The core of the hucho populations is in the Balkans

Ljubljana, March 19, 2015. As a contribution to the world water day this year (March, 22.) scientists and experts in the field of fisheries, together with non-governmental organizations presented a survey on the distribution of hucho (Hucho hucho) populations in the Balkans. In the framework of the international campaign "Save the Blue Heart of Europe", 18 scientists from seven countries for the first time carried out an extensive survey of the distribution of hucho populations in rivers between Slovenia and Montenegro. The results showed that the Balkan rivers represent the last hot spot of this species. Natural populations were found in 43 hucho rivers in total length of 1.842 kilometers, corresponding to 65% of all populations globally.

>Miroslav Žaberl, the president of the Fisheries Association of Slovenia, Neža Posnjak, Campaign Coordinator for Slovenia, Ulrich Eichelmann, RiverWatch, and Steve Weiss, Karl-Franzens University Graz, at the press-conference in Ljubljana. 

The major threat to these populations is a massive hydropower development plan. Practically all hucho rivers are targets of substantial hydropower exploitation. A total of 93 dam projects were identified directly in river reaches supporting hucho and a large number of additional projects are located in tributaries or headwater reaches upstream of hucho habitat that will invariably degrade environmental conditions downstream. The full study can be found at: http://balkanrivers.net/sites/default/files/Huchen_Study_2015.pdf 

>Uli is stocking hucho into the Sava River close to Ljubljana.

Two comprehensive papers on trout in Slovenia have been recently published

In Ribič (2015, 1-2), the gazette of National Union for fishing in Slovenia, Aleš, Klavdija, Nejc and Simona published a review of the work we have done on brown trout so far, with emphasis on more detailed presentation of the results referring to the last applied research project entitled Genetically-based analysis of endangered native brown trout (Salmo trutta) in Slovenia and identification of its genetically pure resources.

On the basis of molecular data that Gašper had produced for his PhD, we wrote an article entitled: Population genetic SNP analysis of marble and brown trout in a hybridization zone of the Adriatic watershed in Slovenia, which has been recently published in Biological Conservation (2015, 184, p. 239-259).

Some highlights:

• Most introgression has occurred from brown trout Atlantic lineage
• Hybrid swarms were found mostly in main rivers, but as well in some small unmanaged streams
• A high proportion of genetically non-introgressed (pure) marble trout was found in the upper Soča river
• Non-introgressed marble trout can still be found in the hybridization zone
• Discordance between mtDNA and nDNA due to asymmetric introgressive hybridization was observed

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