The status and distribution of a newly identified endemic galaxiid in the eastern Cape Fold Ecoregion, of South Africa
- Authors: Chakona, Gamuchirai , Swartz, Ernst R , Chakona, Albert
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453238 , vital:75233 , xlink:href="https://doi.org/10.1002/aqc.2850"
- Description: DNA-based studies have uncovered cryptic species and lineages within almost all freshwater fishes studied thus far from the Cape Fold Ecoregion (CFE) of South Africa. These studies have changed the way the CFE is viewed, as almost all stream fishes that were previously consid-ered to be of low conservation priority, because they were perceived to have broad geographical ranges, con-tain multiple historically isolated lineages, many of which are narrow-range endemics.
- Full Text:
- Date Issued: 2018
The status and distribution of a newly identified endemic galaxiid in the eastern Cape Fold Ecoregion, of South Africa
- Authors: Chakona, Gamuchirai , Swartz, Ernst R , Chakona, Albert
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425492 , vital:72250 , xlink:href="https://doi.org/10.1002/aqc.2850"
- Description: DNA-based studies have uncovered cryptic species and lineages within almost all freshwater fishes studied thus far from the Cape Fold Ecoregion (CFE) of South Africa. These studies have changed the way the CFE is viewed, as almost all stream fishes that were previously consid-ered to be of low conservation priority, because they were perceived to have broad geographical ranges, con-tain multiple historically isolated lineages, many of which are narrow-range endemics.
- Full Text:
- Date Issued: 2018
Deep genetic divergence between geographically isolated populations of the goldie barb (Barbus pallidus) in South Africa: potential taxonomic and conservation implications
- Authors: Chakona, Albert , Malherbe, Willem S , Gouws, Gavin , Swartz, Ernst R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443284 , vital:74105 , https://hdl.handle.net/10520/EJC177698
- Description: Barbus pallidus as it is presently defined has a disjunct distribution that is divided between northern and southern populations in South Africa. Sequence data from the cytochrome b gene region showed two distinct lineages that correspond to these geographically distant areas. Divergence between these two lineages was relatively high (5.5-6.5%) and comparable to typical interspecific divergences found between closely related southern African cyprinid fishes. Based on this deep genetic divergence, we conclude that the northern lineage may represent a previously unrecognised species or may belong to a different, but known species or species complex not associated with 'true' B. pallidus. These findings add to a growing body of evidence that freshwater fish diversity in southern Africa requires major revision.
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- Date Issued: 2015
First Record of an Introduction of the Giant Pangasius, Pangasius sanitwongsei Smith 1931, Into an African River
- Authors: Mäkinen, Tuuli , Weyl, Olaf L F , van der Walt, Kerry-Ann , Swartz, Ernst R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443340 , vital:74109 , https://hdl.handle.net/10520/EJC145782
- Description: A catfish captured in the Breede River (33°56'41.6"S 20°4'45.6"E) in South Africa was identified using morphological and genetic techniques as the giant pangasius, Pangasius sanitwongsei Smith 1931, a new record for South Africa. The wild-caught specimen was a genetic match to juveniles purchased from the pet trade, and most likely originated from a release by an aquarist. Pangasius sanitwongsei is not on the list of fishes currently permitted for import into South Africa, and its presence in the pet trade illustrates the difficulty associated with preventing illegal introductions.
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- Date Issued: 2013
Using a unified invasion framework to characterize Africa’s first loricariid catfish invasion
- Authors: Jones, Roy W , Weyl, Olaf L F , Hill, Martin P , Swartz, Ernst R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418081 , vital:71507 , xlink:href="https://doi.org/10.1007/s10530-013-0438-7"
- Description: This paper presents evidence of establishment of a loricariid population in the Nseleni River in South Africa and uses a unified framework to determine its invasion stage. Specimens were identified morphologically as Pterygioplichthys disjunctivus (Weber 1991), but genetic barcoding results indicated close association with specimens that may have a hybrid history. The species was introduced into South Africa via the pet trade and the first record of introduction into the wild was in 2004. Samples collected in 2011 and 2012 demonstrated that there were multiple length cohorts in the population including juveniles (12–130 mm total length TL) and large (>300 mm TL) adult fish. Gonadal assessment of adults demonstrated the presence of reproduction capable specimens. The concurrent occurrence of mature adults and juvenile fish demonstrated establishment. Locality records indicate that P. disjunctivus has already spread between two rivers through an inter basin water transfer. Using a unified framework for invasions this invasion was categorized as a self-sustaining population in the wild with individuals surviving and reproducing a significant distance from their original point of introduction. Containment is suggested as potential management strategy.
- Full Text:
- Date Issued: 2013
Contrasting habitat associations of imperilled endemic stream fishes from a global biodiversity hot spot
- Authors: Chakona, Albert , Swartz, Ernst R
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:7148 , http://hdl.handle.net/10962/d1011850 , http://www.biomedcentral.com/1472-6785/12/19
- Description: Knowledge of the factors that drive species distributions provides a fundamental baseline for several areas of research including biogeography, phylogeography and biodiversity conservation. Data from 148 minimally disturbed sites across a large drainage system in the Cape Floristic Region of South Africa were used to test the hypothesis that stream fishes have similar responses to environmental determinants of species distribution. Two complementary statistical approaches, boosted regression trees and hierarchical partitioning, were used to model the responses of four fish species to 11 environmental predictors, and to quantify the independent explanatory power of each predictor.
- Full Text:
- Date Issued: 2012
Invasion of a headwater stream by non-native fishes in the Swartkops River system, South Africa
- Authors: Ellender, Bruce R , Weyl, Olaf L F , Swartz, Ernst R
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446866 , vital:74566 , https://doi.org/10.1080/15627020.2011.11407477
- Description: In South Africa, fishes in headwater streams are increasingly being threatened by non-native fish invasions. These invasions originate primarily from source populations in mainstream rivers and impoundments. In the Blindekloof stream, a Swartkops River headwater tributary, the non-native Micropterus salmoides was eradicated from the stream by conservation authorities in 1989. As a result of this eradication subsequent occurrences of non-native fishes are most likely a result of upstream invasions from the mainstream Swartkops River. The Blindekloof stream therefore provided a unique opportunity to investigate whether M. salmoides would reinvade after its removal in 1989 and if the more recently introduced Clarias gariepinus and Tilapia sparrmanii would invade the Blindekloof stream. During snorkel and electrofishing surveys four non-native species were recorded (M. salmoides, M. dolomieu, T. sparrmanii, C. gariepinus ).
- Full Text:
- Date Issued: 2011