Browsing by Author "Getabu, Albert"
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Publication An Overview of Heavy Metal Pollution in the Western Indian Ocean (WIO) region of Kenya: A Review(Journal of Aquatic Terrestrial Ecosystems, 2023-06-20) Nyamora, Jane Moraa; Njiru, James; Nyakeya, Kobingi; Getabu, Albert; Muthumbi, AgnesThis study is a review on heavy metal pollution in the Western Indian Ocean (WIO) region of Kenya. The review examines heavy metal pollution of copper, lead, cadmium, iron and zinc that are toxic to marine life and human health; and identifies gaps for future monitoring and assessment. Each pollutant was addressed in order to determine their status in the environment, sources and their effect on biological systems, marine organisms, and human health. Although the concentration levels of these metals are still low and within the recommended standards of global regulating bodies, there is little information in relation to their effects along the food web, human health and how they affect the population dynamics of fish species. Apart from regular monitoring and assessment further research on their effects in the food web and an assessment of human health is recommended.Publication Assessment of the Value of the Small Scale Fish Farming Enterprises in Nyamira County, South West Kenya(International Journal of Innovative Research and Advanced Studies (IJIRAS), 2019-09) Lagat, Caroline J.; Kibet, Noah; Omasaki, Simion; Getabu, AlbertFish farming is relatively recent compared to subsistence crop farming in Nyamira County. It is becoming significant due to its contribution to nutrition, self employment and income generation. A Cost Benefit Analysis was conducted from March-October 2016, to estimate its viability. Semi structured questionnaire was used to collect data from 320 farmers using simple random sampling technique. Focused group discussion schedules were administered to three groups of ten farmers to collect extra data. Further information was collected on data returns of harvests from farmers and from interview schedules of fifteen key informants. Data were analysed using Statistical Package for the Social Science (SPSS) version 20.0 and Excel spreadsheet programme. Chi square (χ 2 ) was used to test if there were significant differences between profits obtained by farmers at p=0.05. Results indicated that the mean input cost per farmer ranged from Ksh 46.08±0.08-Ksh 50.34±58m-2 . A positive correlation between total feed costs and net income (R) ranged from 0.479-0.519. Cost Benefit Ratio indicated that Borabu had the highest (4.66) followed by Manga (1.51) and by Nyamira North (1.31). A similar trend was observed on Rate of Returns on Investment with Borabu having 3.64, Nyamira North 0.44 and Manga 0.75. New farmers obtained low net income due to costs incurred on construction of new ponds. Most commonly used feeds were vegetables, kitchen remains and Rastrineobola argentea. This study demonstrates that small scale aquaculture can be profitable when appropriate inputs are provided.Publication Ecological integrity of a medium-sized river of a lake basin towards ecosystem health management(Wiley, 2023-10-13) Osure, George Owiti; Aura, Christopher Mulanda; Getabu, Albert; Omondi, Reuben; Basweti, EvansThis study demonstrates the use of a multi-metric Fish Index of Biotic Integrity (FIBI) for assessment of ecological health of a medium-sized river, under a gradient of human disturbances in the Kenyan side of the Lake Victoria Basin (LVB). Development of the index is based on water quality, river habitat quality and fish community attributes. The river was sampled from 2019 to 2020 during wet and dry seasons of the year at nine selected sites along its length based on the level of human disturbance. A total of nine metrics representing the structural and functional organization of fish communities were qualified using the separation power of Mann–Whitney U test (p < .05). Metric values at unimpaired, intermediate, impaired and no-fish sites were used to establish the scoring criteria using inter-quartile ranges. A 1, 3, 5 scoring system representing high, fair and slight deviation from the best site, respectively, was used in the final FIBI development. River mouth station had the highest FIBI score of 43, with extensive natural riparian buffer vegetation (>20 m) and 18 fish species implying least human disturbance. The midstream section had intermediate FIBI scores of 34–36, with wide natural riparian buffer vegetation (10–20 m) and 6–9 fish species that represented moderate human disturbance. The upstream section had the least FIBI score of 0, with no fish and narrow riparian buffer vegetation (<5 m) that indicated notable degradation. This study presents the preliminary results of using fish and habitat metrics for development of an Index of Biotic Integrity (IBI) for a medium-sized river in a lake basin, as a decision-making support tool for effective management and conservation of water resources. The study recommends restoration of river habitat quality for improved ecological integrity of rivers in the Lake Victoria Basin.Publication Ecosystem Integrity of the Upper Victoria Nile in East Africa based on Habitat and Fish Species Biotic Indices(National Agricultural Research Organization, (NARO), 2019) Bassa, Samuel; Owiti, Dickson Oteino; Ogello, Eric; Getabu, Albert; Muhoozi, Levi Ivor; Nakiyende, Herbert; Nkalubo, Winnie; Muhumuza, Elias; Mbabazi, Dismas; Nyanichoka, Orina Enock; Balirwa, John Stephen; Taabu, Anthony Munyaho; Olwa, RichardRiverine ecosystems are continuously been compromised by human activities resulting in threatening their integrity. In this study, integrity of Upper Victoria Nile River was assessed using habitat quality and fish biotic indices. Experimental gillnetting was done bi-annually in 9 stations along the river from 2008 to 2018. Nine habitat metrics were used to estimate habitat quality index at every sampling station. Fish sampled, were sorted, identified to species level, and weighed. Counts of introduced and indigenous as well as tolerant and intolerant species were recorded to generate species richness. A total of 10.642 fish, 65 species belonging to nine families were recorded. Dominant species were Lates niloticus 62.79%, Oreochromis niloticus 23.51%, Mormyrus kannume 13.64%; other species were ≤0.06%. Tolerance and trophic guild showed carnivores (61.5%), omnivores (21.5%) and detrivores (16.9%).Mean habitat quality index, total fish catch and fish-based index of biotic integrity varied among stations with highest record of 26.6±6.9, 289.2±51.8 and 30.6±7.9 at sampling station (ST4) respectively. The lowest was 19.4±7.3, 93.1±13.2 and 26.7±6.8 at sampling station (ST2) respectively. On a spatial basis, indices recorded significant differences among stations (p < 0.05). Results indicated a fair fisheries biodiversity that need better conservation management of habitat type of the upper Nile.Publication Hydrogeophysical Characterization of a Weathered-Fractured Aquifer System: A Case Study of Olbanita, Lower Baringo Basin, Kenya Rift(Scientific Research, 2019-11) Sosi, Benjamin; Barongo, Justus; Getabu, Albert; Maobe, SamsonGroundwater yields in the Kenya Rift are highly unsustainable owing to geological variability. In this study, field hydraulic characterization was performed by using geo-electric approaches. The relations between electrical–hydraulic (eh) conductivities were modeled hypothetically and calibrated empirically. Correlations were based on the stochastic models and field-scale hydraulic parameters were contingent on pore-level parameters. By considering variation in pore-size distributions over eh conduction interval, the relations were scaled-up for use at aquifer-level. Material-level electrical conductivities were determined by using Vertical Electrical Survey and hydraulic conductivities by analyzing aquifer tests of eight boreholes in the Olbanita aquifer located in Kenya rift. VES datasets were inverted by using the computer code IP2Win. The main result is that InT = 0.537(1nFa) + 3.695, the positive gradient indicating eh conduction through pore-surface networks and a proxy of weathered and clayey materials. An inverse (1/F-K) correlation is observed. Hydraulic parameters determined using such approaches may possibly contribute significantly towards sustainable yield management and planning of groundwater resources.Publication Occurrence and distribution of Organochlorine Pesticide Residues in Water and Sediments of Earthen Fish Ponds in South Western Kenya(Africa Journals Online, 2019) Nyaundi, Joseph Kiyuka; Getabu, Albert; Onchieku, James; Kinaro, Zachary; Bassa, Samuel; Nyamweya, Chrisphine; Nyaboke, Hilda; Getenga, ZacharyPersistent organochlorine residues in the environment are a threat to ecological health of aquatic organisms and pose a health risk to both animals and human consumers. Organochlorine pesticides were determined in water and sediments collected during wet and dry season from selected riverine and earthen fish pond sites in high altitude catchment areas within Kuja River (Kenya) between August 2016–May, 2017. Analysis of DDT and metabolites, Hexachlorocyclohexanes (HCHs) isomers and cyclodienes using a gas chromatograph (GC), and electron capture detector (ECD), confirmed using GC - Mass Spectrometry (MS). Mean (± Standard error) results of DDTs, cyclodienes and HCHs in pond waters were:- below detection level (BDL) to 0.27±0.03µg/L, BDL to 0.11±0.00µg/L, and 4.39±1.01µg/L respectively; and BDL to 0.23±0.01µg/L, 1.20±0.005µg/L, and 1.71±0.02µg/L in river water respectively. Sediment mean OCPs contents were significantly (p<0.05) higher for Dieldrin (3.043±0.43µg/kg), Endrin (2.56±0.460µg/kg), Heptachlor (3.61±0.02µg/kg) DDT (2.97±1.32µg/kg), Endosulfan (6.31.27±1.051µg/kg), Methoxychlor (2.15±1.641µg/kg) and Lindane (2.96±1.32µg/kg), respectively. A longitudinal spatial distribution pattern was noted for both water and sediment OCPs contents, demonstrating that cyclodienes are predominant contaminants in point and non-point sources in water courses. The study recommends continuous monitoring of OCPs in upstream catchment areas for informed management and policy decisions on pesticide use.Keywords: Kuja-Migori River; Organic contaminants; Organochlorine Pesticide.Publication Organochlorine Contaminants in Nile Tilapia, Oreochromis niloticus (Linnaeus 1758) in Densely Populated Areas of South-Western Kenya(2020) Nyaundi, Joseph; Getabu, Albert; Mwamburi, Job; Onchieku, James; Kinaro, Zachary; Ogendi, George; Babu, Miruka; Gichuru, NicholasConcentrations of OCP (Organochlorine Pesticide) residues were determined in cultured Nile tilapia (Oreochromis niloticus) fish in target stations within 1st order wetland of River Kuja, Kenya, between February-November, 2017. The aim was to assess the residue levels in wild and pond cultured fish within a heavily populated agricultural area of South Western Kenya. Biota samples were analysed for selected HCHs (Hexachlorocyclohexane) isomers, DDT (Dichlorodiphenyltrichloroethane) and metabolites and cyclodienes pesticide residues using GC-ECD (Gas Chromatography Equipped with Electron Capture Detector). Most of OCPs observed were BDL (Below Detection Limit) to detectable levels. Larger percentages (> 50%) of DDTs and HCHs were BDL and exhibited consistency, with significant (p < 0.05) differences in mean contamination levels in fish within the wetland, with average muscle tissue pesticides concentrate ranging between 0.229-2.541 g/kg for Nile tilapia. Most dominant isomer in target species was Lindane (-HCH) (3.417 ± 0.983 g/kg) and Endosulfans. Mean Endosulfan sulfate was 2.499 ± 0.071 g/kg d.w. and most frequently detected, and Methoxychlor (2.235 ± 1.459 g/kg), respectively. Mean Aldrin and Dieldrin was 2.028 and 0.574 g/kg d.w. Concentration for DDT and its metabolites was 0.27-3.71 g/kg for p, p’-DDE (DichlorodiphenylDichloroEthene), BDL-1.098 for p, p’-DDD (DichloroDiphenylDichloroEthane), and 0.105-3.518 g/kg for p, p’-DDT with significant differences in mean values and ranges whose levels were below the WHO (World Health Organization) maximum acceptable thresholds of 0.2, 2, 20 and 5.0 g/kg in fish and sea food.Publication Relationship Between Aquifer Processes and Groundwater Quality: A Case of Olbanita Aquifer System, Lower Baringo Basin, Kenya Rift(Sage Journals, 2019-01-01) Sosi, Benjamin; Getabu, Albert; Maobe, Samson; Barongo, JustusA hydrogeochemical relation has been hypothesized through the analyses of physiochemical data of a fractured volcanic rock aquifer located in the Lower Baringo Basin, Kenyan Rift. Data sets included 15 individual metrics determined in 42 dry and wet season water samples obtained from 6 boreholes in the area. Aquifer evolutionary theory was postulated using sequential principal component analysis (PCA) and hierarchical cluster analysis. To eliminate the effects of scale dimensionality, PCA decomposed the variable data into 4 factors, namely, electrical conductivity, salinity, alkalinity, and carbonate equilibrium with external pH control for the dry season and salinity, carbonate equilibrium with external pH control, alkalinity, and electrical conductivity for the wet season. The main result depicted a major shift in the variability factor from electrolytic conductivity (34.8%) in the dry season to salinity (23.5%) in the wet season. Ward’s linkage cluster analysis partitioned the aquifer into 2 spatially discrete associations; the western and the eastern entities, respectively, in spite of their shared recharge area. These agglomerative scheduling validated in an integrative approach (with groundwater flow predictions using a calibrated petrophysical groundwater model for the area) linked the 4 factors to aquifer processes and 3 pathways: fault permeability, weathering processes, and water-rock interaction. Statistical approaches are, therefore, useful in the conceptualization of pollutant sources and their attenuation for effective groundwater quality management.Publication Some aspects of the reproductive biology of Labeo victorianus (Boulenger, 1901) from Kuja-Migori River basin, Kenya(Journal of Fisheries, 2022-03-19) Kembenya, Elijah; Getabu, Albert; Njiru, James; Omondi, ReubenLabeo victorianus is an endemic species to Lake Victoria basin and also a species threatened with extinction status. This study investigated reproductive biology of L. victorianus from Kuja- Migori River basin, Kenya with a view to determining the length weight relationship (LWR), condition factor, fecundity, egg diameter gonado-somatic index (GSI), length at 50% maturity (LM50) and sex ratio. Sampling was done by electrofishing from January 2018 to June 2019. The LWR showed a negative allometric pattern (p < 0.05). The mean condition factor for combined sexes was 1.02. Fecundity ranged from 47842 – 101902 eggs (mean ± SD: 83663 ± 2605 eggs) and correlated highly with body size (r2 = 0.9137). Egg diameter ranged from 0.5 – 0.7 mm. Mean GSI was 6.3 ± 1.6 and 2.8 ± 0.45 for females and males respectively. The LM50 was estimated at 18 cm total length (TL) and 20 cm TL for males and females respectively. Sex ratio did not differ from the expected 1:1. This species has a high fecundity with small sized eggs and males attain sexual maturity earlier than females. The findings of this study provide useful information towards sustainable conservation of L. victorianus in the Lake Victoria basin.Publication Spatial variation in diversity, distribution, and abundance of macroinvertebrates and their response to physicochemical param- eters in River Nyakomisaro, kisii-Kenya(IJTHF, 2020-02-20) Jomo, Boston; Omondi, Reuben; Getabu, Albert; Orwa, PatrickAquatic animal and plant diversity of tropical aquatic ecosystems are severely threatened by frequent anthropogenic activities. The study investigated spatial variation in macroinvertebrate community and physicochemical parameters of River Nyakomisaro from July to December 2016. Five sampling sites were selected and a pool, a rie and a run identied in each site for sampling. Kick sampling was employed in collecting macroinvertebrate samples while selected physicochemical parameters were determined in situ using a water quality multi-parameter meter model 85–15 ft YS1. A total of 6,104 macroinvertebrates belonging to 30 genera, 22 families and 10 orders were recorded. The highest diversity (2.719 ± 0.018) was recorded in station 1 while station 5 had the lowest diversity (1.229 ± 0.026). The highest abundance was recorded in station 5 with 1,948 macroinvertebrates dominated by Chironomids which are highly tolerant to perturbations while station 1 recorded the lowest abundance of 473 macroinvertebrates and dominated by macroinvertebrate communities that are sensitive to environmental pollution. Analysis of variance (ANOVA) showed signicant dierences (p<0.05) in diversity, abundance, and distribution of macroinvertebrates of River Nyakomisaro. Headwater stations had taxa that thrive in undisturbed waters with a reduction of genera that are sensitive to perturbations such as Ephemeroptera, Plecoptera, and Trichoptera in downstream stations. This was a clear indication of pollution of the waters downstream. This response makes macroinvertebrate communities in River Nyakomisaro good bio-indicators of water quality. Therefore, the ndings of the current study can form a basis for the establishment of strategies for conservation, protection, and restoration of macroinvertebrates and the integrity of river NyakomisarPublication Spatial-temporal composition, abundance and diversity of algal communities in River Malewa of Lake Naivasha Ramsar Basin, Kenya(Integrity Research Journals, 2022-04-30) Obegi, Beatrice; Njiru, James; Getabu, Albert; Gichana, ZipporahABSTRACT: Algae and algal communities are potentially vulnerable to climate change and consequently can be depleted or be extinct hence the current debate on global biodiversity. Using a 30 µm phytoplankton net, triplicate samples were picked monthly from 10 stations in River Malewa from November 2020 to December 2021. A total of 360 samples were picked the whole study period. The study examined taxonomy, composition, abundance, diversity, and distribution. Counting and identification was done using Sedwick- rafter cell counting chamber with a Binocular compound microscope. Results indicated 89 species of phytoplankton were identified. 86 species were identified in the river while additional 3 more species were identified in the lake. Bacillariophyceae (Diatoms) dominated in lotic sites with 50%, Cyanophyceae was 17%, Chlorophyceae 16% and Myxophyceae was 6% while the least dominant was Euglenophyceae with 4%, Chrysophyceae (3%), Xanthophyceae, Rhodophyceae and Dinophyceae with 1% each. Two points at the lake showed a high dominance in Chlorophyceae with 63%, Xanthophyceae 21% and Chrysophyceae 14%, while Bacillariophyceae was 1% and the rest of the groups were 0%. The abundance showed RM1 and RM4 had abundance of 4.8 x 105 cells/mm3. Site RM9 and RM10 being lacustrine recorded highest abundance with 1.24 x 106 and 1.29 x 106 respectively. RM3 recorded abundance of 6.2 x 105 cells/mm3, RM3 was 7.3 x 105 cell/mm3 and RM5, RM6, RM7 and RM8 recorded abundance of 8.5 x 105, 9.2 x 105, 7.5 x 105 and 7.9 X 105 cell/mm3 respectively. High value of Shannon-Wiener's index (H ') was recorded in RM6 (1.556), followed by RM4 (1.521), RM7 (1.504), and lowest was RM 10 (1.141), RM5 (1.299), RM1 (1.398), RM3 (1.403), RM2(1.474) and RM8 (1.473). Management issues and effects of existing human pressures, such as damping, urbanization and nutrient enrichment on river ecosystems should be studied to fill gaps in knowledge on phytoplankton monitoring on rivers and streams.Publication Water quality, phytoplankton composition and microcystin concentrations in Kisumu Bay (Kenya) of Lake Victoria after a prolonged water hyacinth infestation period(Lakes and Reservoirs: Research and Management, 2021-12-01) Miruka, Jared Babu; Getabu, Albert; Sitoki, Lewis; James, Onchieku; Mwamburi, Job; George, Ogendi; Chrisphine, Nyamweya; Odoli, CyprianThe production of phytoplankton (algal) toxins and their control is of concern because of the need to reduce their negative impacts on water quality and facilitate effective management of algal blooms. The present study was conducted between September 2017 to May 2018, focusing on Kisumu Bay in the Kenyan portion of Lake Victoria, in order to establish the magnitude of potential impacts on phytoplankton composition and microcystin following a prolonged presence of water hyacinth coverage between 2013 and 2018 within the gulf, with an estimated coverage range varying between 644 and 1224 ha. Triplicate samples of physico‑chemical parameters, nutrients, phytoplankton, chlorophyll‑a and algal toxins (N = 88) were collected at eleven sampling sites to determine their spatio‑temporal variability. The main identified algal taxa comprised Cyanophyceae, Bacillariophyceae, Chlorophyceae, Euglenophyceae, Zygnematophyceae and Dinophyceae. The most dominant algal species were Microcystis aeruginosa (25%), Merismopedia spp. (23%) and Anabaena flos‑aquae (16%). Enzyme‑linked immunosorbent assay (ELISA) technique was used to determine microcystin (MC) toxins in the water. Mean MC‑LR and MC‑YR concentrations were significantly correlated (R2 = 0.972), exceeding WHO standards at three sampling sites (Coca Cola, 2.84 ± 4.76; Kisumu pier, 1.78 ± 1.87; Midpoint, 1.44 ± 2.71 μg/L MC–LR). There were significant temporal variations (p < .05) in the SRP, TN, NO3‑N, NO2‑N, NH4‑N, SiO2‑Si, MC‑LR, MC‑YR, dissolved oxygen (DO), total dissolved and suspended solids (TDS; TSS), turbidity, electrical conductivity, Secchi depth, temperature and pH levels. The water depth, TP and DO also vary spatially. The nitrogen to phosphorus concentration ratios differed from the expected N:P ratio of 16:1, indicating a highly eutrophic status. The disproportionate ratio of total phosphorus and total nitrogen in the bay may be responsible for the enhanced cyanobacterial blooms it exhibits. The results of the present study provide useful information and data for formulating regulations for water quality management.