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    An invasive species, Carassius gibelio, alters the native fish community through trophic niche competition
    (Springer Basel Ag, 2019) Yalçın Özdilek, Şükran; Partal, Nurbanu; Jones, Roger I.
    Carbon and nitrogen stable isotope analyses were used to determine isotopic niche width of the invasive fish species Carassius gibelio to help assess the niche overlap and potential impact of this species on the native fish fauna in the Karamenderes River, northwest Turkey. C. gibelio had the highest niche area of the coexisting species. The greatest overlap of isotopic niche was between C. gibelio and Mugil cephalus in the river mouth. The freshwater species displayed similar patterns when taking into consideration their relative abundance and isotopic overlap. While C. gibelio is likely to outcompete some species at some localities, the species was found co-occurring with others by maximum tolerable overlap degree and apparently utilised vacant niche space at some stations. Overall our results indicate that C. gibelio has extensive niche overlap with the native fish species making it a strong competitor, and because of its high abundance and high niche width this invasive species represents a serious threat to the native fish fauna, particularly in the river mouth.
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    Öğe
    The Diet Composition and Trophic Position of Introduced Prussian Carp Carassius gibelio (Bloch, 1782) and Native Fish Species in a Turkish River
    (Central Fisheries Research Inst, 2014) Yalçın Özdilek, Şükran; Jones, Roger I.
    Carbon and nitrogen stable isotope analyses were carried out to determine the diet composition and trophic position of the invasive species Carassius gibeho to help understand the potential impact of this species on the native fish fauna in the Karamenderes River, northwest Turkey. Filamentous algae were the most important diet component according to stable isotope mixing models. Filamentous algae and detritus formed also considerable part of the gut contents. The trophic position of C. gibeho was 2.43 +/- 0.5, 2.04 +/- 0.4 and 3.35 +/- 0.5 estimated by three different methods. The trophic niche width of this invasive species was larger than those of the native species. Our results indicate that the high dietary plasticity of C. gibelio and its lower trophic position than the other fish community members, can contribute to its success as an invasive species.