Pub Date : 2021-06-03DOI: 10.2989/16085914.2021.1898927
M. Omoigberale, I. Ezenwa, E. Biose, C. Okoye
The impact of a rubber effluent on the water quality of Oken River, Nigeria, was assessed. Surface water was analysed for water quality parameters at four sites; one upstream and three downstream. Significantly raised (p ≤ 0.05) levels of electrical conductivity, salinity, colour, turbidity, TSS, TDS, DO, COD, HCO3 -, Ca, Cl, P, Mn, Cu, Pb and THC at the site immediately downstream of the pollution point source were recorded, with levels of colour, turbidity, Cd and Ni in all the stations higher than the WHO permissible limits. Principal component analysis (PCA) yielded 28 variables under six components that accounted for 92.33% of the total variance between sites. The PCA and water quality index (WQI) revealed significant influence by anthropogenic activities on the water quality of the river. Furthermore, the WQI output showed that the river water was not fit for human consumption. The cluster analysis revealed similarity in the physico-chemical conditions at Stations 1 and 4, whereas Stations 1 and 2 were the most dissimilar. This study advocates monitoring and protection of water bodies upstream and downstream of the influx of untreated effluents.
{"title":"The impact of rubber effluent discharges on the water quality of a tropical rain forest river in Nigeria","authors":"M. Omoigberale, I. Ezenwa, E. Biose, C. Okoye","doi":"10.2989/16085914.2021.1898927","DOIUrl":"https://doi.org/10.2989/16085914.2021.1898927","url":null,"abstract":"The impact of a rubber effluent on the water quality of Oken River, Nigeria, was assessed. Surface water was analysed for water quality parameters at four sites; one upstream and three downstream. Significantly raised (p ≤ 0.05) levels of electrical conductivity, salinity, colour, turbidity, TSS, TDS, DO, COD, HCO3 -, Ca, Cl, P, Mn, Cu, Pb and THC at the site immediately downstream of the pollution point source were recorded, with levels of colour, turbidity, Cd and Ni in all the stations higher than the WHO permissible limits. Principal component analysis (PCA) yielded 28 variables under six components that accounted for 92.33% of the total variance between sites. The PCA and water quality index (WQI) revealed significant influence by anthropogenic activities on the water quality of the river. Furthermore, the WQI output showed that the river water was not fit for human consumption. The cluster analysis revealed similarity in the physico-chemical conditions at Stations 1 and 4, whereas Stations 1 and 2 were the most dissimilar. This study advocates monitoring and protection of water bodies upstream and downstream of the influx of untreated effluents.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"390 - 401"},"PeriodicalIF":1.4,"publicationDate":"2021-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44844670","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}
Pub Date : 2021-05-31DOI: 10.2989/16085914.2021.1922349
A. Degsera, M. Minwyelet, T. Yosef
Nile tilapia Oreochromis niloticus is a commercially important fish species in the Lake Tana fishery and contributes to 65% of the total annual catch. This study estimated the maximum sustainable yield (MSY) and effort at maximum sustainable yield (fMSY) for the O. niloticus fishery using the Thompson and Bell yield prediction model. Catch and effort data from four representative landing sites were collected daily from June 2016 to May 2017 and used to estimate the total mortality coefficient (Z) using catch curve analysis, natural mortality (M) using Pauly’s empirical formula, and fishing mortality (F) as F = Z − M. Population abundance was evaluated using the Jones length-based cohort analysis model. The estimated Z, M and F values were 1.1, 0.52, and 0.49 per year, respectively. In total, 5 077 tons of O. niloticus were produced, which exceeds the MSY of 4 904 tons per year that could be obtained from the fishery at an F0.1. Consequently, the recommendation is to reduce the fishing effort by 15%. Collection of catch-and- effort data from more landing sites, over an extended period, could improve the yield estimates and this should be considered in conjunction with a bioeconomic analysis in future.
{"title":"Stock assessment of Nile tilapia Oreochromis niloticus (Linnaeus 1758) in Lake Tana, Ethiopia","authors":"A. Degsera, M. Minwyelet, T. Yosef","doi":"10.2989/16085914.2021.1922349","DOIUrl":"https://doi.org/10.2989/16085914.2021.1922349","url":null,"abstract":"Nile tilapia Oreochromis niloticus is a commercially important fish species in the Lake Tana fishery and contributes to 65% of the total annual catch. This study estimated the maximum sustainable yield (MSY) and effort at maximum sustainable yield (fMSY) for the O. niloticus fishery using the Thompson and Bell yield prediction model. Catch and effort data from four representative landing sites were collected daily from June 2016 to May 2017 and used to estimate the total mortality coefficient (Z) using catch curve analysis, natural mortality (M) using Pauly’s empirical formula, and fishing mortality (F) as F = Z − M. Population abundance was evaluated using the Jones length-based cohort analysis model. The estimated Z, M and F values were 1.1, 0.52, and 0.49 per year, respectively. In total, 5 077 tons of O. niloticus were produced, which exceeds the MSY of 4 904 tons per year that could be obtained from the fishery at an F0.1. Consequently, the recommendation is to reduce the fishing effort by 15%. Collection of catch-and- effort data from more landing sites, over an extended period, could improve the yield estimates and this should be considered in conjunction with a bioeconomic analysis in future.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"499 - 507"},"PeriodicalIF":1.4,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44617221","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}
Pub Date : 2021-05-31DOI: 10.2989/16085914.2021.1911780
P. Ogungbile, P. Ayeku, A. Ajibare
The biotolerance of water spinach (Ipomoea aquatica) to heavy metals was investigated in the Agodi Reservoir and its supplying source, the Ogunpa River, to examine the impact of aquatic pollution. I. aquatica was collected monthly from the Ogunpa River and the Agodi Reservoir. Atomic absorption spectrophotometry was used to analyse the concentration of heavy metals in the samples. A box plot was used to evaluate the tolerance of the plants to heavy metals and ecological risk quotients (ERQ) were calculated to indicate the threat to human health and environment. The concentrations of cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in the plants were below standard thresholds, but cadmium (Cd), iron (Fe), manganese (Mn) and lead (Pb) were present in higher than permissible levels. The ERQ of Cd in I. aquatica in the Ogunpa River was at an elevated ecological risk level in January (3.450), May (3.125), June (8.175), August (1.900) and September (2.025). The ERQ of Co, Cr, Cu and Ni in plants from both the reservoir and the river were less than one. The ERQ and biotolerance of heavy metals in this study indicated that I. aquatica is effective in binding heavy metals.
{"title":"Comparative biotolerance of water spinach, Ipomoea aquatica, to heavy metal pollution in the Agodi Reservoir and the Ogunpa River, Oyo State, Nigeria","authors":"P. Ogungbile, P. Ayeku, A. Ajibare","doi":"10.2989/16085914.2021.1911780","DOIUrl":"https://doi.org/10.2989/16085914.2021.1911780","url":null,"abstract":"The biotolerance of water spinach (Ipomoea aquatica) to heavy metals was investigated in the Agodi Reservoir and its supplying source, the Ogunpa River, to examine the impact of aquatic pollution. I. aquatica was collected monthly from the Ogunpa River and the Agodi Reservoir. Atomic absorption spectrophotometry was used to analyse the concentration of heavy metals in the samples. A box plot was used to evaluate the tolerance of the plants to heavy metals and ecological risk quotients (ERQ) were calculated to indicate the threat to human health and environment. The concentrations of cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in the plants were below standard thresholds, but cadmium (Cd), iron (Fe), manganese (Mn) and lead (Pb) were present in higher than permissible levels. The ERQ of Cd in I. aquatica in the Ogunpa River was at an elevated ecological risk level in January (3.450), May (3.125), June (8.175), August (1.900) and September (2.025). The ERQ of Co, Cr, Cu and Ni in plants from both the reservoir and the river were less than one. The ERQ and biotolerance of heavy metals in this study indicated that I. aquatica is effective in binding heavy metals.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"492 - 498"},"PeriodicalIF":1.4,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49470778","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}
Pub Date : 2021-05-14DOI: 10.2989/16085914.2021.1884523
E. I. Abdel-Aal
The El-Ibrahimia Canal is one of the main irrigation sources in Egypt, that it supplies perennial irrigation to approximately 600 000 ha (one-fourth of the Egyptian cultivated land). An annual study on species composition of microalgae attached to the submerged hydrophyte Myriophyllum spicatum L. was carried out from midautumn 2016 to midsummer 2017. Epiphytic microalgae were represented by 109 species related to 66 genera. Diatoms were the most abundant group (66–95%) followed by green algae (3.3–25%). Aulacoseira granulata, Cyclotella ocellata, Cymbella affinis, Gomphonema parvulum, Navicula cuspidata, Navicula muralis, Nitzschia dissipata, Nitzschia hungerica, Staurosirella leptostauron, and Ulnaria ulna were the most dominant species. Regarding morphology-based functional groups (MBFGs) taxonomic approach, the epiphytic microalgae species were represented by six MBFGs (I, III, IV, V, VI and VII). The MBFG VI (mainly diatoms) was the leading group with a minimum average percentage of 59.9% during the summer season and a maximum of 95.06% during the winter season. The mean annual values of cell density fluctuated greatly between 8.6 × 106 (during the spring season) and 4.7 × 107 cells g−1 plant wet weight (during winter season). The changes in microalgae biovolumes have the same trend as cell density, with mean seasonal values of 3.89 × 109, 2.56 × 1010, 1.16 × 109, and 3.21 × 109 µm3 g−1 plant wet weight during autumn, winter, spring and summer seasons, respectively. Diversity index values ranged between 2.0 and 3.0, revealing a light pollution status of the canal. In general, the species composition and diversity of epiphytic algae along the El-Ibrahimia Canal are highly dependent on site and the physico-chemical properties of canal water affected by agricultural practice around it.
{"title":"Species composition and diversity of epiphytic microalgae on Myriophyllum spicatum in the El-Ibrahimia Canal, Egypt","authors":"E. I. Abdel-Aal","doi":"10.2989/16085914.2021.1884523","DOIUrl":"https://doi.org/10.2989/16085914.2021.1884523","url":null,"abstract":"The El-Ibrahimia Canal is one of the main irrigation sources in Egypt, that it supplies perennial irrigation to approximately 600 000 ha (one-fourth of the Egyptian cultivated land). An annual study on species composition of microalgae attached to the submerged hydrophyte Myriophyllum spicatum L. was carried out from midautumn 2016 to midsummer 2017. Epiphytic microalgae were represented by 109 species related to 66 genera. Diatoms were the most abundant group (66–95%) followed by green algae (3.3–25%). Aulacoseira granulata, Cyclotella ocellata, Cymbella affinis, Gomphonema parvulum, Navicula cuspidata, Navicula muralis, Nitzschia dissipata, Nitzschia hungerica, Staurosirella leptostauron, and Ulnaria ulna were the most dominant species. Regarding morphology-based functional groups (MBFGs) taxonomic approach, the epiphytic microalgae species were represented by six MBFGs (I, III, IV, V, VI and VII). The MBFG VI (mainly diatoms) was the leading group with a minimum average percentage of 59.9% during the summer season and a maximum of 95.06% during the winter season. The mean annual values of cell density fluctuated greatly between 8.6 × 106 (during the spring season) and 4.7 × 107 cells g−1 plant wet weight (during winter season). The changes in microalgae biovolumes have the same trend as cell density, with mean seasonal values of 3.89 × 109, 2.56 × 1010, 1.16 × 109, and 3.21 × 109 µm3 g−1 plant wet weight during autumn, winter, spring and summer seasons, respectively. Diversity index values ranged between 2.0 and 3.0, revealing a light pollution status of the canal. In general, the species composition and diversity of epiphytic algae along the El-Ibrahimia Canal are highly dependent on site and the physico-chemical properties of canal water affected by agricultural practice around it.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"319 - 328"},"PeriodicalIF":1.4,"publicationDate":"2021-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46369454","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}
Pub Date : 2021-05-09DOI: 10.2989/16085914.2021.1890541
P. Opute, I. Oboh, JE Asouzu, N. Pilani, E. Mbajiorgu
Aquatic ecosystems often receive a wide spectrum of pollutants introduced directly or indirectly. The herbicide atrazine, an endocrine disrupting chemical (EDC), frequently contaminates potable water supplies and aquatic ecosystems. Studies suggest atrazine induced alterations in the neuroendocrine system along the hypothalamus-pituitary-gonadal (HPG) axis. This study investigated the effects of atrazine (0, 2.5, 25, 250 and 500 μg l−1 for 28 days of exposure) on testosterone (TST) and prolactin (PRL) levels, testes histology and seminiferous tubular morphometry of Clarias gariepinus juveniles. TST and PRL significantly decreased in all the 28 days atrazine exposed groups. Histologically, the testes showed vacuolated and sloughing of basal germinal epithelium in the treated groups. A high correlation between testicular biopsy score counts and results of seminiferous tubular morphometry was also observed. Findings from this study confirm that atrazine is an EDC in fish that alters reproductive dysfunction by targeting the HPG axis, as evidenced by its effects on the investigated reproductive hormones. Furthermore, atrazine disrupted the histoarchitectural components of the testes, which may interfere with spermatogenesis and therefore impair the reproductive functions of the fish.
{"title":"Effects of atrazine on the endocrinology and histoarchitecture of the testes in African Catfish, Clarias gariepinus (Burchell, 1822)","authors":"P. Opute, I. Oboh, JE Asouzu, N. Pilani, E. Mbajiorgu","doi":"10.2989/16085914.2021.1890541","DOIUrl":"https://doi.org/10.2989/16085914.2021.1890541","url":null,"abstract":"Aquatic ecosystems often receive a wide spectrum of pollutants introduced directly or indirectly. The herbicide atrazine, an endocrine disrupting chemical (EDC), frequently contaminates potable water supplies and aquatic ecosystems. Studies suggest atrazine induced alterations in the neuroendocrine system along the hypothalamus-pituitary-gonadal (HPG) axis. This study investigated the effects of atrazine (0, 2.5, 25, 250 and 500 μg l−1 for 28 days of exposure) on testosterone (TST) and prolactin (PRL) levels, testes histology and seminiferous tubular morphometry of Clarias gariepinus juveniles. TST and PRL significantly decreased in all the 28 days atrazine exposed groups. Histologically, the testes showed vacuolated and sloughing of basal germinal epithelium in the treated groups. A high correlation between testicular biopsy score counts and results of seminiferous tubular morphometry was also observed. Findings from this study confirm that atrazine is an EDC in fish that alters reproductive dysfunction by targeting the HPG axis, as evidenced by its effects on the investigated reproductive hormones. Furthermore, atrazine disrupted the histoarchitectural components of the testes, which may interfere with spermatogenesis and therefore impair the reproductive functions of the fish.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"361 - 369"},"PeriodicalIF":1.4,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42643045","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}
Pub Date : 2021-05-06DOI: 10.2989/16085914.2021.1888688
Shymaa S Zaher, W. Aly
Lake Nasser is a reservoir of freshwater for drinking and irrigation in Egypt and it constitutes an important share in the fisheries sector. This study aims to acquire a better understanding of the status of phytoplankton distribution in Lake Nasser under the current flood regime and before the construction of the Grand Ethiopian Renaissance Dam (GERD). Samples were collected from fifteen sites representing different lake sectors along the main channel of the lake during 2016−2017. Approximately 103 species were recorded, belonging to six different classes, dominated by Cyanobacteria, Bacillariophyceae, Chlorophyceae, whereas Euglenophyceae, Dinophyceae and Chrysophyceae were rare. Based on the abundance of phytoplankton species, the pre-flood and post-flood seasons were very well discriminated. A major blooming of Cyanobacteria in the Tushka sector was detected during the pre-flood season, whereas this phenomenon diminished in the post-flood period when Bacillariophyceae and Chlorophyceae appeared. The results of this study indicated that the most important factors affecting phytoplankton species distribution during pre-flood and post-flood seasons are temperature, nutrients and total dissolved solids. The study confirms that flood regime substantially affects the phytoplankton abundance and distribution in Lake Nasser.
{"title":"Impact of flood regime on phytoplankton communities in the large African reservoir, Lake Nasser, Egypt","authors":"Shymaa S Zaher, W. Aly","doi":"10.2989/16085914.2021.1888688","DOIUrl":"https://doi.org/10.2989/16085914.2021.1888688","url":null,"abstract":"Lake Nasser is a reservoir of freshwater for drinking and irrigation in Egypt and it constitutes an important share in the fisheries sector. This study aims to acquire a better understanding of the status of phytoplankton distribution in Lake Nasser under the current flood regime and before the construction of the Grand Ethiopian Renaissance Dam (GERD). Samples were collected from fifteen sites representing different lake sectors along the main channel of the lake during 2016−2017. Approximately 103 species were recorded, belonging to six different classes, dominated by Cyanobacteria, Bacillariophyceae, Chlorophyceae, whereas Euglenophyceae, Dinophyceae and Chrysophyceae were rare. Based on the abundance of phytoplankton species, the pre-flood and post-flood seasons were very well discriminated. A major blooming of Cyanobacteria in the Tushka sector was detected during the pre-flood season, whereas this phenomenon diminished in the post-flood period when Bacillariophyceae and Chlorophyceae appeared. The results of this study indicated that the most important factors affecting phytoplankton species distribution during pre-flood and post-flood seasons are temperature, nutrients and total dissolved solids. The study confirms that flood regime substantially affects the phytoplankton abundance and distribution in Lake Nasser.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"340 - 352"},"PeriodicalIF":1.4,"publicationDate":"2021-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43544957","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}
Pub Date : 2021-05-03DOI: 10.2989/16085914.2021.1882931
M. Gondwe, Michael Murray-Hudson, N. Mazrui, O. Moses, E. Mosimanyana, O. Mogobe
Water quantity and quality are important aspects in the management of aquatic ecosystems, including wetlands. This paper has integrated available knowledge from literature on the limnology of the Okavango Delta, Botswana. The current near-natural solute concentrations in the inflow waters can be attributed to low chemical weathering of the quartz basin substrate and nearly absent anthropogenic nutrient sources within the Okavango Delta. The concentration of solutes in endorheic ecosystems is a natural phenomenon. In the Okavango Delta, this concentration is offset by the accumulation of solutes in groundwater beneath numerous treed-islands, due to evapotranspiration by evergreen trees. The freshwater environment has fostered high abundance and diversity of flora and fauna in a semi-arid environment. However, there are several aspects of the Okavango Delta that need more rigorous researched for management purposes. Some of the important knowledge gaps include the role of atmospheric deposition and animal excretion as sources of nutrients and trace elements into the system, and the influence of hydro-period on the distribution of trace elements especially in floodplain sediments, flora and fauna across the Okavango Delta. The issue of bioaccumulation of trace elements is also an important knowledge gap for the Okavango Delta particularly for wildlife and human health.
{"title":"A review of the limnology of the Okavango Delta, Botswana","authors":"M. Gondwe, Michael Murray-Hudson, N. Mazrui, O. Moses, E. Mosimanyana, O. Mogobe","doi":"10.2989/16085914.2021.1882931","DOIUrl":"https://doi.org/10.2989/16085914.2021.1882931","url":null,"abstract":"Water quantity and quality are important aspects in the management of aquatic ecosystems, including wetlands. This paper has integrated available knowledge from literature on the limnology of the Okavango Delta, Botswana. The current near-natural solute concentrations in the inflow waters can be attributed to low chemical weathering of the quartz basin substrate and nearly absent anthropogenic nutrient sources within the Okavango Delta. The concentration of solutes in endorheic ecosystems is a natural phenomenon. In the Okavango Delta, this concentration is offset by the accumulation of solutes in groundwater beneath numerous treed-islands, due to evapotranspiration by evergreen trees. The freshwater environment has fostered high abundance and diversity of flora and fauna in a semi-arid environment. However, there are several aspects of the Okavango Delta that need more rigorous researched for management purposes. Some of the important knowledge gaps include the role of atmospheric deposition and animal excretion as sources of nutrients and trace elements into the system, and the influence of hydro-period on the distribution of trace elements especially in floodplain sediments, flora and fauna across the Okavango Delta. The issue of bioaccumulation of trace elements is also an important knowledge gap for the Okavango Delta particularly for wildlife and human health.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"251 - 273"},"PeriodicalIF":1.4,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43156849","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}
Pub Date : 2021-04-28DOI: 10.2989/16085914.2021.1894085
N. Khumalo, S. Mdluli, J. Lebepe
Extreme floods have become frequent in the urban Palmiet River due to exacerbating climate change. Therefore, the current study aimed to explore a short-term recovery of macroinvertebrate communities following a flash flood in the Palmiet River, KwaZulu-Natal, South Africa. Different biotopes, i.e. stones, gravel sand and mud, and vegetation were sampled after the March-April heavy rain in 2018. Ephemeroptera, Odonatan, and Hemipteran have shown similar trends across weeks at all sites. Plecoptera and Coleoptera started recovering at week four However, the total abundance and taxa richness had significantly recovered during the fourth week at site 2 and 3, and fifth week at site 1. Communities have shown no significant difference for each site from weeks six to eight (ANOVA, p > 0.5), which implies that climax on macroinvertebrate communities was reached at week six. Hydrologic regime change has not influenced water quality parameters across all weeks (ANOVA, p > 0.5) and this was also reflected on the average score per taxon (ASPT), which has shown no significant difference (ANOVA, p > 0.5) across weeks at all sites. These findings provide a baseline for future studies on flood effect on urban streams and supplement the understanding of the effects of sudden hydrologic regime changes on macroinvertebrate communities.
{"title":"Short-term recovery of macroinvertebrate communities following a flash flood in an urban river: a case study of the Palmiet River in Durban, South Africa","authors":"N. Khumalo, S. Mdluli, J. Lebepe","doi":"10.2989/16085914.2021.1894085","DOIUrl":"https://doi.org/10.2989/16085914.2021.1894085","url":null,"abstract":"Extreme floods have become frequent in the urban Palmiet River due to exacerbating climate change. Therefore, the current study aimed to explore a short-term recovery of macroinvertebrate communities following a flash flood in the Palmiet River, KwaZulu-Natal, South Africa. Different biotopes, i.e. stones, gravel sand and mud, and vegetation were sampled after the March-April heavy rain in 2018. Ephemeroptera, Odonatan, and Hemipteran have shown similar trends across weeks at all sites. Plecoptera and Coleoptera started recovering at week four However, the total abundance and taxa richness had significantly recovered during the fourth week at site 2 and 3, and fifth week at site 1. Communities have shown no significant difference for each site from weeks six to eight (ANOVA, p > 0.5), which implies that climax on macroinvertebrate communities was reached at week six. Hydrologic regime change has not influenced water quality parameters across all weeks (ANOVA, p > 0.5) and this was also reflected on the average score per taxon (ASPT), which has shown no significant difference (ANOVA, p > 0.5) across weeks at all sites. These findings provide a baseline for future studies on flood effect on urban streams and supplement the understanding of the effects of sudden hydrologic regime changes on macroinvertebrate communities.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"370 - 376"},"PeriodicalIF":1.4,"publicationDate":"2021-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45651537","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}
Pub Date : 2021-04-28DOI: 10.2989/16085914.2021.1895052
C. Chabet Dis, W. Refes, I. Varó, F. Hontoria, F. Amat, J. Navarro
The aim of this study was to determine the nutritional value of three populations of Artemia, one from the Bethioua Sebkha (Oran) and two new biotopes at El Melah (Bechar) and Timimoune (Adrar), by evaluating the cyst and nauplius biometry, hatching parameters and fatty acid profiles. This information is of relevance to aquaculture initiatives, and fills in knowledge gaps from previous research at Algerian sites. The size of nauplii varied from 453.26 ± 0.3 µm and 478.73 ± 0.2 µm. The chorion thickness was between 13.28 µm and 10.50 µm. The highest hatching percentage and hatching efficiency were obtained after decapsulation of Bethioua cysts. The shortest hatching synchrony time was also found for the Bethioua cysts. All cyst samples from the the Bethioua population analysed in this study showed a freshwater-type fatty acid profile, rich in linolenic acid (LNA, 18:3n.3), opposed to a marine-type fatty acid profile rich in presence of eicosapentaenoic acid (EPA, 20:5n-3). The Bethioua population exhibited the best hatching performance and are ideally suited for use in aquaculture.
{"title":"Quality evaluation of Artemia cysts from three Algerian populations","authors":"C. Chabet Dis, W. Refes, I. Varó, F. Hontoria, F. Amat, J. Navarro","doi":"10.2989/16085914.2021.1895052","DOIUrl":"https://doi.org/10.2989/16085914.2021.1895052","url":null,"abstract":"The aim of this study was to determine the nutritional value of three populations of Artemia, one from the Bethioua Sebkha (Oran) and two new biotopes at El Melah (Bechar) and Timimoune (Adrar), by evaluating the cyst and nauplius biometry, hatching parameters and fatty acid profiles. This information is of relevance to aquaculture initiatives, and fills in knowledge gaps from previous research at Algerian sites. The size of nauplii varied from 453.26 ± 0.3 µm and 478.73 ± 0.2 µm. The chorion thickness was between 13.28 µm and 10.50 µm. The highest hatching percentage and hatching efficiency were obtained after decapsulation of Bethioua cysts. The shortest hatching synchrony time was also found for the Bethioua cysts. All cyst samples from the the Bethioua population analysed in this study showed a freshwater-type fatty acid profile, rich in linolenic acid (LNA, 18:3n.3), opposed to a marine-type fatty acid profile rich in presence of eicosapentaenoic acid (EPA, 20:5n-3). The Bethioua population exhibited the best hatching performance and are ideally suited for use in aquaculture.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"464 - 472"},"PeriodicalIF":1.4,"publicationDate":"2021-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44440197","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}
Pub Date : 2021-04-23DOI: 10.2989/16085914.2021.1882376
D. Khosa, J. South, R. Wasserman, O. Weyl
Habitat complexity plays an important role in structuring species diversity, behaviour and distribution. Furthermore, habitat complexity can mediate the strength of predator-prey interactions through the provision of prey refugia or through enhancing ambush predation. In this study, we use functional responses (FRs) to compare the effect of habitat complexity on resource utilisation between Largemouth Bass Micropterus salmoides and Florida Bass Micropterus floridanus predating upon Mozambique Tilapia Oreochromis mossambicus fry. Treatments for this study were zero and high habitat complexities, with the latter being artificially constructed using plastic strips. Both predator species exhibited a Type II FR in both habitat complexities, with Florida Bass exhibiting significantly higher FR magnitudes, compared with Largemouth Bass under both habitat complexities. Both species experienced dampening of FR magnitudes under high habitat complexity. Florida Bass had persistently lower handling parameters than Largemouth Bass regardless of habitat complexity. While higher habitat complexity may offer prey refugia from Florida Bass, changes in complexity had a negligible effect upon Largemouth Bass predatory efficiency. Measures to enhance natural complexity through system restoration may be a useful conservation measure for endemic fish in rivers invaded by Florida Bass, however, the same mitigation measures may not be as effective for Largemouth Bass.
{"title":"Habitat structure differentially mitigates predation impact of juvenile largemouth bass and Florida bass","authors":"D. Khosa, J. South, R. Wasserman, O. Weyl","doi":"10.2989/16085914.2021.1882376","DOIUrl":"https://doi.org/10.2989/16085914.2021.1882376","url":null,"abstract":"Habitat complexity plays an important role in structuring species diversity, behaviour and distribution. Furthermore, habitat complexity can mediate the strength of predator-prey interactions through the provision of prey refugia or through enhancing ambush predation. In this study, we use functional responses (FRs) to compare the effect of habitat complexity on resource utilisation between Largemouth Bass Micropterus salmoides and Florida Bass Micropterus floridanus predating upon Mozambique Tilapia Oreochromis mossambicus fry. Treatments for this study were zero and high habitat complexities, with the latter being artificially constructed using plastic strips. Both predator species exhibited a Type II FR in both habitat complexities, with Florida Bass exhibiting significantly higher FR magnitudes, compared with Largemouth Bass under both habitat complexities. Both species experienced dampening of FR magnitudes under high habitat complexity. Florida Bass had persistently lower handling parameters than Largemouth Bass regardless of habitat complexity. While higher habitat complexity may offer prey refugia from Florida Bass, changes in complexity had a negligible effect upon Largemouth Bass predatory efficiency. Measures to enhance natural complexity through system restoration may be a useful conservation measure for endemic fish in rivers invaded by Florida Bass, however, the same mitigation measures may not be as effective for Largemouth Bass.","PeriodicalId":7864,"journal":{"name":"African Journal of Aquatic Science","volume":"46 1","pages":"353 - 360"},"PeriodicalIF":1.4,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48106987","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}
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