Ontogenetic Diet Shift of Invasive Gibel Carp (Carassius gibelio, Bloch 1782) in Karamenderes River (Turkey)

The ontogenetic diet shift of invasive Carassius gibelio (Bloch, 1782) was investigated in Karamenderes River, Turkey. The fieldwork was performed during summer 2012, autumn 2012 and spring 2013. The fishes were caught by electrofishing and using gill nets. Nine fork length groups were used in order to assess the ontogenetic diet shift. The gut contents were assessed by the index of relative importance that was calculated from the frequency of occurrence, numerical abundance, and volumetric analyses. The most abundant length groups of C. gibelio were 18-20 cm, 6-8 cm, and 27-29 cm length groups during summer 2012, autumn 2012 and spring 2013, respectively. The feeding intensity was the lowest in the length groups of 15-17 cm during summer 2012, in 3-5 cm length group in autumn 2012 and in 24-26 cm length group in spring. Seasonal variations were observed in the ontogenetic diet shift of C. gibelio. Large specimens consumed more animal materials during summer and more algae in autumn. There was not any significant niche overlap recorded between small and large specimens except summer. Any niche overlap between small and large specimens might be advantageous for the establishment success of invasive Gibel carp in Karamenderes River

An invasive species, Carassius gibelio, alters the native fish community through trophic niche competition

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.peerReviewe

Feeding Ecology of the Topmouth Gudgeon Pseudorasbora parva (Temminck and Schlegel, 1846) in the Gelingullu Reservoir, Turkey

Ozdilek, Sukran Yalcin/0000-0001-8264-7606;WOS: 000319466300011Pseudorasbora parva (Temminck and Schlegel, 1846) is widely distributed in rivers and lakes of Turkey owing to accidental introductions. Turkey is rich in biodiversity of freshwater fish and has a high level of endemicity of native ichthyofauna, which is vulnerable to such introductions. The Gelingullu Reservoir located on the Kizilirmak drainage in Central Anatolia has rich ichthyofauna with native and introduced fish species, including endemic species. The contents of the foregut of P. parva samples collected between Summer 2003 and Summer 2005 were examined. Seasonal and ontogenetic changes in feeding intensity were determined. P. parva mainly feeds on zooplankton such as Cladocera, Copepoda, and Rotifera. Members of the Bacillariophyta and Cyanobacteria were identified in high proportions in the foregut contents of P. parva particularly during summer. The feeding traits of this invasive fish may have an influence on the establishment of a successful population in Gelingullu reservoir

Feeding Ecology of the Topmouth Gudgeon Pseudorasbora parva (Temminck and Schlegel, 1846) in the Gelingullu Reservoir, Turkey

Ozdilek, Sukran Yalcin/0000-0001-8264-7606;WOS: 000319466300011Pseudorasbora parva (Temminck and Schlegel, 1846) is widely distributed in rivers and lakes of Turkey owing to accidental introductions. Turkey is rich in biodiversity of freshwater fish and has a high level of endemicity of native ichthyofauna, which is vulnerable to such introductions. The Gelingullu Reservoir located on the Kizilirmak drainage in Central Anatolia has rich ichthyofauna with native and introduced fish species, including endemic species. The contents of the foregut of P. parva samples collected between Summer 2003 and Summer 2005 were examined. Seasonal and ontogenetic changes in feeding intensity were determined. P. parva mainly feeds on zooplankton such as Cladocera, Copepoda, and Rotifera. Members of the Bacillariophyta and Cyanobacteria were identified in high proportions in the foregut contents of P. parva particularly during summer. The feeding traits of this invasive fish may have an influence on the establishment of a successful population in Gelingullu reservoir

Türkiyede Gelingüllü Barajında yaşayan pseudorasbora parva (Temminck and Schlegel, 1846) bireylerinin beslenme ekolojisi

Pseudorasbora parva (Temminck and Schlegel, 1846) Türkiyedeki göl ve akarsulara istenmeden karışarak geniş bir dağılım gösterir. Türkiye tatlı su balık çeşitliliği bakımından doğal ihtiyofauna elemanları arasında bu şekildeki istilacıların hassaslaştıracağı çok sayıda endemik tür içerir. Gelingüllü Barajı Orta Anadoluda Kızılırmak üzerinde yer alır ve endemik türler de dahil olmak üzere doğal ve istilacı türler ile zengin bir ihtiyofaunaya sahiptir. P. parva örneklerinin ön bağırsak içerikleri 2003-2005 arasında toplanan örneklerde incelendi. Beslenme şiddetindeki mevsimsel ve ontogenetik değişiklikler belirlendi. P. parva bireyleri başlıca Cladocera, Copepoda ve Rotifera gibi zooplanktonlarla beslenmektedirler. Yaz boyunca P. parva bireylerinin ön bağırsaklarında yüksek oranda Bacillariophyta ve Cyanobacteria üyelerine rastlandı. Bu istilacı balık türünün Gelingüllü Barajında başarılı bir populasyon kurmasında beslenme özellikleri etkili olabilir.Pseudorasbora parva (Temminck and Schlegel, 1846) is widely distributed in rivers and lakes of Turkey owing to accidental introductions. Turkey is rich in biodiversity of freshwater fish and has a high level of endemicity of native ichthyofauna, which is vulnerable to such introductions. The Gelingüllü Reservoir located on the Kızılırmak drainage in Central Anatolia has rich ichthyofauna with native and introduced fish species, including endemic species. The contents of the foregut of P. parva samples collected between Summer 2003 and Summer 2005 were examined. Seasonal and ontogenetic changes in feeding intensity were determined. P. parva mainly feeds on zooplankton such as Cladocera, Copepoda, and Rotifera. Members of the Bacillariophyta and Cyanobacteria were identified in high proportions in the foregut contents of P. parva particularly during summer. The feeding traits of this invasive fish may have an influence on the establishment of a successful population in Gelingüllü reservoir