Monitoring of invertebrate and fish recovery following river rehabilitation using rotenone in the Rondegat River
- Weyl, Olaf L F, Barrow, S, Bellingan, Terence A, Dalu, Tatenda, Ellender, Bruce R, Esler, K, Impson, D, Gouws, Jeanne, Jordaan, M, Villet, Martin H, Wasserman, Ryan J, Woodford, Darragh J
- Authors: Weyl, Olaf L F , Barrow, S , Bellingan, Terence A , Dalu, Tatenda , Ellender, Bruce R , Esler, K , Impson, D , Gouws, Jeanne , Jordaan, M , Villet, Martin H , Wasserman, Ryan J , Woodford, Darragh J
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442411 , vital:73982 , https://www.wrc.org.za/wp-content/uploads/mdocs/2261.pdf
- Description: Fish invasions have been cited as a primary threat to imperilled South African fishes and other aquatic fauna. As a result, the management and control of alien invasive species is a legislated priority in South Africa. From a river rehabilitation perspective, eradicating alien fish allows for the rehabilitation of several kilometres of river, with very significant benefits for the endangered fish species present and for the associated aquatic biota. In South Africa, the piscicide rotenone is one of the preferred methods for achieving eradication.
- Full Text:
- Date Issued: 2016
- Authors: Weyl, Olaf L F , Barrow, S , Bellingan, Terence A , Dalu, Tatenda , Ellender, Bruce R , Esler, K , Impson, D , Gouws, Jeanne , Jordaan, M , Villet, Martin H , Wasserman, Ryan J , Woodford, Darragh J
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442411 , vital:73982 , https://www.wrc.org.za/wp-content/uploads/mdocs/2261.pdf
- Description: Fish invasions have been cited as a primary threat to imperilled South African fishes and other aquatic fauna. As a result, the management and control of alien invasive species is a legislated priority in South Africa. From a river rehabilitation perspective, eradicating alien fish allows for the rehabilitation of several kilometres of river, with very significant benefits for the endangered fish species present and for the associated aquatic biota. In South Africa, the piscicide rotenone is one of the preferred methods for achieving eradication.
- Full Text:
- Date Issued: 2016
Rapid bioassessment of the effects of repeated rotenone treatments on invertebrate assemblages in the Rondegat River, South Africa
- Bellingan, Terence A, Woodford, Darragh J, Gouws, Jeanne, Villet, Martin H, Weyl, Olaf L F
- Authors: Bellingan, Terence A , Woodford, Darragh J , Gouws, Jeanne , Villet, Martin H , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442279 , vital:73972 , https://doi.org/10.2989/16085914.2014.984651
- Description: The potential collateral effects of eradicating invasive fishes in streams necessitate the monitoring of invertebrate communities during treatment. In an environmental rehabilitation programme, non-native smallmouth bass were removed from the lower reaches of the Rondegat River, Western Cape, South Africa, in 2012 and again in 2013 using the piscicide rotenone. A monitoring programme tracked the ecological response of organisms to these activities using quantitative sampling of macroinvertebrates on stones and the ISO-certified SASS5 rapid bioassessment method for assessing macroinvertebrate community integrity. We recorded a significant decrease in macroinvertebrate densities from the stones-in-current biotope following both rotenone treatments. The average score per taxon (ASPT) declined after the first treatment, indicating a loss of taxa sensitive to diminished water quality, then recovered prior to the second treatment, and subsequently no decline was detected after the lower dose used in the 2013 treatment. The SASS values were too variable to reveal trends. The ASPTs indicated that the community may have been resistant to low dose and resilient to high dose, due to inter-treatment recovery following the 2012 treatment, suggesting that the invertebrate assemblage is resilient to the conservative use of rotenone for localised river rehabilitation when upstream sources of recruitment exist.
- Full Text:
- Date Issued: 2015
- Authors: Bellingan, Terence A , Woodford, Darragh J , Gouws, Jeanne , Villet, Martin H , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442279 , vital:73972 , https://doi.org/10.2989/16085914.2014.984651
- Description: The potential collateral effects of eradicating invasive fishes in streams necessitate the monitoring of invertebrate communities during treatment. In an environmental rehabilitation programme, non-native smallmouth bass were removed from the lower reaches of the Rondegat River, Western Cape, South Africa, in 2012 and again in 2013 using the piscicide rotenone. A monitoring programme tracked the ecological response of organisms to these activities using quantitative sampling of macroinvertebrates on stones and the ISO-certified SASS5 rapid bioassessment method for assessing macroinvertebrate community integrity. We recorded a significant decrease in macroinvertebrate densities from the stones-in-current biotope following both rotenone treatments. The average score per taxon (ASPT) declined after the first treatment, indicating a loss of taxa sensitive to diminished water quality, then recovered prior to the second treatment, and subsequently no decline was detected after the lower dose used in the 2013 treatment. The SASS values were too variable to reveal trends. The ASPTs indicated that the community may have been resistant to low dose and resilient to high dose, due to inter-treatment recovery following the 2012 treatment, suggesting that the invertebrate assemblage is resilient to the conservative use of rotenone for localised river rehabilitation when upstream sources of recruitment exist.
- Full Text:
- Date Issued: 2015
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