Inter-seasonal persistence and size-structuring of two minnow species within headwater streams in the Eastern Cape, South Africa

Kadye, Wilbert T; Booth, Anthony J

Title: Inter-seasonal persistence and size-structuring of two minnow species within headwater streams in the Eastern Cape, South Africa
Creator: Kadye, Wilbert T
Creator: Booth, Anthony J
Date Issued: 2012
Date: 2012
Type: text
Type: article
Identifier: http://hdl.handle.net/10962/124866
Identifier: vital:35705
Identifier: https://doi.10.1111/j.1439-0426.2012.02027.x
Description: This study examined temporal variation in population dynamics and size structuring of two cyprinid minnows, Pseudobarbus afer and Barbus anoplus, in relation to their proximate physical habitats. Population estimates were determined using three-pass depletion sampling during both summer and winter. The habitats were characterised by seasonal variation in all physico-chemical conditions and spatial variation in substrata compositions. Whereas significant differences in population size were noted between seasons for B. anoplus, no differences were found between seasons for density and capture probability for either species. An increase in boulders was associated with increase in population size and density for P. afer; for B. anoplus, increased percentages of bedrock and bank vegetation were associated with an increase in population size and probability of capture, respectively. According to Canonical Correspondence Analysis, size structuring in P. afer was explained predominantly by seasonality, with smaller length classes associated with the seasonal variable of summer, while larger length classes were associated with pH that was higher in winter. By comparison, for B. anoplus, the habitat variables – bank vegetation and bedrock – accounted for much of the explained variance for size structuring. Recruitment appeared to be the major driver of size structuring for the two species; refugia, especially boulders and bank vegetation, also appeared to be important. Overall, the two species were adapted to the headwater streams that were generally variable in environmental conditions. Potential invasions by non-native invasive fishes that occur within the mainstream habitats threaten these two species. Efforts should continue to protect these minnows from such invasions by constructing barriers to upstream migration of non-native fishes into these headwater habitats.
Format: 9 pages
Format: pdf
Language: English
Relation: Journal of Applied Ichthyology
Relation: Kadye, W.T. and Booth, A.J., 2012. Inter-seasonal persistence and size-structuring of two minnow species within headwater streams in the E astern C ape, S outh A frica. Journal of Applied Ichthyology, 28(5), pp.791-799
Relation: Journal of Applied Ichthyology volume 28 number 5 791 799 2012 0175-8659
Rights: Journal of Applied Ichthyology
Rights: Use of this resource is governed by the terms and conditions of the Wiley Online Library Terms of Use statement (https://onlinelibrary.wiley.com/terms-and-conditions)

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Kadye, Wilbert T (Dr)

Booth, Anthony John (Prof)

RU Department of Ichthyology and Fisheries Science

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