The Italian Alpine and Subalpine trouts: Taxonomy, Evolution, and Conservation

Area of Science:

• Ichthyology
• Conservation Biology
• Fisheries Science

Background:

• Trout-culture industry in Northern Italy has historically relied on stocking to meet angler demand and offset habitat degradation.
• Industrialization and hydropower development have led to significant habitat loss for native trout populations.
• Introduction of non-native, interfertile trout species has severely eroded the genetic diversity of native Italian trout lineages.

Purpose of the Study:

• To review the current taxonomy and distribution of native trout in Northern Italy.
• To provide scientific and historical data on native trout populations.
• To recommend conservation strategies for native trout and sustainable fishery management.

Main Methods:

• Review of scientific literature and historical documentation on trout taxonomy and distribution.
• Analysis of the impact of stocking practices on native trout genetic diversity.
• Assessment of current fishery management strategies.

Main Results:

• Identified *Salmo marmoratus* as widespread and *S. ghigii* as having small, fragmented populations in the South-western Alps as the only native trout in the region.
• Documented the genetic erosion of native lineages due to the introduction of non-native trout.
• Highlighted conflicts between scientific findings, institutional practices, and sportfishing associations.

Conclusions:

• Strongly recommend ceasing the stocking of domesticated, non-native trout in Northern Italy.
• Advocate for the adoption of Evolutionary Significant Units for effective salmonid fishery management.
• Propose future research for sustainable conservation and ecosystem management of Italian inland waters and fishery resources.