Wetlands and riparian zones as buffers and critical habitats for biotic communities in Lake Victoria

Despite their ecological and socio-economic importance, Lake Victoria's adjoining "swamps" and lake interface are among the least investigated parts of the lake. The "swamps" a term commonly equated to "wastelands" and the difficult working environment they present in comparison to open water, are major factors for the low level of attention accorded to shoreline wetlands. Moreover, definitions of wetlands highlighted for example in the Ramsar Convention as "areas of marsh, fern, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh or brackish, or salt, including areas of marine water, the depth of which does not exceed six metres" (Ramsar, 1971) were designed to protect birds (water fowl) of international importance. The Ramsar definition, which also includes oceans, has till recently been of limited use for Lake Victoria, because itdoes not fully recognise wetlands in relation to other public concerns such as water quality, biodiversity and the tisheries that are of higher socioeconomic priority than waterfowl. Prior to 1992, fishery research on Lake Victoria included studies of inshore shallow habitats of the lake without specific reference to distance or the type of vegetation at the shore. Results of these studies also conveniently relied heavily on trawl and gill net data from the 5-10 m depth zones as the defining boundary of shallow inshore habitats. In Lake Victoria, such a depth range can be at least one kilometre from the lake interface and by the 10m depth contour, habitats are in the sub-littoral range. Findings from these studies could thus not be used to make direct inferences on the then assumed importance of Lake Victoria wetlands in general

Evolution of the tilapia fishery with specific reference to the Nile tilapia (Oreochromis niloticus Linne)

As a fishery, the immensely large (c. 68,800 km2 ) Lake Victoria is a unique ecosystem which together with a riverine connection to the Lake Kyoga basin share a common endemic "Victorian" fish fauna (Greenwood 1966). Until the 1950s, the single socio economically most important species of fish in these two lakes was the native Oreochromis esculentus Graham (Graham 1929) even though the lake also contained a second native tilapiine, 0reochromis variabilis , and over 300 other fish species (Beauchamp, 1956)

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Fish Farm for quarter 1: January-March 2015

Source of the Nile (SON) fish farm is located at Bugungu in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm have a collaborative arrangement with NaFIRRI, a lead agency in fisheries research and innovations, to undertake quarterly environment monitoring surveys at the farm. The agreed areas for monitoring are: selected physico-chemical parameters (i.e. temperature, dissolved oxygen, pH, conductivity, secchi depth); total suspended solids (TSS); nutrient status; BOD5) and biological parameters (i.e. algae, zooplankton, macro-benthos and fish). Water and biological samples as well as field measurements were taken at 3 sites: within the fish cage rows (WIC/experimental), upstream (USC/control) and downstream (DSC) of the fish cages. The key research question was: Does fish cage operations have impacts on the water quality and aquatic biota in and around the SON cage fish farm? The environment monitoring surveys were projected to cover a full calendar year (i.e. from January to December). The first surveys were undertaken in 2011 and have continued on an annual basis since then. The present report presents field observations made for the fourth quarter survey undertaken in November 2014 and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota in and around the fish cage site

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Cage Fish Farm for quarter 4: October-December 2015

Source of the Nile (SON) Cage Fish farm is located at Bugungu in Napoleon Gulf, northern Lake Victoria, near the headwaters of the River Nile. NaFIRRI has, through a Public-Private collaborative partnership with SON management, undertaken quarterly monitoring of the cage fish farm since 2011. The objective of the environment monitoring is to track possible environment and biological changes as a result of fish cage operations in the area. The agreed study areas cover selected physical-chemical parameters i.e. water depth, transparency, column temperature, dissolved oxygen, pH and conductivity; nutrient status; and biological parameters i.e. algae, zooplankton, macro-benthos and fish communities. The fourth quarter survey, which is the subject of this report was undertaken during December 2015. Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aquatic biota. The present report presents field observations made for the fourth quarter survey undertaken in December 2015 and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota in and around the fish cage site

Report of Catch Assessment Survey of Lake Albert – Albert Nile conducted in July 2012

A Catch Assessment Surveys (CAS) with the overall objective of generating information on the fish production and commercial value of the fisheries of Lake Albert and Albert Nile system was implemented by the National Fisheries Resources Research Institute (NAFIRRI) in collaboration with the Department of Fisheries Resources (DFR), Local Government staff (FOs) and BMU members at selected landing sites on Lake Albert (12 landing sites) and Albert Nile (26 landing sites) in July 2012. A total 622 and 313 boat days on Lake Albert and Albert Nile respectively were sampled for a period of 9 days. Results indicate an annual landing of 151,600 and 5,900 tonnes (t) of fish with an estimated beach value of 122.5 and 14 Billion (UShs) from Lake Albert and Albert Nile respectively. Over 80% of the catch from Lake Albert comprised the small pelagic species; Neobola bredoi (Muziri) and Brycinus nurse (Ragoogi) followed by Nile perch (6%). However, due to low market value of the small fishes and the high prices attached to Nile perch for industrial processing and export market, the contribution of the latter to beach value rose to 34% of the total. The contribution of the light fishery based on small pelagic species (B. nurse and N. bredoi) are insignificant on Albert Nile. Even if the small pelagic species may be present in the river system, a light fishery based on these two is yet to be developed. Proportionally, Albert Nile still remain a multispecies fishery with over 20 fish species harvested commercially. Interestingly, the Albert Nile fishery still remains primitive with simple crafts and gears (mainly dugout canoes, traps, and gillnets). This could suggest that the more developed the system becomes the higher the level of transformation in its fisheries leading to simplification, characterized by reduction in multispecies nature and dominance of few species. Illegal gears especially undersized gillnet of mesh size less than 4 inches were the most dominant in the Lake Albert and Albert Nile fisheries. They captured large quantities of immature fish particularly when used to target Nile perch, Bagrus, Nile tilapia, and large Barbus spp. Their impact when used to target the smaller species (Ragoogi, Angara & Ngasia) is yet to be evaluated. A specific study to analyze selectivity and impacts of these nets is a recommended. However, the dominance of 1.5” mesh sizes especially on Albert Nile to target Angara, Ngassia and Barbus, is definitely destructive to their fisheries and should be checked forthwith. In addition, there is an emerging fishing method locally referred to as “Salsio or Luzira” whereby fishers stay on the lake from 3 days up to 2 weeks without returning to the landing site. They carry with them food and salt for processing the catches on the lake, and in the case of Albert Nile on make shift shelters on islands and in the game park. They normally use gillnets of 3-3½ inch mesh size and caught mainly Nile perch & Bagrus (Pethi & Munama). On return they land several tons of fish. Most of these Catches are not captured in the estimates presented in our analyses since we target daily fishing boats. The possible impacts of this fishing method should be studied and appropriate action recommended

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Fish Farm for quarter 2: April-June 2015

Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm have a collaborative arrangement with NaFIRRI to undertake quarterly environment monitoring of the cage site as is mandatory under the NEMA conditions. The monitoring surveys cover selected physical-chemical factors i.e. water column depth, water transparency, water column temperature, dissolved oxygen, pH and conductivity; nutrient status, algal and invertebrate communities (micro-invertebrates/zooplankton and macroinvertebrates/ macro-benthos) as well as fish community. The second quarter survey for the calendar year 2015, which is the subject of this report, was undertaken in June 2015. Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aquatic biota

Report of the Frame Survey of Lake Albert conducted in May 2012

Lake Albert and Albert Nile are a major source of fisheries resources sustaining the riparian communities in Uganda and the Democratic Republic of Congo (DRC). Like all shared bodies of Uganda Lake Albert and Albert Nile fisheries are faced with immense exploitation pressure one time described as the tragedy of the commons. In Uganda, the lake is shared by five riparian districts namely: Buliisa, Bundibugyo, Hoima, Kibaale and Nebbi. The lake covers a total estimated surface area of 5,270 square kilometers with approximately 60% within Ugandan waters. It is located in the western part of the great rift-valley at an altitude of 618 m above Sea level. The central parts of the lake are characterized by steep escarpments whereas the northern and southern parts lie in a plain of the rift valley. The plains are gently sloping, resulting in shallow swampy inshore waters in many places. The major inflowing rivers are the Semliki and Kafu in the south, and the Victoria Nile at the northern tip. The lake has a diverse fish fauna with a gradient of multi-species fisheries in different parts of the lake. The overall objective of the Frame Survey was to provide information on the facilities and services at landing sites and the composition, magnitude and distribution of fishing effort to guide development and management of the fisheries resources of Lake Albert and Albert Nile. The specific objectives were to provide information on: a) The number of fish landing sites; b) The facilities available at the fish landing sites to service the sector including accessibility; c) The service providers especially fisheries staff at fish landing sites; d) The number of fishers; e) The number and types of fishing crafts and their mode of propulsion; f) The number, types and sizes of fishing gears used on the lake and their mode of operation

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Fish Farm for Quarter 4: October – December 2017

The monitoring of water quality and biotic communities at Source of the Nile (SON) fish farm area, for quarter 4 (October – December) was undertaken in December 2017. The activity aimed at assessing possible changes in the water environment at SON cage area. The following parameters were assessed: water physico-chemicals and nutrients, algae, zooplankton, benthic macro invertebrates, and fish communities. Total depth was above 5.0 m (range: 5.63 – 9.74 m) at all sampled points and decreased towards the downstream of cages. Water transparency ranged from 1.26 – 1.48 in the cage area and 1.08 to 1.34 m away from the cages. Within the cage area, Dissolved Oxygen ranged from 5.7 – 6.4 mg/L at the surface, and 5.1 – 6.4 mg/L at the bottom, while in the non-cage areas, the range was 5.5 – 7.5 mg/L at the surface and 2.6 – 7.0 mg/L at the bottom. Temperature ranged from 27.0 – 28.0 o C at the surface and 25.5 – 27.5 o C at the bottom waters for all sites, and were within the optimal range (25 – 32 o C). pH in both surface and bottom waters was above 7.0 (range: 7.5 – 9.2) at all sites. Conductivity within cage area ranged from 100.5 – 102.6 μScm-1 in surface water and 101.8 – 112.1 μScm-1 in bottom water. In the non-cage areas conductivity ranged from 11.0 – 104.4 μScm-1 in surface water and 100.2 – 110.0 μScm-1 at the bottom. Ammonium nitrogen concentration during December was less than 0.02 mg/L at all sites (0.007 – 0.018 mg/L within the cage sites, and 0.012 – 0.019 mg/L in the non-cage sites). Nitrite nitrogen ranged from 0.002 – 0.169 mg/L in the cage area, and 0.003 – 0.057 mg/L in the non-cage areas. Similar to previous records of June and September 2017, nitrate nitrogen concentration generally increased towards the downstream site, being lowest at RPT (0.041 mg/L) and highest at DSC (0.204 mg/L). Soluble reactive phosphorus was less than 0.005 mg/L at all sites, and varied within narrow margin (range: 0.003 – 0.0048 mg/L in cage sites, and 0.0032 – 0.0047 mg/L in non-cage sites). The TP concentration ranged from 0.085 – 0.107 mg/L in the cages, and 0.090 – 0.118 mg/L in the non-cage sites and was higher than recorded in September (0.038 – 0.044 mg/L in the cages and 0.04 to 0.109 mg/L away from cages). Total nitrogen concentration was in the range of 0.138 – 0.553 mg/L within cage area and 0.421 – 0.513 mg/L in non-cage areas. The concentration of TSS ranged from 0.76 – 4.33 mg/L in the cage area and 0.57 – 2.76 mg/L in the non-cage areas. The phytoplankton community was composed of blue-green algae, green algae and diatoms, dominated by blue-green algae. The abundance of algae was higher in the non-cage areas (mean:7.20 ± 2.14 mm3L-1, Range: 5.15 – 10.20 mm3L-1) than recorded in the cage areas (mean: 6.0 ± 0.71 mm3L-1, Range: 5.30 – 6.98 mm3L-1), similar to observations of September 2017 (5.6 mm3L-1 in the non-cage sites). At all sampled points, blue-green algae contributed >70% of total abundance. Total zooplankton abundance ranged from 982,213 – 1,310,830 ind.m-2 in the non-cage sites, and 740,601 – 1,503,130 ind.m-2 in the cage areas. Similar to observations of September 2017, the upper cage site (WIC3 and WIC4) presented lower zooplankton abundance (mean: 788,954 ± 68,381 ind.m-2) when compared to the lower cage site with mean abundance of 1,128,232 ± 530,186 ind.m-2. Like in the previous sampling periods, copepods were the numerically dominant group (92.69 – 97.22 % of total zooplankton abundance) at all sampled points, with no major differences between cage and non-cage areas. The high abundance of copepods was attributed to the abundance of the juvenile stages (copepodites and Nauplius larvae) which contributed 83.72 – 92.78% of the total zooplankton abundance and this was mainly due to the Nauplius larvae (66.4 – 83.2 %). Cladocera relative abundance ranged from 0.32 – 3.98% while that of rotifers ranged from 1.55 – 3.74%. The macro-benthic community comprised molluscs, annelids and arthropods. Taxa richness ranged from 5 – 11 taxa in the cage area, and 7 – 9 taxa in the non-cage areas. The abundance of benthic invertebrates within the cage area ranged from 1,134 – 2,416 ind.m-2 and this was higher than previously recorded in September (294 – 1,415 ind.m-2). In the non-cage sites abundance was in the range of 420 – 3,992 ind.m-2. Oligochaete annelids which are reported to be very tolerant to pollution contributed 0 - 28 % of the abundance of benthos at cage sites and 3 - 20% at the non-cage sites. Diptera made the greatest contribution at almost all sites, with the percent abundance being higher in non-cage sites (40 – 86%) than what was recorded in the cage sites (37 – 82%). Chironomus spp. and Chaoborus sp. were the main contributors to the observed Diptera abundance at all sites. Six fish species, including haplochromines (Nkejje) as a single species group, were recorded in the vicinity of the cages during December 2017. Five fish species were recorded from upstream the cage site, four species from within cage area, and two species from downstream the cages. Overall mean catch rates were 1.8 fish/net/night and 148.6g/net/night compared to 1.7 fish/net/night and 175.4g/net/night recorded in September 2017. By weight, catch rates in December 2017 were highest upstream the cage site (312.1g/net/night) and also by numbers (3.1 fish/net/night). Four species of haplochromines were recorded in the vicinity of the cages during the survey of December 2017 compared to six species recorded in September 2017. The overall catch rate for the haplochromines, in December 2017 was 1.7fish/net/night and 27.5g/net/night compared to 3.4 fish/net/night and 62.3g/net/night recorded in the previous survey of September 2017. Among the fish species examined during December 2017 survey, most of the haplochromine cichlids (88.9%) were mature but only 50% breeding. Only one specimen of L. niloticus was mature and breeding. All S. afrofischeri and S. victoriae specimens examined were mature and in breeding condition while M. kannume was immature. The diet of fishes encountered comprised mostly of fish and insects, which are known natural foods of the fish species. Infection by fish parasites during the survey of December 2017 was not noticed in any fish recorded from the experimental gillnets. The overall observation on concentrations of nutrients, levels of physico-chemical variables, and biotic communities indicated minimal impact of cages on water quality. The farm should therefore continue adhering to the best environmentally sustainable aquaculture practices, especially continuing with fallowing or rotation of cages to allow resident organisms maintain their natural population densities, distribution and community structure in the area; reducing excess uneaten feed and other suspended materials which would impact on nutrient status and biota; as well as wise use of any chemicals in the area