No. 25 (2007): Pisces Hungarici I. (Supplement Issue)
Articles

The fishfauna of the Crişul Repede river and its threatening major factors

Published April 11, 2007
Ilie C. Telcean
Faculty of Sciences, Department of Biology, University of Oradea, Romania
Diana Cupşa
Faculty of Sciences, Department of Biology, University of Oradea, Romania
S. D. Covaciu-Marcov
Faculty of Sciences, Department of Biology, University of Oradea, Romania
I. Sas
Faculty of Sciences, Department of Biology, University of Oradea, Romania
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APA

Telcean, I. C., Cupşa, D., Covaciu-Marcov, S. D. ., & Sas, I. (2007). The fishfauna of the Crişul Repede river and its threatening major factors. Acta Agraria Debreceniensis, (25), 13–18. https://doi.org/10.34101/actaagrar/25/3031

The Crişul Repede River is belonging at Cris (Körös) Rivers system which is a tributary on the left shore of Tisa River. In the last decades the fishfaunaofthenaturalwatershasundergoingadeclineinthespeciesnumber.Theothersuccessiveprocessisthefishspeciesreplacement due by the immigration of some exotically fishesandtheretirementofsomeofthenativespecies.
The Crişul Repede fishfaunahasregisteredadeclinecausedmainlybytheriverdamming,waterpollutionandeutrophisation.Ondespite of that negative factors the fishesfromtheupperriverwasmaintainlessaffectedunliketotheotherrivers.Thereaftertheeconomical transition and the industries reorganization process were redounded to diminishing the impact of these harmful factors. The former studies about the Cris fishfaunacitedanumberof48nativespeciesand12exoticones.Duringtheresearchtripscarriedoutsince10yearsago (beginning in 1995) was identifiedanumberof40fishspeciesandthepresenceoftheother8 speciesarestilluncertain.Thesturgeonspecies Acipenser ruthenus and the migratory fishAnguillaanguillahaveascarcepresenceandtheycannotbefoundinthelastdecade.A number of 5 exotically fishesarebehavedasremarkableintrudersinnaturalwaters:Pseudorasboraparva,Carassiusauratusgibelio,Ictalurus nebulosus, Ictalurus melas, and Lepomis gibbosus. Some of the exotically fishesalreadyrecordedintheHungarianstretchesofthe Crisuri (Körös) was not recorded in the Romanian section of the river (Mylopharyngodon piceus, Ictiobus bubalus, Ictalurus punctatus, Clarias gariepinus, Micropterus salmoides, Oreochromis niloticus, Perccottus glenii). The pervading of these species is expecting also in the Romanian section of the rivers.
The present major threatening factors concerning the fishfaunaarerepresentedbythehabitatchanges.Theriverdammingandtheriverside levees have a negative influenceonthefishfauna.Theformerphenomenonofwaterpollutionitseemsthatisreplacedbythehabitat changes. The dam lakes caused unregulated fluctuationsonthewaterlevelandtemperaturedownstreamofit.Theembankmentforpreventing the floodingwasperformedthroughshorteningtherivermeander.Thelostmeandersoftheriversarerepresentinganoptimalhabitat for fishspawning.

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