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The influence of selected environmental parameters on the distribution of the dominant demersal fishes in the Kariega Estuary channel, South Africa

The influence of selected environmental parameters on the distribution of the dominant demersal... The Kariega Estuary channel was sampled using an otter trawl and the demersal fish catch analysed using the PRIMER statistical package. A biological-environmental (BIOENV) analysis was undertaken using the catch per unit effort ichthyofaunal data from the spring/summer period of 1996/97 and concurrent water temperature, salinity and turbidity data. No strong correlations between the ichthyofauna and recorded physico-chemical parameters were documented, although temperature did show a weak correlation to demersal fish distributions. A second sampling programme undertaken in 2004 was specifically designed to test the influence of sedimentary characteristics on the distribution patterns of the dominant demersal species. Analyses showed that sediment size composition and organic content was strongly correlated (r = 0.70) to the distribution of the soles Solea bleekeri and Heteromycteris capensis, as well as the goby Glossogobius callidus. S. bleekeri and G. callidus showed a preference for the muddier middle and upper reaches of the Kariega Estuary channel, whereas H. capensis and Psammogobius knysnaensis were more abundant in the sandier lower reaches and mouth region of the estuary. The exact reasons for these preferences are unknown but are likely to be related to preferred prey availability, foraging success and predator avoidance in the different types of sediment. Other species caught in the otter trawl were not significantly correlated to sedimentary characteristics. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png African Zoology Taylor & Francis

The influence of selected environmental parameters on the distribution of the dominant demersal fishes in the Kariega Estuary channel, South Africa

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The influence of selected environmental parameters on the distribution of the dominant demersal fishes in the Kariega Estuary channel, South Africa

Abstract

The Kariega Estuary channel was sampled using an otter trawl and the demersal fish catch analysed using the PRIMER statistical package. A biological-environmental (BIOENV) analysis was undertaken using the catch per unit effort ichthyofaunal data from the spring/summer period of 1996/97 and concurrent water temperature, salinity and turbidity data. No strong correlations between the ichthyofauna and recorded physico-chemical parameters were documented, although temperature did show a weak...
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Publisher
Taylor & Francis
Copyright
© Zoological Society of Southern Africa
ISSN
2224-073X
eISSN
1562-7020
DOI
10.1080/15627020.2006.11407339
Publisher site
See Article on Publisher Site

Abstract

The Kariega Estuary channel was sampled using an otter trawl and the demersal fish catch analysed using the PRIMER statistical package. A biological-environmental (BIOENV) analysis was undertaken using the catch per unit effort ichthyofaunal data from the spring/summer period of 1996/97 and concurrent water temperature, salinity and turbidity data. No strong correlations between the ichthyofauna and recorded physico-chemical parameters were documented, although temperature did show a weak correlation to demersal fish distributions. A second sampling programme undertaken in 2004 was specifically designed to test the influence of sedimentary characteristics on the distribution patterns of the dominant demersal species. Analyses showed that sediment size composition and organic content was strongly correlated (r = 0.70) to the distribution of the soles Solea bleekeri and Heteromycteris capensis, as well as the goby Glossogobius callidus. S. bleekeri and G. callidus showed a preference for the muddier middle and upper reaches of the Kariega Estuary channel, whereas H. capensis and Psammogobius knysnaensis were more abundant in the sandier lower reaches and mouth region of the estuary. The exact reasons for these preferences are unknown but are likely to be related to preferred prey availability, foraging success and predator avoidance in the different types of sediment. Other species caught in the otter trawl were not significantly correlated to sedimentary characteristics.

Journal

African Zoology – Taylor & Francis

Published: Apr 1, 2006

Keywords: estuaries; demersal fishes; salinity; temperature; sediments

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