Search Results (3)

The Mediterranean trout (currently referred to as Salmo ghigii for Corsican and Italian-native populations) is listed as Endangered in the IUCN Red List, due to fragmented distribution and declining populations across its whole range, and is included in Annex II of the European Habitat Directive. The widespread genome introgression from the invasive Atlantic trout (Salmo trutta), overexploitation, and habitat alterations represent major threats to the persistence of native populations. The LIFE18NAT/IT/000931 STREAMS project aims to enhance conservation status of Mediterranean trout in 6 Italian pilot areas (Maiella, Sibillini Mountains, Casentino Forests and Pollino National Parks, Montemarcello-Magra-Vara Regional Park, and Sardinia with five sites of the Natura 2000 Network), and in 19 transferability areas covering almost the whole Italian species range. To achieve this, the following conservation strategies were implemented: (i) the identification of residual native populations; (ii) eradication of entirely Atlantic-exotic populations and removal of hybrids in admixed populations; (iii) restocking/reintroduction of native populations; (iv) monitoring/improving the Mediterranean trout habitats quality; (v) production of the “Guidelines for the conservation and management of native Mediterranean trout and its habitat”; and (vi) the prevention of illegal stocking. Here, we present the project rationale, major outcomes on demographic and genetic characterization of wild populations, and summary results from conservation actions. Full article

During the last 150 years, the trout-culture industry focused on enhancing trout populations by stocking, in response to the growing anglers’ demand and the habitat degradation associated to the rapid urbanization and hydropower development. The industrialized north of Italy, home to the Italian Alpine and subalpine trout populations, is the source of most of the revenues of the national trout-culture industry. Its rapid growth, and the massive introduction of non-native interfertile trouts eroded the genetic diversity of native lineages, leading to harsh confrontations between scientists, institutions, and sportfishing associations. We review here the state of the art of the taxonomy and distribution of the northern Italian native trouts, presenting both scientific results and historical documentation. We think the only native trouts in this region are Salmo marmoratus, widespread in this region, plus small and fragmented populations of S. ghigii, present only in the South-western Alps. We strongly recommend the interruption of stocking of domesticated interfertile non-native trouts in this area, and recommend the adoption of Evolutionary Significant Units for salmonid fishery management. We further propose future research directions for a sustainable approach to the conservation and ecosystem management of the fishery resources and inland waters of northern Italy. Full article

Brown trout is considered a complex of incipient species, including several phylogenetic lineages, whose natural distribution in the Mediterranean area has been altered, since the beginning of the 1900s, by massive introductions of domestic strains of Atlantic origin to support fisheries. Introduced trout naturalize in new suitable environments and extensively hybridize with native populations. Here, we characterized putatively neutral and adaptive genetic variability and population structure of Mediterranean brown trout from six river catchments in central peninsular Italy, as revealed by both mitochondrial (Control Region) and nuclear (microsatellites, LDH-C1, major histocompatibility complex) markers. We quantified the admixture of wild populations with hatchery strains and evaluated the effects of domestic trout introductions on shaping population genetics. Our analyses indicated: (1) a composite picture of genetic variability in the area, with the presence of all native Mediterranean trout mitochondrial lineages (“Adriatic”, “Mediterranean”, “marmoratus”), various frequencies of allochthonous genotypes and different rates of introgression among sampling sites; (2) asymmetric mito-nuclear introgression; (3) increasing nuclear marker diversity with increasing levels of admixture across populations; (4) strong population structure coupled with relatively low effective population size. Data allowed the identification of five management units and we propose specific actions to support ongoing and future conservation strategies within the examined area. Full article