Applicazione dell'Indice Ittico (I.I.) in Piemonte e sperimentazione del nuovo Indice di Stato Ecologico delle Comunità Ittiche (ISECI)

The results of a comparison between two widely used Ichthyic indexes, the Ichthyic Index (I.I.) and the new ISECI index, which follows EC 2000/60, is here reported. The comparison was performed over two sampling campaigns done in Piedmont in 2004 and 2009, the latter involving 429 sampling locations. Moreover the data on SECA, which summarizes the results of several biotic indexes, were also compared for 182 locations, to verify whether the data from Ichthyic indexes are coherent with those on biotic indexes base on other markers (macrobenthos, chemical composition of the water, diatoms). Both I.I. and ISECI give results coherent with those of SECA, although it is highlighted that often they give a complementary rather than confirmative information. It was also found that in general the II gives lower values (better quality) than ISECI. The critical effect of the inclusion of allochthonous species as markers for the Ichthyic indexes is discussed. Further investigation to other regions, to define zoogeographic areas and reference fish communities is needed