Browsing by Author "Bassa, Samuel"

Now showing 1 - 2 of 2
  • Publication
    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, Richard
    Riverine 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
    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, Zachary
    Persistent 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.