXX XXX X X X X Bulinus sp. XXX X XX X XX X Gabia sp. x X X Lymnaea sp. X X Melanoides sp. x X X X X XX Pila sp X X Pelecypoda Byssanodonta sp. X Gorbicula sp. x X X X Mulera sp. X X X X Ephemeroptera • Caenis sp. XXX X X XXX XX PoviIJa adusta X XX X XXX X XXX Odonata Gomphidae X X Libellulidae X X X X X XX X X Coenagrionidae X X X X X Hemiptera Corixidae X X Naucoridae X X X XX X X Ranatura X X Dlptera Chironominae XXX XXX XXX xxx XXX XX XX X XX Tanypodinae X X X XX X X XX XX X Palpomyia sp. X X X X X X Chaoborus sp. XX X XX XX X X X X X Others Trichoptera X X X Coleoptera XX XX XX X XX XX X Arachinida X X Ostracoda XXX XXX XXX Conchostraca X X X Hirudinae XX X XX XX X X Otigochaeta X X X X X XX X X Caridina nifotica X X X Hydracarina X X XX X X Tabanidae X X

In November 2004, an ARTP II-funded survey was conducted on Lake Bisina. This survey, as well as LVEMP I (1999-2005) do confirm that the macro-invertebrate community in Lake Bisina is poorly developed and thus not adequate as a source of food for fishery production. A similar situation was observed for Lakes Agu and Bisina during LVEMP I surveys where zooplanktonic small-bodied rotifers were dominant by diversity and abundance. Compared to other Kyoga basin lakes, the copepod community in Lakes Agu and Bisina was also poor in terms of abundance and diversity. This means that whereas the fish larvae are endowed with suitable food resource, the adult or growing fish could be limited by food resources (Annual Report 2004). Primary productivity was also noted to be very low compared to other Kyoga Lakes

In January and May 2006, ARTP II-funded surveys were conducted on Lakes Kyoga and Kwania respectively. Zooplankton community composition in Lake Kyoga compared

47 well with past records and with that observed in Lake Victoria and the Victoria Nile. The zooplankton composition, distribution and abundance patterns (255,456- 1,152,484 2 indiv. m- ) observed in Kwania compared favourably with the community in Lake Kyoga probably because the two lakes share a common basin area and are geographically linked by the upper Victoria Nile.

Density estimate data generally imply sufficient quantities of zooplankton that can support fishes that depend on zooplankton as a food base i.e. larval fishes and pelagic fish communities especially Mukene (Rasrineobola argentea). However domination of zooplankton communities by small-bodied rotifers is a feature that has been associated

with conditions of eutrophication (high nutrient content). Therefore further nutrient

enrichment, coupled with the apparent high planktivory is lik~ly to result in further loss of the ecologically~more valuable, large-bodied crustacean species of copepods and cladocerans, which may in future reduce economic returns from the fisheries of Lake Kyoga. Similarly, macro-invertebrates total abundance estimate was conspicuously high .and thus it too suggests fish production may be potentially high. With regard to the high abundances of the red midge larvae in sediment, this is an indication of deteriorating water conditions that may not be good (Sekiranda et. al. 2004) for fishery production. Conclusion a. Invertebrate community in Lakes Kyoga, Nakuwa, Nawampasa, Gigati and Kwania occurred in high abundance and species richness. Therefore as key forage items for fishes, they have high potential that can support a fish restocking program in these lakes; b. The invertebrate community was poor in terms of diversity and abundance in Lakes Bisina and Agu and to a lesser extent Lake Nyaguo. The low abundance of the invertebrates in these lakes is inadequate to sustain productivity of fish populations. This implies that if these lakes are to be stocked with fish, the productivity levels at the primary and secondary levels too have to be bolstered as well in order to provide sufficient food base to support the fish stocks.

General conclusion Data on environmental factors such as nutrient loads, natural fish food productivity i.e. algae, invertebrates etc of the Kyoga basin system is very limited but gives the baseline information on lake productivity. The available data is only on 9 lakes out of 54 in the basin. This data is inconsistent and non-seasonal due to intermittent and irregular monitoring.

48 · 6. Socio-economic factors in the fisheries of the Kyoga basin lakes

Introduction

The government of Uganda obtained a loan from African development bank (ADB) to finance a fisheries development project. The overall project goal is to foster economic growth and reduction of poverty, especially among the communities of the Victoria, Kyoga, Albert, Edward and George basin lakes.

To accomplish this, the project intends to use part of the funds to carry out a study to assess the feasibility and establish the modalities for stocJl. enhancement of the Lake Kyoga basin lakes. Enhancement is any activity aimed at supplementing or sustaining the recruitment, or improving the survival and growth of one or more aquatic organisms, or at raising the total production or the production of selected elements of the fishery beyond a level that is sustainable by natural processes.

The purpose of the review is to identify what is known about Kyoga basin lakes in terms of stocks, bio diversity (past status) as well as other socio-economic related issues and identify gaps.

Background

Lake Kyoga is part of the Kyoga lake complex which includes a set of lakes and numerous wetlands in central Uganda. Kyoga lake complex comprises of two major water bodies (lake Kyoga and Lake Kwania) and two medium sized minor lakes (Bisina and Nakuwa) which are 141 and 73 km 2 respectively) and about 50 other small lakes. This array of lakes and associated rivers, streams and wetlands lie in an extensive catchment of about 57,600km 2 (National Biomass Survey, 1999) shared by at least 23 districts in central, eastern and northern Uganda. In this review, the major and small lakes in the Kyoga catchment are collectively referred to as Kyoga lakes.

Twongo et. al (2000) studied the fisheries and environment of Kyoga lakes and reported that Kyoga lakes were formed when a river valley, possibly the upper reaches of the Kafu River was flooded due to back-ponding or spill-over from Lake Victoria as a result of tectonic activity. This process gave rise to the two larger lakes namely Kyoga and Kwania plus a series of small lakes in Pallisa, Kumi and Katakwi districts. The lakes are surrounded by extensive wetlands fed and drained by a complex network of streams and rivers.

The fisheries of Lake Kyoga like that of many other inland waters had developed mainly as a subsistence occupation; and it was only recently that commercialization started. However as a result of the increasing pressure on the lake basin, increased demand for fish as well as other factors, this has led to over exploitation of major commercial species including the indigenous species. Oguttu Ohwayo, (1994) reported that the decline in stocks of major commercial fish

49 species in the Kyoga basin lakes is attributed to many factors including the massive inflow of illegal fishing gears. More so, the fish stocks in the Kyoga basin lakes became vulnerable to exploitation with the gradual decline in the water level at the same time.

The subject of sustaining fish stocks in major and small water bodies need more attention in recent years, with consideration given to stock enhancement to foster economic growth and reduction of poverty.

Significance of the Lake Kyoga basin lakes

Lubulwa, (2003) reported that Kyoga small lakes offer some of the greatest potential for increased fish production. In the past, they were not fully el

The native species in the Kyoga basin lakes have considerably declined and in some cases disappeared due to; the introduction of exotic species especially Nile perch, over exploitation and environmental degradation. However, some of these fishes depleted from larger lakes have been observed to survive in some of the small lakes in the Victoria and Kyoga lake basin (Oguttu-Ohwayo et. a/1998). Despite the socio-economic importance and uniqueness of these lakes, modest research has been carried out on the socia-economic issues.

Kyoga lakes constitute the most accessible and hence vital aquatic resources for the riparian districts. The fisheries resources of the Kyoga basin lakes comprised of 46 species, (Greenwood, 1966) not until they were over shadowed by the introduced species particularly Nile perch and Nile til apia in the late 1970's. These native species supported important fisheries in the larger Kyoga lakes then. However, the boom was short lived and fish catches steadily declined in the 1990's (Twongo, 2002).

The resultant increase in fishing activity and other ancillary socio-economic ventures, though not well documented, are still fresh in the memories of fisher folk and native communities around Kyoga lakes. The fisheries of Kyoga basin lakes are also of greater socio-economic significance in that many communities around receive most of their animal proteins from fish and to some them it is the source of income/livelihood.

Marriott et. aI, (1989) noted that the communities at the landing sites in south Lake Kyoga are largely unsettled, lacking even very basic amenities and are generally described as a small scale fishing industry community. The general way of life of the fishing society as evidenced at many of the landing is also particularly exploitative, with the largest non-fishery occupation being with semi-normadism of the ordinary fisherman's life. This creates the impression of a very transitory society, lacking the permanence of a peasant farming community.

50 Rationale for Socio-Economics review/consideration

During the last two decades a number of ecological changes have been observed in the lake, warranting socio-economics research which is gaining fast pace. The fisheries of Kyoga basin lakes have undergone substantial changes in recent years owing; in particular, to the integrated lake management approach (DFR, 2001).

However, insufficient research has been carried out on Kyoga basin lakes fisheries of particular interest would be the relationships between the lake's biodiversity and socio economic studies, which is still wanting. The great pressure placed on the lake's resources by the heavy populations around the lakes calls for investigations on the coping strategies of the riparian communities and conservation plans for the future. Although stocking has been practiced in many countries in the region, its viaoility, cost-effectiveness and impacts on ruraltommunities have been rarely evaluated.

Impact of introduced species in Kyoga lakes

Early studies conducted (Worthington, 1929) on the Kyoga lakes mainly focused on its environment and catch rates showed a stable lake environment and catch rates. However, in the recent past, studies on fish biodiversity (Oguttu Ohwayo, 1990) have showed that there has been a drastic negative change especially on native species largely attributed to the introduction of the Nile perch and Nile Tilapia. Stocks of most indigenous species in Lakes Kyoga and Kwania declined considerably while some virtually disappeared by the late 1970's.

The small lakes where Nile perch did not have access remained reservoirs for the indigenous fish species. Indeed the decline in fish stocks was a major cause for concern to the riparian fisher communities and to fishery managers in Uganda. This concern was aggravated by the appearance of the invasive water hyacinth (Eichhornia crassipwes), in Lakes Kyoga and Kwania and Victoria in the late 1980's, the socio-economic and ecological impacts due to the weed were severe (Twongo, 2000).

Nsimbe & Akankwasa, (2002) reported that when Nile perch was introduced into Lake Kyoga, major changes took place, with increasing yields from around 18,000mt in 1965 to 167,000mt in 1978. After having a lucrative fishery for about 13 years, total fishery yield declined to about 55,000mt by 1989. During this period the yield of Nile perch dropped from 71,OOOmt recorded in 1978 to 15,000mt in 1989, and during the period of late 1970's and mid 1980's the excess demand for the fish coupled with the general lack of fishing gear and the near collapse of the fisheries administration, led to the wide spread use of illegal fishing gears and fishing practices.

The decline of the Nile perch fishery has been attributed to the use of small mesh gill nets and seine nets which have been rampant on the Lake and the massive inflow of fishing gears in the early 1980's (Ogutu-Ohwayo, 1994). The above scenarios led to the over exploitation of the major fisheries of the lake and Nile perch stocks were affected. The fish stocks in the lake became vulnerable to exploitation with the gradual decline in the water level at the same time.

51 Kamanyi and Okaronon, (2002) examined the fisheries management concerns while combining the socio-economic aspects, aims and views of different groups operating on Lake Kyoga which are important for managerial decision making and noted that the major species targeted were, Tilapias, Nile perch that were fished using Gillnets and Hooks of various sizes. A close examination of the laws related to fisheries management (Kamanyi, 1995) indicated that they were not sufficient enough to ensure management of the fishery sector. Studies conducted on the impact of these gears and methods on the major and some minor lakes in Uganda (Kamanyi, 1996) identified destructive fishing gears, gear sizes and fishing methods. Furthermore, activities of the fishers among other factors in fishery exploitation have led to the decline and in some instances near collapse of some of the fisheries in some of the major and minor Lakes (Odongkara, 1997). ... Fisheries Technologies on Livelihoods

Produced technologies for efficient resource utilization always have impacts on the livelihoods of-people who use them. This impact will either be positive or negative. The surveys on Lake Kyoga provide information on the impact of selected fisheries technologies on the livelihoods of fishers upon which appropriate technologies and policy and policy approaches are formulated and implemented.

Odongkara et ai, (2003) reports that in 2002, Government of Uganda introduced a slot size regulation that outlawed harvesting, marketing, processing and consuming of Nile perch that had not attained 50 em (20") in length to protect immature fish. The study also established levels of compliance amongst fishing communities, their perceptions in relation to the regulation and an impact assessment on the operations of artisanal fishers, fish traders and processors. It was confirmed that most fishers and fish traders/processors were aware of the slot size regulation and were satisfied with the recommended mesh size of 5" for gillnets reason being that they caught mature fish and enough fish.

FIRRI, 2006 reported that most fishers were not complying with the regulation having realized decreased catch rates and reduced fishing incomes as a result of the regulation, which had in effect limited the allowable Nile perch catch to the scarce 20" and above. Fishers and fish traders/ processors identified the fisheries staff, politicians, contract staff and investors in fish processing factories as the main persons constraining the effective implementation of the regulation. Kyoga Basin fishers and fish traders/ processors were of the view that the most effective levels of enforcing the regulation were at the beaches, on the lake and at fish processing factories thus relating to the role of BMUs, the fishers and traders/ processors suggested that BMUs should monitor and enforce the regulation, with assistance from the Department of Fisheries.

Input-output Marketing Systems

In order to realize the development goals within the fisheries sector, it is important that this sector continues to access the inputs it requires in a cost effective manner and can also find market for their output. There are several factors that affect the availability,

52 pricing and utilization of fishing inputs as well as outputs.

Odongkara et aI, (2001) reported that fish marketing in Uganda identified a number of issues, including: supply fluctuations, product spoilage, inadequate business knowledge among traders and lack of financial resources. Other highlights of the study were; most people involved in catching fish reported selling to bicycle traders, an indication that the domestic market was small, scattered, with poor transportation network and best served by bicycle traders. Some of the trading assets owned by fisher traders were mainly the mode of transportation, namely bicycles, motorcycles, light and heavy trucks. The quantities as well as values of the assets were modest, reflecting low investment levels in fish trade, a characteristic of artisanal operations. The average weekly quantities of fish traded were also minimal, in line with the low investments.

Other fish trade ltlputs included fuel, ice, wrapping materials and preservatives of which the traders believed fuel and ice were major constraints to their operations. In the process, prices received were so little that they did not reflect resources and effort put into fishing (Kamuturaki 1998). Even at the major landing sites, it was the traders who set the prices. Fish losses were also frequently experienced on the domestic market, fish traders faced competition with processing plants over supply, which reduced their earnings which was aggravated by the low purchasing power among consumers, insufficient information about the market and lack of financial services for their activities were other constraints to traders.

There were risks and uncertainties associated with unavailability of transport, too few customers or too much fish on the market on a particular day while traders often operated under threats and insecurity due to corruption and intimidation by tax collectors, health inspectors and fisheries officials.

A study (FIRRI, 2006) reported that looking at the management of information systems at the landing sites around Kyoga Basin lakes, it was clear that responses from the fishing input suppliers, retail shop dealers and some of the key informants was that they were not fully aware of details like government policy on fish input and its impact, this would necessitate the increased awareness of marketing information amongst the key stakeholders in this activity. Different kinds of traders were involved in fish trading and distribution some of which included, bicycle traders (men), retailers at beaches (women) who specialized in Tilapia fish species, vehicle traders (refrigerated), pick-up traders, middlemen who dealt in Nile perch and a few women were involved in the mukene fish trade. Some of the common fish marketing channels included, a) From a fisher directly to the consumer, b) From a fisher to a processor and later to the consumer, c) From a fisher to the trader then to the factory and finally to the consumer.

Additionally, improved exposure to markets especially the super market chains through trade fairs and sensitization of market managers on the high quality fish export products vis-a-vis increased returns through value addition was another issue raised

Proposals that were seen to help the fishers of Kyoga Basin lakes primarily included;

53 establishing distribution points at landing sites. More respondents expressed the desire of accessing credit facilities to acquire fishing inputs. The other marketing issue raised was the need to provide physical infrastructure like stores, smoking kilns, coolers, fish slabs, weighting scale and fish boxes together with institutional infrastructure like offices and records to ease fish transactions.

Fishers suggested that they should be given the actual equipment on credit and asked to pay up as they produce. A few respondents proposed that government is in a reliable position of assisting them by waiving the taxes levied on fishing inputs, consequently the prices would be reduced to enable people carrying out fishing activities purchase such equipment at reasonable prices.

It was found out that some formal sensitization about government policies that relates to the marketing of fish input supplies should be administered to enable traders operate at optimum levels, bearing in mind what the future of this venture holds. It is further suggested that government should enforce lake wide management measures to reduce on the'illegal fishing there by having a sustainable fishery.

Co-Management

It is reported that in recent years the resources of Lake Kyoga have been under severe pressure due to a variety of economic and ecological factors associated with over fishing and a significant decline in fish species. This report has prompted some socio economic studies in the region, one of which is the current attempt by (Kamanyi and Okaronon, 2002) to analyze and understand the purpose of fisheries management while ensuring production over time from fish stocks, preferably through regulatory and enhancement actions that promote economic and social well being of the fisheries and the industries that depend on the resource.

BMUs have been formed on some of the Uganda lakes to represent the fishing communities in the co-management framework adopted to ensure sustainable management of the fisheries and the development of the lake side communities. However, since their establishment on Lake Kyoga, the constraints faced by BMUs in undertaking their responsibilities, resources required to maintain viable and sustainable institutions and means to acquire them have not been fully understood.

Results of a regional study conducted on Lake Kyoga (FIRRI, 2006) indicate that, the activities most frequently done by BMUs are; resolving disputes, receiving visitors and arresting offenders. Other activities done but with less frequency are; conducting meetings, formulating bylaws, keeping inventories, confiscating illegal gears, prosecuting offenders, planning activities and patrolling fishing grounds.

Furthermore, highlights indicate that BMUs are involved in activities that have high potential for social sustainability. However, activities that are crucial for their financial sustainability are not done frequently and well. In that situation BMUs are not sustainable, although they are viable institutions. For BMUs to be viable and sustainable there is need to build their capacity through provision of relevant skills, equipment,

54 awareness, legal empowerment and access to financial resources. BMUs have various sources of income, including; sale of assets, BMU business, rent of assets, beach land lease, fishing licenses, members' contribution in form of fish and cash, registration fees, government remission, fees on letters of introduction, beach access fees and other (unspecified) income sources.

In overall BMUs in the region had adequate skills for conducting meetings and resolving disputes; manpower and time for all activities but they lacked adequate skills and legal power for operating savings and credit services, collection of revenue and data collection. The most useful indicators for evaluating BMU performance were identified as; the number of meetings held in a year and the number of gears confiscated. Other indicators were; the number of people visiting the beach, number and types of inventories kept by BMU, number of disputes resolved by-BMUs, number of offenders prosecuted, nUrQber of arrests made by BMU and number of by-laws formulated.

Current Policies, Laws and Regulations in Relation to Management of Kyoga Basin Lakes

A Review study (Kamanyi & Namisi, 2002), showed that policies have been put forward to modernize the fishery sector for sustainable exploitation and environment management, this would ensure guaranteed food security, incomes and poverty reduction and other people employed in fishery related activities However, current government policies on fisheries are still in transition especially after the policy of decentralization. The harmonization of necessary policies and practices, institutional arrangements and the legal framework appear to be incomplete. Some of the substantive laws that provide for the regulation of the fisheries are not sufficient to ensure management of the fishery sector. The fisheries Act by current standards is neither comprehensive enough nor flexible enough to provide for proper management and conservation of fisheries, fish habitats and the water environment.

Various economic policies are now in place, leading to the relevant programs of action and providing for their institutional, resource and technological requirements. The most important economic policy currently is poverty eradication, implemented through PEAP and PMA (MFPED 2001). Over the years, policies have been developed in the agricultural sector particularly in the fisheries sub sector and these have had varying impacts on agricultural production and marketing. However, several constraints have hindered the intended goal of these policy objectives.

Impact of Policies

Allison (2003) in a study on policy and livelihoods on Lake Kyoga identified gender barriers in the fisheries sector and highlights that access to income-generating and subsistence opportunities in fishing are strongly gendered. He noted that fishing is largely a man's activity although a few women fish for subsistence in shallow waters from the shore using baskets. There are however many women involved in fishery related activities, from repairing nets to trading and fish processing. In general, women tend to be engaged in less profitable activities with lower entry barriers than men. The

55 study further noted that though the Fisheries Policy strongly support empowerment of women, field work confirmed that many women feel their position has improved over the last decade, it is unlikely that the policy alone will address a pattern of labour market segregation that persists in all fishing communities.

Research in the fisher community around Kyoga Basin lakes, FIRRI, (2006) shows that· policy has not had a positive impact on their activities. Some of the beach communities· expressed concern over the fact that there were disagreements between the BMU and the Local Council executive over the policy controls of fisheries resources. On the whole, the Local Governments activities were not friendly as for example in levying of taxes whose impact on the landing sites in terms of development was not being seen. Fishers around Kyoga Basin lakes hardly knew anything about the policy within the fisheries. Just a iew beach leaders appreciated a few government policies that were related to fish marketing like, a trader should have undergone a health check-up and given a health certificate, a trader must posses a trading license. Boats licenses and market dues amongst others should be met.

The policies have also instigated better fish handling practices at fish factories which buy fish for export, tend to buy clean fish these policies have impacted on the marketing of fish input and outputs by boosting the demand, confidence and trust by the international market of the quality of fish that is being harvested in Uganda. Taxes levied on fish input supplies not only constrained the input supplier, but also affected are the fishermen, fish industries, fish traders and also consumers of the end products.

Policies of Liberalization, Privatization, Investment and probably the trade policy had contributed a lot in expanding the markets and increasing prices of fish. Privatization policy, intended to transfer the ownership of business enterprises from public to private hands for greater efficiency and private sector competitiveness are among the issues that have not fully taken shape in the fishery of Kyoga Basin lakes. The introduction of policies such as fish mongers license, fishing vessel license, fishing permit, marketing permit and fish landing fees was a burden to the fishers who were generally poorer than the boat owners. Because of the increased fish market opportunities, almost all the fish caught is sold for income something that had led to reduced food security, high fish prices charged and has exacerbated the fishing of juvenile fish in area around the Kyoga Basin lakes.

There is clear evidence that fisheries tendering is profitable business and consequently, there is much competition to acquire tender. It is estimated that the annual profit from tendering is abut US$150,OOO on Lake Kyoga. These profits are never re-invested in fisheries management and development. Further more, they result in overcharging resource users, especially the poorest users and undermine efforts to promote sustainable resource management. (Bahiigwa et ai, 2003)

HIV/AIDS in the fisheries sector

HIV/AIDS is a unique problem in the fisheries of the Kyoga Basin lakes, posing a great challenge to fisheries managers, health service providers, development planners and

56 resource users themselves. (FIRRI, 2006) reported that HIV/AIDS formed on average 50% of the related causes of death across all rural livelihood groups, but in fishing communities majority (61 %) confessed having extra-marital affairs which accounted for 57% of the deaths and 27% of the illnesses. This has greatly affected the production of the entire Kyoga Basin lakes fishery. Many fishermen have lost lives or migrated and that there is now a projection of the quantities of fish handled now and previously which has been linked to this epidemic. .

A situation analysis by Ministry of Animal Industry and Fisheries (MAAIF, 2004) support international prevalence rates in the fishing communities that are three times higher than the National average. At macro economic levels, it is estimated that HIV/AIDS has reduced the rate of GDP growth by around 2% points per year against a background or relatively rapid economic growth in the last five years. Fisfteries affected by HIV/AIDS may be becaustl ill health reduces fishing effort to inshore areas of the lake with consequential negative impact on fish recruitment and juveniles (UFD, 2004). Production per day has tremendously decreased. Previously the average quantity of Nile perch landed per day was 39.2 kg per boat, mukene 10 kg and that of Nile tilapia was 82 kg, yet previously the landed catch was 128 kg of Nile perch, 26 kg of Mukene and 180 kg of Nile tilapia.

The main cause of deaths in fishing communities around Kyoga Basin lakes had been attributed to HIV/AIDS related illnesses, Malaria, Syphilis, Cryptosporidial diarrhea and witch craft. Around the Kyoga Basin lakes, (DFID, 2001) reveals that women would receive strategic support through lake management structures and planned activities to effectively reduce poverty. This would include improving access for women to savings and credit schemes and to HIV/AIDS support interventions.

Nutrition and Indigenous Knowledge in the fishery sector

Nutrition relates to processes of growth, maintenance and repair of the living body, which depends upon digestion of food after consumption (MAAIF, 1995). The main types of food stuffs include carbohydrates, proteins, fats, minerals and vitamins. Diet consists of those foods or mixtures consumed in required amounts on a daily basis. Inadequate nutrition in extreme cases can produce a condition known as Kwashiorkor among children- an advanced state of protein deficiency or the more protein-calorie malnutrition known as Marasmus.

Margaret, 2006 reported that the diet among the majority of fishers living around Kyoga Basin lakes was carbohydrate-based with inadequate proteins proportions despite being around the lake basin. As such, there was likelihood that some of the community members may succumb to nutrition related diseases unless intervention measures are put in place sooner than later. Apparently, most of the fish is sold to traders who in turn transport it to distant markets and therefore fish available to local consumers is still inadequate besides the quality of the available plant protein from beans and related legumes was not comparable to animal protein.

It is noted that the available indigenous knowledge was diverse across the food

57 production, preparation and processing spectrum and it seemed to be ethnic-specific and rarely got distorted over distance i.e. by movement of people in search of better opportunities around landing sites of the Kyoga Basin lakes. However, indigenous knowledge was not a preserve of a particular gender and it seemed to have been on from respective mothers. The need to document and preserve them cannot be emphasized.

Knowledge areas and gaps for future research

Resources in the Kyoga basin continue to be over-exploited but limited research work is being conducted to elucidate the problem while suggesting solutions. It is well known that these habitats are still the major refuge for many indigenous species thought to be extinct or threatened. •

This review reveals that many gaps still exist on research regarding the related socio economic aspects in the Kyoga Lakes and its environments.

Activity General socio Issues identified from Gaps economic issues the review Management Fishing gears & Level of compliance, Limited information measures/Technol methods perception and their in respect to the ogies Impacts small lakes Fisheries Lake management Government regulatory Limited information management and enhancement in respect to the interventions in small lakes sustainable Information management of the gathered to be lakes including the role used to inform of the community policy on through BMUs management of the fishery Impact of co management and perceptions of the communities of the operations of BMUs Ecology and the Community Community Knowledge Limited information Environment of awareness of the and information on in respect to the Kyoga basin lakes trends in regard to emergence of the small lakes. the changes in the Invasive weeds, environment changes in Water overtime levels, their causes and impacts on fish stocks and the general livelihood.

58 Activity General socio- Issues identified from Gaps economic issues the review

Livelihoods of the Livelihood Fishing activities Limited information communities activities and including fish in respect to the (socio-economic poverty marketing as main communities status of eradication livelihood activities around minor lakes. communities followed by farming. around Kyoga Fishing activities and Limited gender and basin Lakes) opportunities are sex disaggregation largely gendered.• of information

.. Migration and Communities are of settlement varied ethnic patterns background and largely migratory

Food security Main diet was issues including carbohydrate-based nutrition and fish with inadequate demand proportions of proteins despite being close to lakes.

HIV/AIDS and its HIV/AIDS has greatly impact on affected the production livelihoods of the entire Kyoga basin fishery.

I Health and Generally poor health sanitation and sanitation status of the landina sites Inventory of small Community Size of lake, Background lakes knowledge of the accessibility, information small lakes importance, level of dependence, effects of seasonal change in small lakes

I Views of fishing Perception by the None Need for communities on people and the Information on fish stocking anticipated impact Perceptions on of restocking the extent to which the restocking would enhance/contribute

59 Activity General socio- Issues identified from Gaps

I economic issues the review to people's livelihood (SWOT) Views on I monitoring & management of the lakes after restockinq Fish production Availability of Fish have declined in No knowledge of sufficient fish the major and a few the fish stocks in stocks small lakes particularly other small lakes • Nakuwa, Bisina and Kwania

Conclusion

As the Kyoga Basin lake fisheries decline through among other factors habitat changes that accompany agricultural and land developments and intensifying exploitation, it becomes increasingly important to consider ways and means to sustain the availability of fish to rural populations. One of the main strategies that have been employed in most developing countries to improve lake fish production is the stock enhancement of lake waters, particularly lacustrine water bodies.

The subsequent socio-economic survey will address the information gaps identified as shown in the table above. A rapid appraisal approach will be employed to generate the information.

60 Literature Review

Aanyu M and H. Nakiyende (2007). A Report on the inventory of small lakes of Lake Kyoga basin, 13pp. ADP/ Fishery Survey (1992). Fishery Survey of Kyoga lakes. Agricultural Development Project report for the period April 1990 to November 1991. Allison, E, (2003). DFID LADDER project, Working Paper No. 9 - Linking national fisheries policy to livelihoods on the shores of Lake Kyoga, Uganda. Internet source: hUp:l/www.uea.ac.ukJdev/ODG/ladder/ COWl consulting Engineers and Planners, (2002). Integrated water quality/limnology study for Lake Victoria. LVEMP Project Report. Crul, R., (1995). Limnology and hydrology of Lake Victoria. UNESCO. Studies and reports in hydrology 53, 79 pp. DFID (2001). Integrated Lake Management Project DFR (2004). National strategy for reducing the impact of HIV/AIDS on fishing communities. Eriksson, J. (2004). The Lake Kyoga basin - Environmental Scarcity & Conflicts. Master's Thesis, 10p/15ECTS, Uppsala University, Sweden 44 pp. FIRRI (2000). Management of the Fish stocks, Biodiversity and the Environment of Kyoga Basin Lakes. Proceedings of Stakeholder Workshop on Kyoga Basin th th Lakes. 18 - 20 October 2000 Jinja - Uganda 36pp. FIRRI (2000). Workshop report on the Fisheries research on Lake Nabisojjo - Luwero district. 40 pp. FIRRI (2002:). Technical guidelines for management of fisheries Resources, Biodiversity and Environment of Victoria Basin lakes. Technical document NO.1 FIRRI (2003) Field activity report on water environment of eastern part of Lake Kyoga, 4pp. FIRRI (2004) Field report of survey of the magnitude of aquatic weeds infestation and environmental factors fostering their proliferation on Lake Bisina in Kumi and Katakwi districts, 3pp. FIRRI (2004) Field report on environmental status of Lake Bisina, 2pp. FIRRI (2004) Field report on management of fish stocks and environment of western

61 part of Lake Kyoga,5pp. FIRRI (2006) Field activity report on environmental status of western and central portion of Lake Kyoga, 8pp. FIRRI (2006). Assessing the impact of fisheries technologies on livelihoods. FIRRI (2006). Assessment of marketing systems for Nile perch, Tilapia and Mukene and for the fishing and fish farming inputs. FIRRI (2006). Developing fisheries co-management across the fisheries sector. FIRRI (2006). Prevalence of HIVfAIDS among fisher communities and its impact on fisheries management in fishing communities around Lake Kyoga. FIRRI (2006).The impact of eXisting National and Local government policies on the Production and marketing. Fisheries Research Institute (FIRI), (1997). Annual Report, 1996-97. National Agricultural Research Organisation (NARO). Graham, M. (1929). The Victoria Nyanza and its fisheries. A report of the survey of Lake Victoria 1927 - 1928 and appendices. Crown Agents for colonies, London. 255pp. Greenwood P.H. (1966): The Fisheries of Uganda. The Uganda Society, Kampala (2nd Edition). 131 pp. Hecky, RE., H.A. Bootsma, R.Mugidde and FW.B. Bugenyi. (1996). Phosphorus pumps, Nitrogen Sinks, and Silicon Drains; Plumbing nutrients in the African Great Lakes. In: Limnology, Climatology, and Palaeoclimatology of the East African Lakes. Ed. Johnson & Odada, Gordon & Breach Publisher, 205-224 pp. Kamanyi J.R. (1996). Management strategies for exploitation of Uganda fishery resources. Mimeo graphed report. FIRRI, Jinja. Kamanyi J.R., (1995). "Characterization of the fisheries of the major and minor lakes of Uganda and the socio-economic factors influencing fishery exploitation" Kamanyi J.R.and J.R.Okaronon, (2002). Productivity factors and fish production and their fisheries management concerns. A paper presented at the sensitization seminar on fisheries enforcement 7th- 8th May 2002 at Mukono, ARDC. Kamuturaki .S. (1998): The role of UFFCA in the development and management of the fisheries resources. In FIRI: "Towards sustainable development and management

62 of the fisheries resources of Lakes Victoria and Kyoga: Proceedings of the stakeholder's workshop on: the fisheries of Lake Victoria and Kyoga, 24-25 September,1998. Jinja, Uganda. Kaufman, L., (1992). Catastrophic change in species-rich freshwater ecosystems: the lessons of Lake Victoria. BioScience 42: 846-858. Kazungu, J. M., P. O. J. Bwathondi and J. S. Balirwa. Aquatic Biodiversity of Lake Victoria Basin: Its Conservation and Sustainable use eds. (LVEMP I draft book).

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63 Mbabazi D (1999). The trophic structure and diversity of Haplochromines among the Kyoga small lakes. MSc dissertation, Makerere University, 109pp. Mugidde R (1992) Changes in Phytoplankton primary productivity and biomass in Lake Victoria (Uganda). MSc. Thesis, University of Manitoba, 84pp. Mungoma S., (1988). Horizontal differentiation in the limnology of a tropical river lake (Lake Kyoga, Uganda). Hydrobio. 162: 89-96. Mungoma, S. (1 988). Horizontal differentiation in the limnology of a tropical river, lake (Lake Kyoga - Uganda). Mwebaza-Ndawulp, L., (1998). Distribution and abundance of zooplankton and Rastrineobola argentea (Pisces: Cyprinidae) and their trophic interactions in northern Lake Victoria. East Africa. PhD thess. University Austria. NaFIRRI (2005). Report on the fishery of Lake Kimira. October 2005. 4 pp. NaFIRRI (2006). Field activity report on environmental status of Lake Kwania, 13pp. NaFIRRI (2006). Technical report on environmental status of Lake Nakuwa. Nagayi Kalule J.F. (1999). Population Characteristics of Oreochromis esculentus in Satellite Lakes of the Victoria and Kyoga Basins. M.Sc. Thesis Makerere University. 86 pp. National Biomass Survey (1999). Assessment of the natural biomass resources in Uganda. Ndawula L, T. Twongo and G. Magezi (2001). The role of Lake productivity process in fishery production. In: Proceedings of a training workshop: Towards empowering fisheries Officers to manage the fish stocks, biodiversity and environment of Kyoga basin lakes, at FIRRI. Jinja, pp 19-20. NRSP (Natural Resources Systems Programme), (2001a). A review of existing knOWledge of wetlands on Lake Kyoga basin with a focus on people's livelihoods. FIRRI. technical report. NRSP (Natural Resources Systems Programme). (2001 b). How representative is Lake Kyoga, Uganda in the context of African and other tropical wetlands. FIRRI. Technical Report. Nsimbe-Bulega, E. and Akankwasa A. (2002). The status of the Nile perch fishery and potential for production and marketing of Nile perch value added products in

64 Uganda. A paper prepared for CFC/FAO/COMESA. Odongkara O. K., Kyangwa, M., Wegoye J and A. Nyapendi (2003). Report of the Study of the fish marketing sub-sector and livelihoods in Uganda, FIRRI, Jinja. p 33. Odongkara, O.K. (1997). Fish commodity systems economics (Uganda project Final Draft, FIRRI, Jinja). Ogutu-Ohwayo, R. (1984). Predation by the Nile perch Lates niloticus introduced into Lakes Kyoga (Uganda) and its effects on the population of fish in the lake. M.Sc. Thesis. University of Dar es Salaam, Tanzania 147 pp. Ogutu-Ohwayo, R. (1990). The decline of native fishes of Lake Victoria and Kyoga (East Africa) a~d the impact of introduced species especially the Nile perch, Lates niloticus and the Nile tilapia, Oreochromis niloticus. Env. BioI. Fish 27:81-96 Ogutu-Ohwayo, R. (1994). Adjustment in fish stocks and in Life history characteristics of the Nile perch, Lates niloticus L. in Lake Victoria, Kyoga and Nabugabo. PhD, University of Manisota, Winnipeg. 213p. Ogutu-Ohwayo, R. (1998). Reproductive potential of the Nile perch, Lates niloticus and the establishment of the species in Lakes Kyoga and Victoria (East Africa). Hydrobiologia. 162. 193-200. Ogutu-Ohwayo, R. S.B. Wandera, G. Namulemo and D. Mbabazi (1999). The Role of Satellite Lakes in Conservation of Fish Species Diversity in the Lake Kyoga Basin. Final Report of The Biodiversity Support Program MS83. 20 pp. Population figures from Uganda Bureau of Statistics, "2002 Population and Housing Census". Sekiranda, S.B.K., J. Okot-Okumu, FW.B. Bugenyi, L.M. Ndawula and P. Gandhi 2004. Variation in composition of macro-benthic invertebrates as an indication of water quality status in three bays in Lake Victoria. Ug. J.Agr. Sci. 9:396-411. Stoneman & Rogers, 1970 . Twongo T (2002) The fisheries and environment of Kyoga lakes, A review prepared for

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