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Comparisons between the characteristics of ichthyofaunas in nearshore waters of five estuaries with varying degrees of connectivity with the ocean
Citation
Hoeksema, SD and Chuwen, BM and Potter, IC, Comparisons between the characteristics of ichthyofaunas in nearshore waters of five estuaries with varying degrees of connectivity with the ocean, Estuarine, Coastal and Shelf Science, 85, (1) pp. 22-35. ISSN 0272-7714 (2009) [Refereed Article]
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The definitive version is available at http://www.sciencedirect.com
DOI: doi:10.1016/j.ecss.2009.04.025
Abstract
The characteristics of the fish faunas in nearshore, shallow (<1.2 m) waters of the basins of estuaries
along the same coastline, but which were open to the ocean for varying periods, have been determined
and compared. The fish faunas of the permanently-open Oyster Harbour, the seasonally-open Broke,
Irwin and Wilson inlets and the normally-closed Wellstead Estuary on the south coast of Western
Australia were sampled by seine net seasonally for 2 years. Irrespective of the frequency and duration
that the estuary mouth was open, the ichthyofauna of each estuary was numerically dominated by three
atherinid species and three gobiid species (92.999.7%), each of which completes its life cycle within
these estuaries. The ichthyofaunal compositions of each estuary differed significantly, however, from that
of each other estuary. These differences were largely attributable to the relative abundances of the above
six species varying between estuaries, which, in turn, reflected differences in such factors as estuary
mouth status, macrophyte cover and salinity. For example, Favonigobius lateralis and Leptatherina presbyteroides,
which are also represented by marine populations, were most abundant in the permanentlyopen
estuary (Oyster Harbour), which, in terms of substrate and salinity, most closely resembled the
nearshore marine environment. In contrast, Leptatherina wallacei made its greatest contribution in the
only estuary to exhibit a protracted period of greatly reduced salinities, which is consistent with its
distribution in permanently-open estuaries on the lower west coast of Australia, while Atherinosoma
elongata and Pseudogobius olorumwere particularly numerous in estuaries containing dense stands of the
seagrass Ruppia megacarpa. Marine species made the greatest contribution to species richness in the
permanently-open estuary and least in the normally-closed estuary. Species richness was greatest in
summer and least in winter in each estuary, but differed markedly between years only in Wilson Inlet.
Density of fishes was greatest in the most eutrophic estuary (Wellstead Estuary) and least in the most
oligotrophic estuary (Broke Inlet) and only underwent marked seasonal variations in Wilson Inlet and
Wellstead Estuary, in which densities fell to their minima in winter. Ichthyofaunal composition varied
between years in the Broke and Wilson inlets and Wellstead Estuary, in which there was little or no
connection with the ocean in one of those years. Species composition underwent progressive seasonal
changes throughout the year in Wellstead Estuary, due to the abundance of certain species peaking at
different times of the year.
Item Details
Item Type: | Refereed Article |
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Keywords: | microtidal estuaries estuary mouth ichthyofaunal composition, species richness and density temporal variability life-cycle guilds Western Australia, south coast 116.36119.42 E, 34.4135.04 S |
Research Division: | Environmental Sciences |
Research Group: | Climate change impacts and adaptation |
Research Field: | Ecological impacts of climate change and ecological adaptation |
Objective Division: | Environmental Management |
Objective Group: | Management of Antarctic and Southern Ocean environments |
Objective Field: | Biodiversity in Antarctic and Southern Ocean environments |
UTAS Author: | Chuwen, BM (Dr Ben Chuwen) |
ID Code: | 71837 |
Year Published: | 2009 |
Web of Science® Times Cited: | 19 |
Deposited By: | Sustainable Marine Research Collaboration |
Deposited On: | 2011-08-10 |
Last Modified: | 2011-10-27 |
Downloads: | 0 |
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