Norwegian Marble Trout (Salmo trutta): The Unique Marbled Trout of the Otra River
A journey into the world of one of the most beautiful fish found in Southern Norway. Not only is it aesthetically breathtaking but the environment where it lives equally so.
The Norwegian marble trout is a rare marbled morph of brown trout (Salmo trutta) found primarily in the Otra River system. Its unique genetics and striking patterning make it one of the most fascinating trout forms in Europe and a key conservation unit.
- Scientific name: Salmo trutta
- Unique morph with marbled pigmentation
- Origin: Otra River, Southern Norway
- Conservation status: Evolutionarily Significant Unit (ESU)
- Habitat: Lakes and rivers in the Otra catchment
Our first date
Some near 20 years ago, long before I had thoughts of being a professional fishing guide, I found myself fishing a beautiful part of the upper Otra river. Just North of Evje in Southern Norway below the dam at Syrtveit, Evje, the outflow of the dam is split into two main arteries by some wonderful islands which are intertwined by smaller river arterioles, but it's the two main arteries which is where two internationally unique salmonoids reside.
In this blog post I would like to take you on a journey into the world of one of the most beautiful fish I have had the pleasure of catching. Not only is it aesthetically breathtaking but the environment where it lives equally so and then add the fishing journey to bag such a specimen, well no words can quantify it. It must be experienced!
Origin and Post-Ice Age Evolution
So, let's start at the beginning. Some roughly 11700 years ago the last Ice Age casting its icy blanket over Norway, came to an end. The ice's edge gradually receded ever further North and salmonoids from the Atlantic lineage of trout (AT) from Europe followed, which is now found throughout Northern Europe. As the sea levels dropped, lakes and rivers were formed in what we now know as Norway, and in these pockets of water trapped the otherwise free moving salmonoids. Where my story continues is in the Otra river, one of the largest rivers in Agder and in Southern Norway itself.
The Otra is born from the mighty Setesdal mountains in the West and flows to the Southern tip, meeting the sea in what is now Norway's 6th largest city, Kristiansand. The Otra has a large catchment area which has many rivers, streams and hundreds of lakes feeding into it. At Syrtveit, where the dam is, the river has a variety of trout but these remarkably stand out from the rest with their unique marbled pattern and a range of beautiful colours.
Genetics and Conservation Status (ESU Explained)
These strikingly beautiful creatures can look very much like the marble trout (Salmo marmoratus) of the Balkans and Northern Italy but genetically they are a brown trout (Salmo trutta). Using microsatellites, mtDNA haplotypes and SNP markers, their genetics largely match those of their Scandinavian cousins but are what scientists call genetical morphisms which show convergent “marbled” phenotype due to pigmentation genetics. With this bears a label of ‘unique conservation unit’.
How to Fish for Norwegian Marble Trout
Our ‘marble’ trout more than often resides with their spotty brothers and sisters, and feed in exactly the manner.
Fly fishing – 8-9ft #4-5 rod with matching reel and line. Flies like daddy-long-legs, superpupan, klinkhammer, Gary Fontaine’s sparkle pupae have all worked well.
Lure fishing – A 7-9ft Ultralight or Light rod with 1000-2500 reel and matching line. My absolute favourite lure is the Sølvkroken Spesial orange blade with black body spinner, smaller the better.
Seasons tend to be from late April/May onwards into October though this season shortens the further North you fish and the higher you fish. Lakes high in the hills can have very short seasons from late May to early September.
Conclusion
So hopefully you’ve gotten enough information in the blog post to ‘whet your appetite’ and give it a go yourself. The hunt for these fish takes you to some naturally beautiful places and don’t be surprised if you have an osprey or two soaring overheard whilst you cast out your line.
Tightlines, Ryan.