High doses of copper are harmful to marine life, the researchers believe. Nevertheless, 1,539 tonnes were in use in Norwegian aquaculture facilities at the last count in 2020. – In any case, 1,000 tonnes of environmentally harmful copper are released from the aquaculture facilities every year. In comparison, a net washing plant on land is only allowed to discharge two kilograms per year. We are worried, says researcher at the Institute of Marine Research (HI), Bjørn Einar Grøsvik. Researcher Bjørn Einar Grøsvik at the Institute of Marine Research. Photo: Christine Fagerbakke / Marine Research Institute He is behind a new report commissioned by the Norwegian Directorate of Fisheries. Copper oxide is used as an impregnation in many breeding facilities. This should prevent, for example, mussels from growing on the nuts. This ensures the flow of water through the cages, and cleaning fish eat salmon lice instead of grazing on what grows on the nuts. But the environmental movement wants a ban. Leader of the Nature Conservation Association, Truls Gulowsen. Photo: Marte Iren Noreng Trøen / news – It is shocking that this is still legal. Copper was banned as bottom material in boats many years ago, says leader of the Nature Conservation Association, Truls Gulowsen. Kills important organisms According to the report, the risk of emissions and destruction is greatest in Rogaland and Vestland, where the industry is large. Monitoring shows increased copper levels in bottom masses in several fjords in Vestland in the period 2018–2022. HI has collected and analyzed samples of bottom sediment around aquaculture facilities in Vestland, both in the immediate area and further away from the facilities. – The most sensitive species on the bottom will be able to die from excessive doses. The larval stage of aquatic organisms are also sensitive. We will have a poorer species diversity, says Grøsvik. Laboratory tests also indicate that mussels can suffer internal damage from copper. – Preliminary analyzes show changes in the digestive glands of the shells that have been close to copper. The shells look normal on the outside, but we see damage on the inside at high copper concentrations. But this has not been analyzed completely. Preliminary tests in the laboratory show internal damage to mussels that have been exposed to large amounts of copper. Photo: Christine Fagerbakke / Institute of Marine Research Many tests alternatives The farming industry is now testing substances that can replace copper. – Copper has been the most effective anti-fungal agent. But we are now seeing a sharp decline in the use of copper in parts of the country, and there have been other types of biocides that can be used, says Trude H. Nordli, head of environment and health at Seafood Norway. Trude H. Nordli is head of environment and health at Seafood Norway. Photo: Oddmund Haugen / news The association has over 800 member companies in the fisheries and aquaculture industry, and is now working with a guide on the use of copper-containing nuts. The breeders themselves have an interest in finding replacements. – It is absolutely crucial that the organic waste under the cages is converted. A lot of copper will be able to slow down that process. In the worst case scenario, the location can no longer be used, says Nordli. Engineer Ann-Kristin Olsen and senior engineer Agnethe Hertzberg on a research trip to collect samples for the copper project. Photo: Christine Fagerbakke / Institute of Marine Research Worse with flushing When the facilities are flushed, copper emissions increase considerably. An impregnated circular cage with a diameter of 50 meters can have as much as 400 kilograms of copper on it. Something “bleeds” out continuously, but the biggest emissions occur when the note is flushed. Then, in the worst case, around 80 kilograms can be flushed straight away, says researcher Bjørn Einar Grøsvik. – Should the use of copper be banned? – Measures should be taken. One possibility is to consider a ban on flushing. More needs to be done to find replacement substances that are not harmful, says Grøsvik. The use of copper in the aquaculture industry is regulated by the Aquaculture Act. It states that facilities must be operated in an environmentally sound manner. Special care must also be taken to avoid chemicals escaping into the environment. The head of the Nature Conservation Association believes this is not good enough. – We cannot have an industry that is based on the spread of environmental toxins in Norwegian fjords, says Truls Gulowsen. The report has been commissioned by the Directorate of Fisheries. – We have a working group that works to get an overview of locations with high concentrations of copper in the seabed. The report will be an important tool for the group. Possible measures will be assessed in consultation with the Norwegian Environment Agency, says senior adviser Stian Ervik Kvalø in an e-mail to news.
ttn-69
Copper emissions from fish farms worry scientists – can harm mussels – news Rogaland – Local news, TV and radio
