On the life history of a cyprinid fish, Labeo cylindricus
- Weyl, Olaf L F, Booth, Anthony J
- Authors: Weyl, Olaf L F , Booth, Anthony J
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125408 , vital:35780 , https://doi.10.1023/A:1007543319416
- Description: Fishes of the genus Labeo are widely distributed throughout Africa and consist of at least 80 species which comprise 16.4% of the African cyprinid ichthyofauna (Reid 1985). Most labeo species are also commercially important throughout the African continent, having contributed significantly to various fisheries. Their roe (sensu caviar) is often harvested as an additional bycatch (Skelton et al. 1991). Despite their obvious importance, the few studies that have investigated aspects of their life history have been conducted on the larger commercial species (Lowe 1952, Mulder 1973, Balon et al. 1974, Potgieter 1974, Baird 1976, Tomasson et al. 1984, van Zyl et al. 1995).
- Full Text:
- Date Issued: 1999
- Authors: Weyl, Olaf L F , Booth, Anthony J
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125408 , vital:35780 , https://doi.10.1023/A:1007543319416
- Description: Fishes of the genus Labeo are widely distributed throughout Africa and consist of at least 80 species which comprise 16.4% of the African cyprinid ichthyofauna (Reid 1985). Most labeo species are also commercially important throughout the African continent, having contributed significantly to various fisheries. Their roe (sensu caviar) is often harvested as an additional bycatch (Skelton et al. 1991). Despite their obvious importance, the few studies that have investigated aspects of their life history have been conducted on the larger commercial species (Lowe 1952, Mulder 1973, Balon et al. 1974, Potgieter 1974, Baird 1976, Tomasson et al. 1984, van Zyl et al. 1995).
- Full Text:
- Date Issued: 1999
The biology of Tilapia rendalli and Oreochromis mossambicus (Pisces: Cichlidae) in a subtropical lake in Mozambique
- Weyl, Olaf L F, Hecht, Thomas
- Authors: Weyl, Olaf L F , Hecht, Thomas
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446944 , vital:74572 , https://www.ajol.info/index.php/az/article/view/154744
- Description: This study of age and growth, reproduction and juvenile recruitment of Tilapia rendalli and Oreochromis mossambicus was undertaken in Lake Chicamba, a large, clear subtropical lake in central Mozambique. Sectioned otoliths were used to estimate age. Marginal zone analysis showed that annulus formation occurred during winter, in July and August. Maximum age estimates for T. rendalli and O. mossambicus were 16 and 10 years, respectively. Growth was described by the 3 parameter von Bertalanffy model as Lt= 238.74 (1-e-0,636 (1+ 00905)) mm TL for T. rendalli and Lt= 266.06 (1-e-0 70904 (1+ 0269)) mm TL for O. mossambicus. The length-at-50% maturity (Lm 50) of male T. rendalli was 218 mm total lenglh (TL) and 205 mm TL in females. In O. mossambicus the Lm 50 for males was 251 mm TL and for females 223 mm TL. Both species spawned throughout summer. Lake level was found to have no effect on spawning periodicity although recruitment was flood dependent.
- Full Text:
- Date Issued: 1998
- Authors: Weyl, Olaf L F , Hecht, Thomas
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446944 , vital:74572 , https://www.ajol.info/index.php/az/article/view/154744
- Description: This study of age and growth, reproduction and juvenile recruitment of Tilapia rendalli and Oreochromis mossambicus was undertaken in Lake Chicamba, a large, clear subtropical lake in central Mozambique. Sectioned otoliths were used to estimate age. Marginal zone analysis showed that annulus formation occurred during winter, in July and August. Maximum age estimates for T. rendalli and O. mossambicus were 16 and 10 years, respectively. Growth was described by the 3 parameter von Bertalanffy model as Lt= 238.74 (1-e-0,636 (1+ 00905)) mm TL for T. rendalli and Lt= 266.06 (1-e-0 70904 (1+ 0269)) mm TL for O. mossambicus. The length-at-50% maturity (Lm 50) of male T. rendalli was 218 mm total lenglh (TL) and 205 mm TL in females. In O. mossambicus the Lm 50 for males was 251 mm TL and for females 223 mm TL. Both species spawned throughout summer. Lake level was found to have no effect on spawning periodicity although recruitment was flood dependent.
- Full Text:
- Date Issued: 1998
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