The main aim was to compare the population status of Cottus gobio before and after eradication activities on Atlantic brown trout, carried out in two watercourses of the Marche region, as specified by the concrete conservation actions of the LIFE+ TROUT Project (LIFE12 NAT/IT/0000940). In total 1125 specimens of the European bullhead were collected and five age classes (0+ to 4+) were identified. In both populations, the average density values resulted significantly higher after the eradication activities. The equation of the total length-weight relationship for the total sample was W=0.0326TL2.5727. The parameters of the theoretical growth curves carried out separately for the two populations showed that, after the eradication activities, the populations were distinguished by greater performance, evaluated using the F’ parameter, and larger sizes in all age classes in comparison to the pre-eradication period. The results of the condition factor evaluation showed no differences in the comparison between the two periods, suggesting that the effects of the trout eradication acted through decreased predation and not through interspecific competition mechanisms. The information obtained demonstrate the positive effects of management actions as eradication of alien species, particularly effective for biodiversity conservation in freshwater ecosystems.
Stato delle popolazioni di Cottus gobio Linnaeus, 1758 in due corsi d’acqua dell’Italia centrale dopo l’eradicazione della trota atlantica Salmo trutta Linnaeus, 1758
Lorenzoni M.;Carosi A.;La Porta G.;
2017
Abstract
The main aim was to compare the population status of Cottus gobio before and after eradication activities on Atlantic brown trout, carried out in two watercourses of the Marche region, as specified by the concrete conservation actions of the LIFE+ TROUT Project (LIFE12 NAT/IT/0000940). In total 1125 specimens of the European bullhead were collected and five age classes (0+ to 4+) were identified. In both populations, the average density values resulted significantly higher after the eradication activities. The equation of the total length-weight relationship for the total sample was W=0.0326TL2.5727. The parameters of the theoretical growth curves carried out separately for the two populations showed that, after the eradication activities, the populations were distinguished by greater performance, evaluated using the F’ parameter, and larger sizes in all age classes in comparison to the pre-eradication period. The results of the condition factor evaluation showed no differences in the comparison between the two periods, suggesting that the effects of the trout eradication acted through decreased predation and not through interspecific competition mechanisms. The information obtained demonstrate the positive effects of management actions as eradication of alien species, particularly effective for biodiversity conservation in freshwater ecosystems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
