Movement behaviour of largemouth bass Micropterus salmoides in a South African impoundment
- Howell, Dylan H, Cowley, Paul D, Childs, Amber-Robyn, Weyl, Olaf L F
- Authors: Howell, Dylan H , Cowley, Paul D , Childs, Amber-Robyn , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443893 , vital:74169 , https://doi.org/10.1080/15627020.2015.1040837
- Description: The objectives of this study were to describe movements and area use patterns of largemouth bass Micropterus salmoides in relation to abiotic factors (water temperature, river inflow and water level). The study was conducted in the Kubusi arm of Wriggleswade Dam, Eastern Cape, South Africa where nine largemouth bass (310–385 mm FL) were surgically implanted with individually coded acoustic transmitters and monitored for nine months (May 2010 to January 2011) using an array of five moored acoustic data-logging receivers. The daily position occupied by largemouth bass was significantly affected by water temperature (P0.001) and river inflow (P0.001), whereas water level had no effect. Largemouth bass spent little or no time in the shallow river inlet areas when water temperature was 12.5 °C, but as water temperature increased, their utilisation of shallow areas increased significantly. The results from this study demonstrate the importance of environmental factors, particularly water temperature, on the movement of largemouth bass.
- Full Text:
- Date Issued: 2015
- Authors: Howell, Dylan H , Cowley, Paul D , Childs, Amber-Robyn , Weyl, Olaf L F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443893 , vital:74169 , https://doi.org/10.1080/15627020.2015.1040837
- Description: The objectives of this study were to describe movements and area use patterns of largemouth bass Micropterus salmoides in relation to abiotic factors (water temperature, river inflow and water level). The study was conducted in the Kubusi arm of Wriggleswade Dam, Eastern Cape, South Africa where nine largemouth bass (310–385 mm FL) were surgically implanted with individually coded acoustic transmitters and monitored for nine months (May 2010 to January 2011) using an array of five moored acoustic data-logging receivers. The daily position occupied by largemouth bass was significantly affected by water temperature (P0.001) and river inflow (P0.001), whereas water level had no effect. Largemouth bass spent little or no time in the shallow river inlet areas when water temperature was 12.5 °C, but as water temperature increased, their utilisation of shallow areas increased significantly. The results from this study demonstrate the importance of environmental factors, particularly water temperature, on the movement of largemouth bass.
- Full Text:
- Date Issued: 2015
Juvenile population dynamics of Oreochromis mossambicus in an intermittently open estuary at the limit of its natural distribution
- Ellender, Bruce R, Weyl, Olaf L F, Shanyengange, M K, Cowley, Paul D
- Authors: Ellender, Bruce R , Weyl, Olaf L F , Shanyengange, M K , Cowley, Paul D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446893 , vital:74568 , https://doi.org/10.1080/15627020.2008.11657245
- Description: Juvenile Oreochromis mossambicus in the 25 ha, temperate, intermittently open, East Kleinemonde Estuary in the Eastern Cape, South Africa (33°32’S, 27°03’E), showed a seasonal shift in distribution, occupying all areas of the estuary in summer and, subsequently, being limited to the upper reaches in winter. The young of the year in the littoral zone were rapidly depleted and resultant estimates of the instantaneous rate of total mortality (Z) ranged from 5.4/yr to 6.9/yr. High annual rates of juvenile mortality and small adult populations imply that stock recovery after a reduction in adult population numbers, through activities such as fishing, may be slow. This work adds to the knowledge base of O. mossambicus ecology and population dynamics in temperate estuaries at the limit of its natural distribution.
- Full Text:
- Date Issued: 2008
- Authors: Ellender, Bruce R , Weyl, Olaf L F , Shanyengange, M K , Cowley, Paul D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446893 , vital:74568 , https://doi.org/10.1080/15627020.2008.11657245
- Description: Juvenile Oreochromis mossambicus in the 25 ha, temperate, intermittently open, East Kleinemonde Estuary in the Eastern Cape, South Africa (33°32’S, 27°03’E), showed a seasonal shift in distribution, occupying all areas of the estuary in summer and, subsequently, being limited to the upper reaches in winter. The young of the year in the littoral zone were rapidly depleted and resultant estimates of the instantaneous rate of total mortality (Z) ranged from 5.4/yr to 6.9/yr. High annual rates of juvenile mortality and small adult populations imply that stock recovery after a reduction in adult population numbers, through activities such as fishing, may be slow. This work adds to the knowledge base of O. mossambicus ecology and population dynamics in temperate estuaries at the limit of its natural distribution.
- Full Text:
- Date Issued: 2008
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