{"title":"Biological and life-history parameters for Labeo rosae Steindachner, 1894 and Oreochromis mossambicus (Peters, 1852) from Flag Boshielo Dam, Olifants River, South Africa","authors":"HA Hlungwani, SM Marr, O. Weyl, JR Sara","doi":"10.2989/16085914.2023.2173136","DOIUrl":"https://doi.org/10.2989/16085914.2023.2173136","url":null,"abstract":"Inland fisheries contribute towards food security for rural communities living close to large aquatic systems. However, sustainable inland fisheries rely on accurate biological information for the target species at the proposed fishery location. In this study, the biological information for Labeo rosae Steindachner, 1894 and Oreochromis mossambicus (Peters, 1852) were determined at Flag Boshielo Dam, Olifants River system, Limpopo province, as part of a larger study to evaluate a small-scale gill net fishery at this impoundment. Nine fish surveys were conducted from February 2016 to April 2017 using mixed sampling gears. Labeo rosae exhibited positive allometric growth (b > 3) while O. mossambicus displayed negative growth (b < 3). For L. rosae, the asymptotic length was 391 mm L ∞, and the length-at-50% sexual maturity 165.8 mm. For O. mossambicus, the asymptotic length was 420 mm L ∞, and the length-at-50% sexual maturity 166.5 mm. Both species population stocks showed signs of exploitation. Total mortality for L. rosae was 0.57 yr−1 with a fishing exploitation of 0.21 yr−1, while total mortality of 0.78 yr−1 and fishing exploitation of 0.50 yr–1 were estimated for O. mossambicus. The biological data collected, apart from the length–weight parameters for O. mossambicus, are suitable for conducting a fisheries assessment for these species at Flag Boshielo Dam.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"199 - 212"},"PeriodicalIF":1.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49644099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
JK Nyaundi, SK Omasaki, J. Babu, NM Mwirigi, R. Omondi, GA Mwayulj, S. Bassa
{"title":"Dissipation of environmental DDT and its metabolites in selected rivers of south-western Kenya","authors":"JK Nyaundi, SK Omasaki, J. Babu, NM Mwirigi, R. Omondi, GA Mwayulj, S. Bassa","doi":"10.2989/16085914.2023.2174930","DOIUrl":"https://doi.org/10.2989/16085914.2023.2174930","url":null,"abstract":"Rivers are the main source of domestic and industrial water supplies in Kenya. In this study, water sampling was done at eight upstream sites in the Kuja River catchment, Kenya, between October 2016 and April 2017, specifically to test for residue levels of the organochlorine pesticide, dichlorodiphenyltrichloroethane (p,p′-DDT), and its degradation products, dichlorodiphenyldichloroethylene (p,p′-DDE) and dichlorodiphenyldichloroethane (p,p′-DDD). The analysis was performed with gas chromatography coupled with electron-capture detection in an autosampler. Concentrations of these residues in the surface water samples ranged from below detection limit (BDL) to 1.1113 μg l-1 in the wet season, and from BDL to 2.007 μg l-1 in the dry season. Overall, the highest mean residue concentration was for p,p′-DDT (0.9669 ± 0.2994 μg l-1). The lowest mean concentration in the dry season was that of p,p′-DDE (0.1824 ± 0.0964 μg l-1), and in the wet season it was p,p′-DDD (0.0610 ± 0.0038 μg l-1). From our results it is evident that DDT is still in use and detectable in the study area, though the mean levels detected were below the acceptable thresholds for natural water as suggested by the World Health Organization (WHO). Except for a slightly higher mean spatial distribution of the metabolite p,p′-DDT, the resides were recorded as below the maximum admissible concentrations of pesticide residues in drinking water, as set out in WHO guidelines and by Kenya’s National Environment Management Authority (NEMA). Monitoring organochlorine pesticide contamination levels in Kenya’s water resources should be scaled up to leverage potential for a sustainable blue economy and in safeguarding human and environmental health.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"115 - 122"},"PeriodicalIF":1.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41783826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Asase, TL Lauridsen, P. Sanful, Eek Quansah, F. Nunoo
{"title":"Status of diversity, abundance and seasonal variations of gill net catches of cichlids in Lake Bosumtwi, Ghana","authors":"A. Asase, TL Lauridsen, P. Sanful, Eek Quansah, F. Nunoo","doi":"10.2989/16085914.2023.2201286","DOIUrl":"https://doi.org/10.2989/16085914.2023.2201286","url":null,"abstract":"The cichlids in Lake Bosumtwi are under increasing pressure with a recent build-up in local fishing pressure. This study was conducted to assess the status and seasonal catch rates of fish species using gillnets over a two-year period. Four species and one introduced fish belonging to the Cichlidae family were encountered in the study. Coptodon discolor (Günther, 1903) was the most abundant species, making up 75.5% of the total fish caught (100.1 kg). Tilapia busumana (Günther, 1903) was the least abundant species, representing only 0.6% of biomass. Catch per unit effort was significantly affected by seasonality; however, species diversity, richness and evenness were not influenced by seasonal variations. The highest catch rates (975.62 g net−1 night−1) were recorded in the minor wet season (August to November). No statistical differences were detected in the diversity indices estimated for all three seasons of study. The key physico-chemical parameters (conductivity, salinity, temperature and pH) measured were within the tolerance range for tilapia survival and growth, with the exception of dissolved oxygen that decreased below 3 mg l−1 during the lake’s deep mixing events in August. Overall, physico-chemical factors explained 75% of fish catches, with salinity levels correlating significantly with catch per unit effort.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"213 - 222"},"PeriodicalIF":1.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44709697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Assessment of metal pollution in sediment and its impact on the macrobenthic community of Richards Bay Harbour, South Africa","authors":"J. Izegaegbe, L. Vivier, H. Mzimela","doi":"10.2989/16085914.2023.2197462","DOIUrl":"https://doi.org/10.2989/16085914.2023.2197462","url":null,"abstract":"Port and industrial activities often cause contamination of estuarine sediments, yet information on sediment metal contamination in Richards Bay Harbour is limited. This study examined the extent and ecological relevance of metal contamination using sediment quality guidelines, pollution indices, macrobenthic community structure and the biotic index M-AMBI. Sediment samples for metal and macrobenthic analyses were collected quarterly at seven sites during 2016−2017 using a Van Veen sediment grab sampler. Sediment samples were acid digested using a microwave digester and analysed for metal concentrations using ICP-OES. Highest metal concentrations (Cd, Cr, Cu, Ni and Zn) were associated with areas most affected by industrial activities, while concentrations of most metals at the remaining sites were low. Pollution indices confirmed significant enrichment of Cd, Cr and Cu in bulk terminal sediment. Sediment quality guidelines revealed potential toxicity associated with Cu, Cr and Ni. The dominant taxa were Halmyrapseudes digitalis (two sites), Mediomastus capensis (three sites) and Sigambra parva (two sites). A significant inverse correlation existed between pollution indices and M-AMBI scores, confirming the adverse effect of metals on habitat quality. The need for a biomonitoring programme incorporating relevant biotic and abiotic indices is emphasised to assess the long-term effects of sediment contamination on aquatic communities in South African estuarine environments.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"123 - 137"},"PeriodicalIF":1.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45471509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Ainou, J. Panfili, A. Pariselle, M. Labonne, H. Louizi, A. Benhoussa, O. Berrada Rkhami, J. Agnese
{"title":"Life-history traits in two invasive species of tilapias in Morocco","authors":"H. Ainou, J. Panfili, A. Pariselle, M. Labonne, H. Louizi, A. Benhoussa, O. Berrada Rkhami, J. Agnese","doi":"10.2989/16085914.2023.2197464","DOIUrl":"https://doi.org/10.2989/16085914.2023.2197464","url":null,"abstract":"Life-history traits (LHT) of Oreochromis niloticus in the Sidi Mohamed Ben Abdellah reservoir (BA reservoir) and Oreochromis aureus in the Nador Channel were studied and compared with those of other populations in the world. Specimens were collected between June 2018 and June 2020. Females of both species were smaller at first sexual maturity than males (O. niloticus: 204 vs. 255 mm, O. aureus: 147 vs. 158 mm). The age of maturity for each species was estimated from seasonal otolith growth marks, based on the von Bertalanffy growth function. The asymptotic length was higher in O. niloticus (males 296 mm and females 339 mm) than in O. aureus (males 171 mm and females 169 mm). Based on a literature survey and the results of this study, the type of ecosystem (reservoir vs. river) influenced growth performance indices (φ and φ′) in both species, with reservoirs leading to a higher asymptotic length in both O. niloticus and O. aureus than rivers. Moroccan populations presented the lowest growth index in the populations assessed. These observations suggest that while both invasive species were able to colonise and adapt to their new environments, this was at the expense of limiting their growth and reducing their size at first sexual maturity.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"223 - 235"},"PeriodicalIF":1.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44894984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Diversity of euglenoids in a drinking water source in Burkina Faso (West Africa): implications for sustainability and water quality","authors":"M. Ouattara, F. Zongo, Bilassé Zongo","doi":"10.2989/16085914.2023.2170315","DOIUrl":"https://doi.org/10.2989/16085914.2023.2170315","url":null,"abstract":"Euglenophyta are a group of algae that occur in water polluted by organic matter, which makes them a good indicator for organic pollution. This study aimed to determine the diversity of Euglenophyta, the environmental conditions favourable to their development and their implication in the sustainability and quality of the water in Loumbila reservoir. Algal and chemical water samples were collected monthly between January 2015 and June 2015. Phytoplankton species were identified under a light microscope using a Fuchs-Rosenthal chamber for algal cell counting. In total, 34 species of Euglenophyta were identified, four of which are new to the algal flora of Burkina Faso. The abundance and number of species of the genera Euglena and Phacus were significantly (p < 0.05) higher in the dry season. Euglena deses, Euglena texta, Euglena caudata, Phacus lefevrei, Phacus ranula and Phacus orbicularis were identified as indicator species of high nutrient concentration. The abundance of these genera was positively correlated with pH, dissolved oxygen, water transparency, conductivity, nitrates and orthophosphates. This study on the diversity of Euglenophyta enabled us to identify indicator species of reservoir pollution and the environmental factors favourable to their development. This can be used to guide the future water quality monitoring and management of the reservoir.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"178 - 188"},"PeriodicalIF":1.4,"publicationDate":"2023-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49312503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Assessment of water quality for suitability and human health risk: a study of the Owan River, Edo State, Nigeria","authors":"N. Egun, I. Oboh","doi":"10.2989/16085914.2022.2156468","DOIUrl":"https://doi.org/10.2989/16085914.2022.2156468","url":null,"abstract":"Suitability assessment of water bodies for human consumption and its implication on human health is critical to water resources utilisation and sustainable development. This study investigated the water quality of the Owan River and the potential health risk to users. Examined physico-chemical parameters were within the Nigerian National Environmental Standards and Regulation Enforcement Agency permissible limits, except for the lead concentration. Water quality index values (Water Quality Index: 84.50–316.20) indicated that surface water from the sampling locations were of poor quality and unsuitable for drinking (Water Quality Index: > 50). The comprehensive pollution index values (Comprehensive Pollution Index: 0.31–0.57) indicate the water is sub–clean to slightly polluted. Evaluated non–carcinogenic risk to human health showed that children in the receptor population were predisposed to risk from heavy metals through oral ingestion (Oral Hazard Index: > 1), while the water was safe for dermal contact (Dermal Hazard Index: < 1) for adults and children. Integrated carcinogenic risk values classified the surface water as Grade IV (Medium risk), with cadmium having the highest carcinogenic risk. Cadmium accounted for approximately 94% of the total carcinogenic risk and hence a concern for public health. Natural runoff and anthropogenic activities were identified as sources of pollutants within the watershed. The study has provided data for water resource quality monitoring and public health management.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"19 - 27"},"PeriodicalIF":1.4,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44597985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Colonisation theory and invasive biota: the Great Fish River case history, 35 years later","authors":"Pule P Mpopetsi, Wilbert T. Kadye","doi":"10.2989/16085914.2022.2142508","DOIUrl":"https://doi.org/10.2989/16085914.2022.2142508","url":null,"abstract":"Using the Great Fish River, South Africa, Laurenson and Hocutt (1986) proposed a colonisation theory outlining the characteristics of successful invaders and the properties of aquatic habitats that facilitate successful fish invasions. The Great Fish River has modified flow due to an inter-basin water transfer (IBWT). The present study evaluated the current state of invasions and probable mechanisms facilitating establishment of non-native fishes within this river. We used historical literature on the non-native fishes and associated this information with the recent distribution records of these fishes within this system. We hypothesised that non-native fishes would reflect life-history traits and environmental associations that were consistent with adaptability to flow-modified disturbance. Of the 11 non-native fish species recorded within this system, seven have established, three have failed to establish and one is uncertain. The Orange–Fish IBWT and angling were the main vectors of invasions, accounting for 36% and 46% of the non-native species, respectively. Life-history traits, such as large size, greater longevity and wide habitat tolerance, appear to have facilitated establishment of most species. Our findings indicate that both intrinsic and extrinsic factors may explain the invasions of non-native fishes within the Great Fish River and possibly other similarly disturbed systems.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"84 - 96"},"PeriodicalIF":1.4,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48935600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. N. Odume, F. Akamagwuna, Pindiwe Ntloko, H. Dallas, C. F. Nnadozie, H. Barber-James
{"title":"A trait database for southern African freshwater invertebrates","authors":"O. N. Odume, F. Akamagwuna, Pindiwe Ntloko, H. Dallas, C. F. Nnadozie, H. Barber-James","doi":"10.2989/16085914.2022.2142505","DOIUrl":"https://doi.org/10.2989/16085914.2022.2142505","url":null,"abstract":"Invertebrates are often used as indicators of ecosystem health. In community ecology, the use of organism traits (e.g. behavioural, biological or ecological) can be of value in relation to impact diagnosis and assemblage prediction. It has also been recognised that certain traits are related to ecosystem function, and their use in biological monitoring provide insights into ecosystem functional responses to stressors. However, the paucity of trait information and non-availability of a local trait database for southern African invertebrates impede progress in using this approach for biological monitoring. To address this critical gap, we compiled an updateable trait database for southern African freshwater invertebrates. The database contains information on 40 trait categories and 204 trait attribute/modalities. Of the 40 trait categories included in the database, 12 are biological, 12 are behavioural, and 16 are ecological preferences. The database is designed to accommodate taxonomic flexibility. In this regard, trait information is entered at multiple taxonomic levels: family, genus, and species, allowing researchers working at different taxonomic resolutions to retrieve relevant information. While there are still gaps in the database, this effort represents the first attempt to synthesise available trait information on southern African freshwater invertebrates.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"64 - 70"},"PeriodicalIF":1.4,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42718033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A comparison of the water quality and plankton diversity of the Okamini Stream to the freshwater systems within the New Calabar River catchment, Port Harcourt, Nigeria","authors":"BB Otene, I. Thornhill, J. Amadi","doi":"10.2989/16085914.2022.2155102","DOIUrl":"https://doi.org/10.2989/16085914.2022.2155102","url":null,"abstract":"The water quality and phytoplankton diversity of the Okamini Stream, Port Harcourt, Nigeria was studied between April and June 2018 at three stations. The data was used to assess the health of the system for supporting local communities. Compared to national and international standards, the stream was found to be acidic, but pH levels (5.87 ± 0.40) were similar to other systems in the New Calabar River catchment. Analysis of variance showed that there was no significant variation (p < 0.05) in water quality between the stations, with the exception of PO4 (0.82 ± 0.40 mg l-1), which was significantly higher than other local systems. A total of 26 species of plankton were recorded during the study. These species belonged to the Bacillariophyceae (n = 10), Chlorophyceae (n = 6), Cyanophyceae (n = 5), Euglenoidea (n = 3), and Chrysophyceae (n = 2), but phytoplankton density was low. The most frequently occurring phytoplankton species were indicators of organic pollution, such as Cyclotella comta, while Melosira varians was recorded at all sampling occasions. Relatively high diversity indices indicated a stable environment. We conclude that the Okamini Stream is not yet degraded, but that the water quality should be monitored, and anthropogenic activities managed to avoid potential future deterioration.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"48 1","pages":"97 - 104"},"PeriodicalIF":1.4,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46630409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}