New and most effective alternative for rigorous eradication

While being in Slovenia in December René Beaumont also met representatives of the renowned Ribiška družina Tolmin. This angling association stands for much more than just selling tickets. Since long sport fishing in the area has been recognized as an important recreational resource. In this respect the association and its members do their utmost to protect and improve the local aquatic ecosystems, the marble trout being ‘the main feature’ therein. Only some ten years ago this endemic species was on the brink of extinction due to hybridization with (non-native) brown trout, which have been intensively stocked into the Soča River for almost a hundred years. With crucial help of conservation genetics, marble trout populations have been restored and saved. These interventions prevented the population’s genotype from degrading into a non-descript gene swarm. What’s more, the continued existence of the species in all its purity has had a huge positive impact on the local economy since.

In the area a vast conservation program for safeguarding this flamboyant trout is at work. This program is led by Dr. Alain Crivelli (Tour du Valat, Arles, France) with the Tolmin Angling Association as a partner. Involved are many scientific institutions from Europe and USA, of which with the University of Ljubljana/Balkan Trout Restoration Group plays a very important role in. The conservation program led to lots of scientifically relevant results considering genetics, population dynamics, viability, nutrition and so on. Many of these results have already been implement in the further management of the marble trout.

The program brought a brand new approach for eliminating hybrids in the watersheds without harming or damaging the ecosystem as such. Within soon, substantial numbers of young, purebred marble trout farmed at the association’s hatcheries will be brought into action in order to literally push back the ‘genetic contamination’. They are expected to do so right from the very sources of the tributaries down to the tail waters.

The tide that seemed to be irreversible has been turned. The shortage of appropriate genetic material available once ‘forced’ the marble trout to hybridize with brown trout. Now the abundance of one hundred percent genuine material will contribute to increasing not only genetic purity but also genetic diversity.

Please note: this project is, in fact, beyond the Association’s budget. During the discussions with a.o. Dušan Jesenšek (RdT) and Aleš Snoj (BTRG) it was suggested to ask anglers, when purchasing their fishing permits for the 2014 season, to consider making a donation to help the Ribiška družina Tolmin out. Knowing that fishing permits are sold at very democratic prices CTCF strongly supports this idea!

Photo above: one hundred percent pure Soča marble trout (author: Arne Hodalič)