FISH STOCKINGS TO NEWLY FORMED MAN-MADE RESERVOIRS IN TURKEY: ECOLOGICAL DISASTERS OR SOCIOECONOMIC BENEFIT?


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Aydın H. , Gaygusuz Ö., Tarkan A. S. , Dorak Z.

The 5th Iberian Congress of Ichthyology., Lisbon, Portekiz, 24 - 27 Haziran 2014, cilt.1, no.1, ss.1

  • Cilt numarası: 1
  • Basıldığı Şehir: Lisbon
  • Basıldığı Ülke: Portekiz
  • Sayfa Sayıları: ss.1

Özet

The stocking of freshwater fishes is a common worldwide practice mainly for aquaculture and angling-related purposes. In Turkey, this is mainly carried out in newly established water reservoirs to enhance fish production and sportive fishing however several non-native fish species have been introduced mostly through unintentional or unauthorized stocking associated with intentional stocking of common carp, Cyprinus carpio. The aim of the present study is to understand whether these fish stockings to newly established reservoirs provide an increase in production of native and desirable fish fauna of these environments or it triggers non-native fishes’ distribution and further spread by decreasing efficiency of the stockings due to  increase unwanted and unexploited non-native fish species. For this purpose, a representative region in northwestern of Anatolia, Turkey (Kocaeli Peninsula) was studied between 2009 and 2011. A total of 20 fish species including 6 non-native species was collected from 13 reservoirs. Non-native gibel carp, Carassius gibelio was the most abundant and frequently encountered species followed by endemic species Pursak chub, Squalius pursakensis. Non-native fish species richness has been found to distribute disproportionally among the reservoirs but their relative abundances increased while native species abundance decreased over three-year study period. Non-native fish species showed a poor environmental relevancy compared to native species but they tend to have wider environmental tolerance ranges and higher optimum environmental values than native species. Theme: Ecological and fishery conditions for additive effects of stocking