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Abstract

Changes in fish fauna, fish conditions and some physico-chemical features of water of Lake Ula which was established for irrigation purposes and subjected to introduction of non-native fishes were investigated. Six different fish species were found, five of them belong to Cyprinidae family; common carp Cyprinus carpio L., 1758, gibel carp Carrassius gibelio (Bloch, 1782), goldfish Carassius auratus (L., 1758), chub Squalius cephalus (L., 1758) and gizani Ladigesocypris ghigii (Gianferrari, 1927). The other species found was eastern mosquitofish Gambusia holbrooki Girard, 1859 from Poeciliidae family. Fulton's body condition values varied between 0.99 (chub) and 1.48 (gibel carp). Two Carassius species (non-native species) had significantly the higher condition values than those of other species (P<0.001). Comparison of condition data of chub and common carp from present study and published work in 1999 revealed no significant differences (t-test, P>0.05). Some physico-chemical features of water were compared and no big differences were detected between 1998 and 2009.

The ichthyofaunal diversity of freshwater ecosystems in Gökçeada Island (NW Turkey) under the pressure of nonnative species

“…Similar to the P. parva, C. gibelio was found only in Gökçeada Reservoir and its input water Tepeköy Stream. Such multiple introductions of gibel carp seem to be continuing through popular common carp introductions especially in newly created reservoirs throughout the country (Özuluğ et al, 2004;Önsoy et al, 2011;Tarkan et al, 2012). Natural spread through connected river systems (such as Meriç River) might have also been responsible for secondary non-native dispersion of this species within Turkish freshwater bodies.…”

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“…Andrews, 1990;Wheeler, 1991, North, 2000Marchetti et al, 2004;Ruesink, 2005;Önsoy et al, 2011). These artificial water bodies, which are generally created for water supply storage (i.e.…”

“…Treer et al, 1995;2003), it can also cause the accidental introduction of non-native fish species. Notable cases are those of goldfish Carassius auratus, gibel carp Carassius gibelio, eastern mosquitofish Gambusia holbrooki, pumpkinseed Lepomis gibbosus and topmouth gudgeon Pseudorasbora parva, all of which have been associated with the intentional stocking of common carp Cyprinus carpio (Özuluğ et al, 2005;Balık and Ustaoğlu, 2006;Önsoy et al, 2011). The latter is a widely-distributed Eurasian cyprinid, which is highly invasive and noxious in several areas of introduction (review in Vilizzi et al, 2015) but also threatened in parts of its native area of distribution (Balon, 1995).…”