Differences in trophodynamics of commercially important fish between artificial waterways and natural coastal wetlands
نویسنده
چکیده
Extensive artificial waterways have replaced natural wetlands and created new estuarine habitats on the southernQueensland coast, Australia. Economically important fish species found in adjacent natural wetlands of mangrove, saltmarsh and seagrass also occur in the artificial waterways. Stable isotope analyses (dC, dN)were used to test whether the relative importance of basal sources of energy varied for foodwebs found in artificial (canals and tidal lakes) and natural waterways. None of the fish species differed in their isotope values between artificial waterways. In contrast, isotopic signatures of snub-nosed garfish (Arrhamphus sclerolepis; Hemiramphidae) varied greatly between natural and artificial waterways, having highly enriched dC values ( 10.5&) in natural wetlands, demonstrating reliance on seagrass ( 11.4&), and significantly less enriched values ( 19.0&) in artificial waterways, consistent with either local algal sources ( 19.8 to 20.4&) or amixture of seagrass andother less enriched autotrophs fromadjacent naturalwetlands. Isotopic signatures of sandwhiting (Sillago ciliata; Sillaginidae)were also significantlymore enriched innatural ( 18.2&) thanartificial ( 21.0&) habitats, but means were not far enough apart to distinguish between different sources of nutrition. dC values of yellowfin bream (Acanthopagrus australis; Sparidae) did not differ between artificial and natural habitats (about 20& in both). dN values of fish varied among habitats only for A. sclerolepis, which in artificial waterways had values enriched by 2& over those in natural waterways. This was consistent with a shift from seagrass (relatively depleted dN) as a source in natural habitat to algal sources (relatively enriched dN) in artificial habitats. This study provides some of the first evidence that at least some fish species rely on different autotrophs in artificial waterways than in adjacent natural wetlands. 2003 Elsevier Ltd. All rights reserved.
منابع مشابه
Trophic strategies of garfish, Arrhamphus sclerolepis, in natural coastal wetlands and artificial urban waterways
We used carbon stable isotope and stomach content analyses to test whether snub-nosed garfish, Arrhamphus sclerolepis (Hemiramphidae), in the extensive artificial urban waterways of southeast Queensland, Australia, rely on autotrophic sources different to those in natural wetlands. Carbon isotope values of A. sclerolepis were similar to those in previous investigations, with enriched values in ...
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