Genetic characterization of a putative indigenous brown trout (Salmo trutta fario) population in a secondary stream of the Nera River Basin (Central Italy) assessed by means of three molecular markers

Abstract

Genetic diversity was analysed in a putative autochthonous brown trout (Salmo trutta fario L.) population (Monterivoso Stream, Tyrrhenian Apennine Slope) by means of seven microsatellite loci and PCR‐RFLP of two mitochondrial (ND1 and ND5/6) and one nuclear (LDH‐C1*) locus. Monterivoso data were compared to those obtained analysing populations of the same basin (Nera River) and of the Po basin; Irish populations were used as a source of Atlantic strain brown trout. Haplotypes distributions, heterozygosity, F‐statistic and UPGMA analyses indicated a genetic diversification between these populations, suggesting a widespread alteration of the genetic structure due to repeated stocking with allochthonous material, mainly of Atlantic origin, that has partially polluted the Monterivoso population. This population appeared to be constituted of Mediterranean strain samples and might represent a residue of an indigenous pool: it shows high specificity characteristics and it is genetically separate from the others observed and from populations of the Adriatic slope of the Apennines. This population should be employed in managing and breeding programmes finalised to an eco‐sustainable restocking of brown trout in the Nera River Basin, with periodic monitoring by genetic analyses.