Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring No. 5, 6th-9th October 2009

The survey covered by this report was undertaken between 6 th and 9th October 2009 as a follow-up on the during construction surveys of the Bujagali Hydropwer Project (BHPP). In addition to two pre-construction baseline surveys in April 2000 and April 2006, four monitoring surveys have so far been undertaken i.e. in September 2007, April 2008, April 2009 and the present one, in October 2009. The 2009 biannual monitoring surveys were conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: 1. water quality determinants 2. biology and ecology of fishes and food webs 3. fish stock and fish catch including economic aspects of catch and 4. sanitation/vector studies (bilharzias and river blindness)

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring no. 8, 6– 10th April 2011

The result reported were from a monitoring survey no.8 undertaken between 6th and 10th April 2011 during construction period of the Bujagali Hydropwer Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far,durin construction phase of the project, seven monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009,October 2009, April 2010, September 2010 and the present one, in April 2011. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: Water quality determinants Biology and ecology of fishes and food webs Fish stock and fish catch including economic aspects of catch and Sanitation/vector studies (bilharzias and river blindness)

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring no. 10 and reservoir baseline, 23rd – 30th April 2012

The results reported on were from a monitoring survey No. 10 undertaken between 23 rd and 29th April 2012 during construction period of the Bujagali Hydropower Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far, during construction phase of the project, nine monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009, October 2009, April 2010, September 2010, April 2011, September 2011and the present one, in April 2012. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: water quality determinants biology and ecology of fishes and food webs fish stock and fish catch including economic aspects of catch and sanitation/vector studies (bilharzias and river blindness) During this survey, baseline assessment of the above mentioned studies was conducted in the reservoir behind the dam, including studies on algae, zooplankton and benthic macroinvertebrates which had been restrained since April 2008. The findings of baseline assessment of the reservoir are also contained in this report and are compared with those obtained from Transect 1(Upstream) and Transect 2 (Downstream).

Biology, ecology and the fishery of Mukene, Rastrineobola argentea

Food and feeding, condition factor, breeding periods, growth and size at first maturity of a small pelagic cyprinid Rastrineobola argentea (P.) in Lake Victoria are determined. Fishing gears and methods that have been used in the exploitation of the species and could be harmful to the fishery are outlined. Management measures leading to possible sustainable exploitation of the fishery are suggested. Adult R. argentea feed on zooplankton during daytime. Juveniles feed on planktonic early instars of lakefly larvae. Although the species breeds throughout the year, two breeding peaks were observed during the drier months of August and December January. Least breeding was observed in the rainy months of April-May and October November. Fishes from the open water station at Bugaia showed higher numbers of breeding individuals than those from inshore areas. The mean monthly condition factor of fish from Napoleon Gulf confirmed breeding peaks as obtained from the number of fish with ripe gonads. The species showed a mean instantaneous growth rate (K) of 1.75 and attains length infinity (Lx) of 54mm. Females of the species in these waters show a reduced size at maturity as compared to ten years ago when exploitation of the species was at minimal levels. The males have however not changed much.

The role of Yssichromis species (Pisces: Cichlidae) in the trophic ecology and foodwebs of Lake Victoria

Many haplochromine cichlids coexisted in Lake Victoria before the upsurge of Nile perch. The introduction of the Nile perch led to depletion of many haplochromines and other fish species in Lake Victoria. The impact of Nile perch predation on haplochromines differed for different haplochromine trophic groups. Yssichromis fusiformis (G) and Yssichromis laparogramma (G) are among the species that have survived in the lake. Yssichromis spp. was studied with the aim of determining their trophic role, food and feeding habits. Samples were collected from Bugaia, Buvuma channel and Napoleon Gulf in the northern part of Lake Victoria. The food of Yssichromis spp. varied with size of fish. Both Y fusiformis and Y laparogramma fed on Copepods, Cladocerans, Chaoborus and Chironomids. Juvenile Yssichromis spp. fed exclusively on zooplankton comprising Cyclopoid copepods, Calanoid copepods and Cladocera. The relative importance of Chironomid larvae and Calanoid copepods was higher in Bugaia than in Buvuma channel while Cyclopoid copepods and Chironomid pupae were relatively less important in Bugaia. The main food items that Yssichromis spp. fed on in Buvuma channel were Chironomid larvae Cyclopoid copepods, Cladocerans and Calanoid copepods. In Napoleon Gulf, fish caught from commercial fishery of Rastrineobola argentea (P) had fed on Chaoborus and Chironomids. Overall, Yssichromis spp. fed on more zooplankton in Buvuma than in Bugaia. Yssichromis spp. and R. argentea are presently the most abundant zooplanktivores in the northern part of Lake Victoria and are playing an important trophic role as major consumers of zooplankton and insect larvae in the foodweb of the lake ecosystem. Yssichromis spp. are bridging the transfer of energy from the lower to the higher trophic levels as secondary consumers. The fishery is still not contributing to the direct conversion of the primary products, the phytoplankton and detritus that were efficiently utilised by the diverse haplochromine trophic groups that existed before the Nile perch boom.

Trophic interrelationships and food-webs among the fishes in ecosystems of the Victoria and Kyoga lake basin

The Victoria and Kyoga lake basins had a high fish species diversity with many fish species that were found only in these lakes. Two Tilapiines species Oreochromis esculentus and Oreochromis variabilis were the most important commercial species in these lakes and were found nowhere else on earth except in the Victoria and Kyoga lake basins (Graham 1929, Worthington 1929). Lakes Kyoga and Nabugabo also had endemic haplochromine species (Worthington 1929, Trewavas 1933, Greenwood 1965, 1966). As stocks of introduced species increased, stocks of most of the native species declined rapidly or disappeared altogether. The study was carried out on Lakes Victoria and Kyoga, River Nile, some selected satellite lakes from the two basins namely Lakes Mburo, Kachera, Wamala, Kayanja, Kayugi, Nabugabo, Victoria, Victoria nile and River Sio(Victoria lake basin). Lakes Kyoga (Iyingo), Nawampasa, Nakuwa, Gigati, Nyaguo, Agu, Kawi and Lemwa (Kyoga lake basin). Species composillon and relative abundance of fishes were estimated by detennining the overall average total number of each species encountered. A trophic consists of species using the same food category. Shannon-Weaver Index of diversity H (Pielou, 1969) and number of trophic groups, were used to estimate the Trophic diversity of various fish species in the lakes. Food analysis has been done on some fishes in some of the sampled lakes and is still going on, on remaining fishes and in some lakes. Generally fish ingested detritus, Spirulina, Melosira, filamentous algae, Planktolyngbya, Microcysists, Anabaena, Merismopedia, Spirogyra, higher plant material, rotifers, Ostracodes, Chironomid larvae and pupae, Choaborus larvae, Odonata, Povilla, Insect remains, Caridina, fish eggs and fish. Eight trophic groups were identified from thes food items ingestes. These included detritivores, algae eaters, higher plant eaters, zooplanktivores, insectivores, molluscivores, prawn eaters, paedophages and piscivores. Trophic diversity by number of trophic groups was highest in Lake Kyoga (6) followed by lakes Kayugi, Nabugabo, River Nile and Mburo (3) and the lowest number was recorded in kachera (2).

The biology, ecology, population parameters and the fishery of the Nile tilapia, Oreochromis niloticus (L)

Oreochromis niloticus (the Nile tilapia) and three other ti1apine species: Oreochromis leucostictus, Tilapia zi11ii and T. rendallii were introduced into Lakes Victoria, Kyoga and Nabugabo in 1950s and 1960s. The source and foci of the stockings are given by Welcomme (1966) but the origin of the stocked species was Lake Albert. The Nile tilapia was introduced as a management measure to relieve fishing pressure on the endemic tiapiines and, since it grows to a bigger size, to encourage a return to the use of larger mesh gill nets. Ti1apia zillii was introduced to fill a vacant ,niche of macrophytes which could not be utilised' by the other tilapiines. Tilapia rendallii, and possibly T. leucosticutus could been introduced into these lakes accidently as a consquence of one of the species being tried out for aquaculture. The Nile perch and Nile tilapia have since fully established themselves and presently dominate the commercial fisheries of Lakes Victoria and Kyoga. The original fisheries based on the endemic tilapiines O. escu1entus and o. variabilis have collapsed. It is hypothesized that the ecological and limnological changes that are observed in Lakes Victoria and Kyoga are due to a truncation of the original food webs of the two lakes. Under the changed conditions, O. niloticus to be either playing a stabilizing role or fuelling nutrient turnover in the lakes. Other testable hypotheses point to the possible role of predation by the Nile perch, change in regional climate and hydrology in the lake basins.

Fish species diversity, and the biology and ecology of common fish species in Lake Albert

Lake Albert contributes about 10% to the national fish production. It supports a multi-species fishery based on endemic species. To local fishermen, Lake Albert is a lifeline providing food and income.

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring No.7, 4-7th September 2010

The results reported on were from a monitoring survey No.7 undertaken between 4 th and 7th September 2010 during construction period of the Bujagali Hydropower Project (BHPP). Two pre-construction, baseline surveys in April 2000 and April 2006 were conducted and so far, during construction phase of the project, six monitoring surveys have been undertaken i.e. in September 2007, April 2008, April 2009, October 2009, April 2010 and the present one, in September 2010. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: I. water quality determinants 2. biology and ecology of fishes and food webs 3. fish stock and fish catch including economic aspects of catch and 4. sanitation/vector studies (bilharzias and river blindness)

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring no.12, 25th-30th April 2013

Bujagali hydropower dam construction is now completed and a reservoir behind the dam has been created, extending all the way up to Kalange-Makwanzi, an upstream transects. During the 10th monitoring survey-April 2012, a third transect was established in the mid of the reservoir where it runs up to 30 m deep and sampled similarly as at the two original sampling transects, Kalange-Makwanzi and Buyala-Kikubamutwe for comparative purposes. This monitoring survey No. 12 undertaken between 25th and 30th April 2013 is the third one to be conducted after completion of construction of Bujagali Hydropower Dam. Two pre-construction baseline surveys in April 2000 and April 2006 were conducted and during construction phase, eight monitoring surveys (September 2007, April 2008, April 2009, October 2009, April 2010, September 2010, April 2011, September 2011) were conducted. Since 2009 biannual monitoring surveys have been conducted at an upstream and a downstream transect of the BHPP with emphasis on the following aspects: water quality determinants, biology and ecology of fishes and food webs, fish stock and fish catch including economic aspects of catch and sanitation/vector studies (bilharzias and river blindness). In the post-construction monitoring surveys, the assessments of algae, zooplankton and benthic macro-invertebrates which had been restrained since April 2008 were also included.

Aquatic ecology monitoring: water quality, fish, fish catch and parasites: monitoring no.4, 3rd-7th April 2009

The survey covered by this report was undertaken between 3rd and 7th April 2009 as a follow-up on the during construction surveys. Two pre-construction baseline surveys were undertaken in April 2000 and April 2006. During the construction phase which started in 2007, three surveys including the current one have been undertaken i.e. in September 2007, April 2008 and the present one, in April 2009. Unlike in all previous surveys in which monitoring was conducted at one transect upstream and three downstream transects, in the current survey, two transects, one upstream and the other,downstream of the BHPP were sampled with emphasis on the following aspects: 1. water quality determinants 2. biology and ecology of fishes and food webs 3. fish stock and fish catch including economic aspects of catch and 4. sanitation/vector studies (bilharzias and river blindness)

Aquatic ecology monitoring: water quality, fish, fish catch, sanitation and disease vectors: monitoring No.9, 9th – 12th September 2011

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

Fisheries ecology in the interface zone of Lake Nabugabo

This study was carried out in the interface zone of Lake Nabugabo, which is situated to the west of Lake Victoria. Four study sites were chosen from the south-western to the eastern ends of the euhydrophyte-dominated interface zone, which was about 10 km long, 10 to 50 m wide, 2 m deep and characterized by a thick layer of peat at the bottom. Nymphaea caerulea was the most dominant and widespread euhydrophyte species except in the eastern tip of the lake where it was replaced by Nymphaea lotus. Interspersed among these lilies was Ceratophyllum demersum in certain bays which were thought to be either water inlets or out-flows; Utricularia and Nymphoides indica were associated with monospecific stand of N. caerulea in the south- western end of the zone. The microinvertebrates were dominated by Copepoda (represented mainly by Cyclopoida), and Rotifera, with Cladocera occurring sporadically, while the macroinvertebrates were represented by Mollusca, Acarina, and seven insect orders of which Diptera (represented by Chironomidae) was the most dominant and widespread. Snails were found to have increased in abundance and distribution since the early 1960's. Nymphaea-Ceratophyllum mixed habitats had far more larval fishes and macroinvertebrates than monospecific stands of N. caerulea. Generally, the eastern end of the interface zone had more macroinvertebrates and larval fishes than the south-western end. Food habits of larval fishes were dominated by chironomid larvae; others consumed included detritus, aufwuchs and, periodically, cladocerans.

Survey of food network in Ovan Lake

Lake Ovan with about 9 hectares is regarded a semi-shallow lake with an average depth 5.2 meter. It is situated in Ghazvin Province, with a 1910 m high in mountainous regime. A monthly sampling was done at 3 stations studying the physicochemical and biological parameters in water and sediment at the Lake for a year. The temperature annual was measured 12.3°C and other parameters are pH as 8.8, oxygen 10, with total mean phosphate and nitrate as 0.14 & 0.8 mg/lit respectively. The chl.a mean was also measured 1.94 mg/lit. The ratio of N to P was calculated as 1:59, indicating a limiting factor for growth. Considering the trophic statues of the lake taking into account as above parameters, it is a mesotrophic lake with medium trophy. Altogether, 53 phytoplankton species were identified mostly diatoms, green algae and cyanobacteria. Although, 14 zooplankton species were identified with daphnia dominating the group. Macrobenthoses were also surveyed and 11 families were identified comprising mainly by Annelids, Gastropod, Bivalves and Insect Larvae. Other organisms were 2 dominate water plant including Phragmites australis covering at the edge of the lake and potamogeton sp in the inner parts, and also 2 fish species, common carp and Pike Perch. The diversity Shannon—Wiener index was calculated for main taxa groups with all figures lower than 3. Regarding the fish potential production of the lake based on Bramic & Lemke and morphoedophic index, it was calculated to be 20.4 kg/ha fish and a total of about 150 kg for the entire lake.