- Title
- Birds as major predators of fishes in the East Kleinemonde Estuary
- Creator
- Cowley, Paul D, Whitfield, Alan K, Terörde, Anja I
- Subject
- To be catalogued
- Date
- 2017
- Type
- text
- Type
- article
- Identifier
- http://hdl.handle.net/10962/443271
- Identifier
- vital:74104
- Identifier
- https://hdl.handle.net/10520/EJC-c2893c53c
- Description
- This study provides a quantitative account of fish predation by piscivorous birds in the temporarily open/closed East Kleinemonde Estuary and represents the first global attempt to simultaneously relate such consumption to production by a fish community in the same estuary. Cormorants and herons were the dominant predators and seasonal variations in the avifaunal community composition were noted. Based on comprehensive counts over three years, the piscivorous bird population was estimated to have consumed a maximum of 4 414 kg of fish in 1994, 2 400 kg in 1995/96 and 2 960 kg in 2004/05. In 1995/96 fish production in the East Kleinemonde Estuary (55.89 g m−2 a−1) was estimated at 9 780 kg and maximum bird predation amounted to 25% of annual fish production within the system over the same period, assuming that all birds counted on the estuary foraged there and that the diet of these birds comprised only fish. The above 1995/96 figures, together with an estimate of fish predation by the dominant piscivorous fish Lichia amia of 696 kg suggests that birds are probably the single most important natural predator of fishes within this estuary. An unusual mass invasion by marine Cape Cormorants Phalacrocorax capensis during July 1994 was responsible for large-scale predation of fish (2 155 kg) and resulted in the population of estuary-associated marine fishes declining from approximately 63 300 to about 18 600 individuals during the 1994 closed phase. Given that little or no marine fish recruitment was possible while the estuary mouth was closed, piscivorous birds are likely to have a higher predatory impact on populations of juvenile marine fishes in small temporarily closed estuaries than in larger permanently open systems.
- Format
- 8 pages, pdf
- Language
- English
- Relation
- African Zoology, Cowley, P.D., Whitfield, A.K. and Terörde, A.I., 2017. Birds as major predators of fishes in the East Kleinemonde Estuary. African Zoology, 52(3), pp.147-154, African Zoology volume 52 number 3 147 154 2017 2224-073X
- Rights
- Publisher
- Rights
- Use of this resource is governed by the terms and conditions of the Sabinet Terms and Conditions Statement (https://www.sabinet.co.za/terms-conditions)
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Collections
Cowley, Paul Denfer (Prof)
RU South African Institute for Aquatic Biodiversity (SAIAB)
SDG 15. Life On Land
RU Department of Zoology and Entomology
SDG 14. Life Below Water
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | Birds as major predators of fishes in the East Kleinemonde Estuary.pdf | 713 KB | Adobe Acrobat PDF | View Details |