– You can sit here and watch it grow. Odd Sømme looks out over the Figgjoelva in Rogaland. Here he has been a supervisor for over 20 years. He has seen with his own eyes the plague spreading in the river. The river is known as a good river for salmon fishing, and is popular among fishing-loving Norwegians, including our own King Harald. He has been a faithful guest at the estuary on the Jær coast with a fly rod in hand. But now life in the river is threatened. Odd Sømme keeps a close eye on how the plant reed plague is steadily taking up more space in Figgjoelva. Photo: Arild Eskeland / news Aquatic plant on the wild road Watercress is an alien species that has so far spread to over 100 lakes and rivers in South-West Norway, East Norway and Trøndelag. What is bubonic plague? Watercress is an underwater plant. It grows quickly and can be up to one and a half meters long. The plant is alien to Norwegian nature, and can have a negative impact on the original diversity in the lake. Once bubonic plague has established itself, it is very difficult to get rid of. The plant originally comes from North America, and was first registered in Norway in 1925. All over the world it is considered a problem plant. It is placed in the highest risk class on the Fremmedartslisten, formerly known as the Norwegian blacklist. Plague is most widespread in Eastern Norway, particularly in Oslo-Akershus and Oppland-Buskerud, but is also increasing in Southern and Western Norway. Wasp plague was probably introduced to Europe as a garden and aquarium plant. In Figgjoelva, the plague has led to a thick layer of mud building up at the bottom of the river. The mud and the dense mass growth create problems for fish life. – I don’t think there is a single river mussel left. They are killed by thick layers of mud lying everywhere, says Sømme. Fish and mussels in the river thrive best on stone and gravel bottoms, and will have problems with reproduction as the river looks now. – There is not a single fish that spawns here at the bottom of the river anymore. – Could be part of the solution Even after repeated attempts to keep the water plague away, parts of the Figgjo River are almost overgrown with the long green plant. The plant is always cut, but quickly grows back and is very difficult to get rid of. But a new method can now offer hope. Odd Sømme always cuts the plant, but the reed grows back quickly. Photo: Arild Eskeland / news Together with the Figgjo River Owners’ Association and Søndre og Nordre Sele Salmon Fishing, the Norwegian Hunters’ and Fishermen’s Association will test methods to limit the damage caused by the plague. Also on the team is researcher at Norce LFI, Ulrich Pulg. Now they will try to wash away the layer of mud in the river with the help of a powerful water washer. A powerful water washer will try to wash away the layer of mud in the river. Photo: Odd Rune Kyllingstad / news – It is a gentle method of flushing. Where you can really take care of local conditions, river mussels, spawning grounds and so on, says Pulg. He believes that flushing is a promising method for managing the water plague, without having to make major land interventions. Even if it is not possible to eradicate the wasp plague, Pulg still believes that the measure is sensible. Ole Ulrich Pulg believes flushing is a promising method. Photo: Leif Rune Løland – That’s what you have to do in situations like this. If you have tampered with the river, you have to carry out some kind of maintenance to ensure that both fish and river mussels can live there, but also to get the runoff water out of the watercourse. If you don’t do that, the risk of embarrassment increases. Caused by human intervention It is no coincidence that the bubonic plague appeared in Figgjo. Pulg believes the cause is human intervention in the river. – Water plague is a symptom of things that have changed in the watercourse. Large parts of the river have been dug out and canalized to drain agricultural land. This has resulted in far too low water velocities in the artificial course. In addition, there are many nutrients from agriculture and pollution. Then a foreign species was introduced, the wasp plague. Together, this has led to explosive growth. Pulg believes there are two possibilities for creating better conditions for fish and mussels in Figgjoelven: – The first is maintenance and care. The plant will be removed, hopefully without otherwise damaging the natural environment. This is repeated, perhaps every year. The second is to restore the river as it was. The pollution must be limited and the current in the water increased. This will reduce the growth of water blight and with this also the need for maintenance. Great invasion potential Researchers here calculate that the spread of bubonic plague will only increase in the coming years. Climate changes with higher temperatures lead to a longer growing season and more nutrient supply to watercourses. This provides good growing conditions for smallpox. The species data bank expects that bubonic plague will spread to almost the entire country in the next 50 years, and three times as much area of rivers and waterways will get bubonic plague. Probably only Troms and Finmark escaped. The reed plague is considered to have a particularly high ecological risk, because the reed plant has a large invasion potential in combination with major negative ecological effects, is the assessment of the researchers. – Must do something now Inspector Odd Sømme has a strong desire to clean up the Figgjo river. Not least in the hope that King Harald will visit his favorite river in Rogaland again. – We will have to discuss with him whether he can come back again and use one of his favorite flies, which he got from me. Published 17.11.2024, at 23.06
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The king’s favorite river in Rogaland threatened by bubonic plague – news Rogaland – Local news, TV and radio
