To test ecological niche theory, this study investigated the spatial patterns and the environmental niches of native and non-native fishes within the invaded Great Fish River system, South Africa. For the native fishes, there were contrasting environmental niche breadths that varied from being small to being large and overlapped for most species, except minnows that were restricted to headwater tributaries. In addition, there was high niche overlap in habitat association among fishes with similar distribution. It was therefore inferred that habitat filtering-driven spatial organisation was important in explaining native species distribution patterns. In comparison, most non-native fishes were found to have broad environmental niches and these fishes showed high tolerance to environmental conditions, which generally supported the niche opportunity hypothesis. The proliferation of multiple non-native fishes in the mainstem section suggest that they form a functional assemblage that is probably facilitated by the anthropogenic modification of flow regimes through inter-basin water transfer. Based on the distribution patterns observed in the study, it was inferred that there was a likelihood of negative interactions between native and non-native fishes. Such effects are likely to be exacerbated by altered flow regime that was likely to have negative implications for native ichthyofauna.
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http://dx.doi.org/10.1111/jfb.13988 | DOI Listing |
Vet Res Commun
January 2025
Department of Clinical Sciences and Translational Medicine, Faculty of Medicine, University of Rome "Tor Vergata", Via Montpellier 1, Rome, 001 33, Italy.
In our study, fancy southern platyfish Xiphophorus maculatus (Cyprinodontiformes, Poeciliidae) were examined due to breathing disorders and mortality. Fish came from Vietnam farm and were redistributed by international wholesaler. In fish, loss of appetite and gasping near the water surface was observed.
View Article and Find Full Text PDFPLoS One
January 2025
UMR CRBE (Center for Research on Biodiversity and Environment), CNRS5300, IRD, INP, UPS, Université Paul Sabatier, Toulouse, France.
The introduction of non-native fish species into new environments has raised global concerns due to potential ecological impacts on recipient ecosystems. A previous study focusing on the introduced fish species Arapaima gigas in Bolivian Amazon waters showed that its isotopic niche significantly overlapped with most co-occurring native fish species, suggesting potential competition. To evaluate this hypothesis, we extended here the investigation by comparing the trophic position and isotopic niche width of eleven abundant native fish species inhabiting both colonized and non-colonized floodplain lakes.
View Article and Find Full Text PDFSci Rep
December 2024
Global Ecology | Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia.
Assessing actual and potential impacts of non-native species is necessary for prioritising their management. Traditional assessments often occur at the species level, potentially overlooking differences among populations. The recently developed Dispersal-Origin-Status-Impact (DOSI) assessment scheme addresses this by treating biological invasions as population-level phenomena, incorporating the complexities affecting populations of non-native species.
View Article and Find Full Text PDFPLoS One
December 2024
College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America.
The capacity for a non-native species to become invasive largely hinges on existing dispersal capacity or adaptation of dispersal in new environments. Here we provide early evidence that invasive Northern Pike (Esox lucius), a Holarctic freshwater top predator, illegally introduced in the late 1950s into Southcentral Alaska, are now dispersing through estuarine corridors. This finding represents the first known documentation of estuary use and dispersal by Northern Pike in North America, exacerbating conservation concerns for already depressed populations of culturally and economically important species such as salmonids.
View Article and Find Full Text PDFPLoS One
December 2024
Hull international Fisheries Institute, University of Hull, Kingston upon Hull, United Kingdom.
Species presence/absence data in different water bodies in different regions of Saudi Arabia were collated from the literature and collected from field surveys to determine the geographical distribution of fish species in the country. Freshwater fish are mainly located in drainages in the south-west of the Kingdom of Saudi Arabia, both in the lowlands (western drainage systems) and highlands (eastern drainage systems) of the Sarawat Mountain Range. The eastern drainage systems were dominated by three endemic species, while the western drainage systems had a variety of endemic and non-native species.
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