Entries in Brown trout stocking (2)

Marble Trout

marble%20trout.jpg

I wanted to give a plug to the Balkan Trout Restoration Group  for their efforts in conserving Marble Trout. I have never fished the River Soca, but have dreamt of it. Perhaps one of the most beautiful rivers in Europe? Clear waters with limestone bedrock giving rise to plentiful insect life. And the record for a Marble Trout was 40 lbs taken back in 1928.

But there are some big difficulties for conservation. The Balkans give rise to some of the most complicated evolutionary genetics involving trout yet studied. The three major catchments that drain into the Black, Aegean and Adriatic seas have each created separate strains of trout ( I hesitate to use the term species). But the picture seems more complicated than this. Siminovic (Jnl Fish Biology June 2007 vol 70) indicates more than 12 types of trout, postulating that Marble trout have a recent origin from the West Danubian stock. Snoj et al (same journal) have discovered a new type of trout on the River Neretva bearing characteristics between Marble and Softmouth trout (the so called Salmo Montegrinus). Torben et al (Biological Conservation May 2007 vol 136) warn that hybrids between Brown trout and Marble trout are fertile and become predominant due to greater fitness.

These findings indicate difficulties for Marble trout rehabilitation. Hybridisation may soon be the end of some species. But part of me thinks that it is a wonder that so many types of trout have managed to retain genetic stability in such a small area. Perhaps this gives us hope!

 

Brown Trout Genetics

Why might stocking with farm-reared brown trout have a negative influence on sea trout runs?

Why is interbreeding of farm-reared and wild brown trout a problem?

What is the evidence that farm-reared trout and farm-wild hybrids have reduced fitness compared to wild trout?

Here are Professor Andy Ferguson's answers.