Surna 2015.

05.09.2015 09:50


An afterthought.


The salmon fishing is ended for this year. Gaula has fished 24 ton, Orkla 19 ton and Surna 2.4 ton. The shadow making is overwhelming, even the river owners are hesitant when to sell salmon fishing. We compare Surna with the rivers in Tröndelag: for example ‘Vitenskapelig Råd for Lakseforvaltning’ compare with gyro infected rivers like Driva and Rauma in Möre & Romsdal.

Statkraft claims it is good fishing in Surna and there is no reason to change the concession and conditions from 1962 for the Trollheim water power station. The economic numbers from Statkraft are devastating if the conditions are changed but Fiskeraksjonen shows 7 % decline of power production to maintain Surna as a salmon river. Unfortunately many politicians choose to believe Statkraft. Why shouldn’t they, is not a government cooperation speaking the truth? The power industry accuses the fish farming industry to be responsible for the salmon decline and the farming industry accuses back. Both are right sometimes but on different years and rivers. We shall sort out what is important for Surna.

In Figure 1 you can see the harvest from Surna the years 1989 to 2015 (The River Cooperation's catch statisics). We do not include Catch & Release because we can not see it influence the salmon catch statistics, the put back salmon might be killed by the next angler. The fishing limitations and the sea lice density also don’t give a footprint in the catch statistics, in contrast the sea trout that lives among the sea lice has almost disappeared. Salmon catch statistics of Surna is a school example when a river habitat declines, see Figure 1 and 2. The major responsibility for the decline of biological diversity and salmon in Surna is the maneuvering of Trollheim Water Power Plant.

The last strong salmon population of Surna goes to an end. It has five years from spawning to spawning, year 1995, 2000, 2005, 2010, etc. We had expected about 3 ton of harvest but it became 2.4 ton year 2015. A salmon that spends one year in the ocean is called a small salmon, two years in the ocean a medium salmon and three and more years a large salmon. At first the large salmon disappears when a salmon river declines, transforms to medium salmon a year ahead. In the end the medium salmon tries to survive by transforming to small salmon. Deep pools are filled due to reduced flooding and give less shelter and food. The salmon has to use more accumulated metabolism to grow to smolt size and gets less number of years to puberty, less number of years in the ocean to grow. Like a reverse puzzle the salmon populations disappear and become fragmented in the river, in the end only one real population remains.

In year 2014 there was about 150 more small salmon in Surna than the corresponding years of 2004, 2009, etc. If we convert these supernumerary small salmon of 2014 to medium salmon of 5 kg for 2015 we get a total of about 3.2 ton harvest 2015 (we can do this as it is only one real population left). This assessment is of course nonscientific but gives an indication for what is going on, that the slope of the band (the decline of the salmon) in Figure 1 is somewhat good. We expect few small salmon 2019 and a very few medium salmon 2020. Perhaps the harvest in 2016 will be equal to 2015 but the year of 2017 and 2018 will be poor, to say the least. The salmon harvest of 2015 is significant less than the 3 ton the band slope in Figure 1 indicates, the salmon in Surna is collapsing. Surna should be shut for fishing until new conditions for the water power plant give a positive effect on biological diversity and growth in the river. The remaining few salmon are a building brick for future salmon populations and a prodigious Surna. A salmon river can prosper again if we allow it, as well as it can decline. The nature of Surna will recover if we give it a chance with new conditions. The National Salmon River Surna can be a shining example of coexistence of water power and salmon in Norway.


Figure 1. Harvest of salmon and sea trout of Surna years 1989 to 2015 (The River Cooperation’s salmon statistics). Slope of band between the lilac and the turquoise lines is made by hand. Salmon statistics is rose color line and sea trout dark blue. Mean salmon regression is the green line (see Figure 2). The year of 2015 was expected to give a harvest on the lilac line but did not.


Not only the river environment and salmon disappear from the valley with a declining Surna, business opportunities from tourism are discontinued. It is bad business for the municipality to let Statkraft destroy Surna. Surnadal municipality gets about 15 million Norwegian Kroner of tax and fees from the power plant. The proposal from Fiskeraksjonen gives about 7 % reduced power production, corresponding to 1,1 million Kroner less for the Surnadal municipality. A healthy salmon river gives tens of millions krone in return to the valley, money that disappears with a dying Surna. It will not be less working places as the overhaul will be the same for the power station and the maneuvering is already moved to Gaupne in Sogn 1996. The 7 % reduced power production to rescue Surna can be maintained in the yearly variations of power production. It has been an increase of 4 % rain the last years and another 4% is expected the coming 10 years, by itself well compensating for the power loss of Fiskeraksjonens solution of Surna.


2. School example of salmon statistics when a river degrades. Each cycle is about ten years.



Figure 3. Graph from Vitenskapelig Råd for Lakseforvaltning, assessment of the salmon spawning population in Surna (rapport 2015-8b). It gives the impression that the spawning population of salmon is as large as 20 years ago. Compare the River Cooperation’s statistics in Figure 1. Something is obviously wrong.