2013. február 14., csütörtök

Ferincz et al. (2012) Acta Zoologica Academiae Scientiarum Hungaricae

This analysis of long-term (1992–2011) changes in the fish assemblage of the partially operating shallow, hypertrophic reservoir (Ingói-marsh, Lake Fenéki) was carried out on the occasion of the planned completion of the impoundment. Samplings were performed in standard localities with electrofishing. Three phases could be distinguished in fish fauna development. The first phase is characterized by two allochtonous marsh-species: the Mud-minnow (Umbra krameri) and the Crucian carp (Carassius carassius), and was fast replaced by the second invasion phase, characterized by the invasion of non-native gibel carp (Carassius gibelio),and the third phase by the dominance of roach (Rutilus rutilus) and bleak (Alburnus alburnus). The cumulative relative abundance of non-indigenous species reached a peak in the third year of the impoundment (1995; 56.4%), and remained high (>>50%) until 2001. The number of species, Shannon-Weaver diversity, and relative abundance of piscivorous species correlated positively with the age of reservoir. The shift of the fish fauna between the two phases was dynamic and dramatic, since the all previously dominant species disappeared within 4 years. The impact of invasive gibel carp is considered as high, because it has completely replaced its native relative (C. carassius), but in the other hand it only was able to delay the natural successive process, not completely transform it.

gibel carp, diversity, assemblage structure, shallow reservoir

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