The matter summed up: The increased occurrence of pearl whiting along the Norwegian coast has led to damage to farmed fish in several places in the country. The jellyfish have found their way into the breeding facility and have caused death and damage to the fish. Nordlaks, Salaks and Grieg Seafood are among the farms affected. Perlesnormaneta can be up to 30 meters long and can penetrate breeding cages, where it can harm the fish with its nettle poison. There are still large gaps in knowledge about the pearl standard and the consequences for farmed fish. Researchers are now working to gain more knowledge about the problem. The summary is made by an AI service from OpenAi. The content is quality assured by news’s journalists before publication. Lately, there have been reports of an increase in the occurrence of pearl seabream along the Norwegian coast. And now the jellyfish has found its way into the breeding facility. Farmed fish in several places in the country have been damaged and had to be killed because of the jellyfish. This has happened, among other things, in one of Nordlaks’ facilities. – It is extremely serious and tragic, says Heidi Torkildson Ryste, head of marketing and communications. On Monday, it was reported about dead salmon in two cages at Nordlaks’ facility called Elgen in Kasfjorden outside Harstad. – We send out a fish health biologist with us to investigate and report it to the Norwegian Food Authority. All the dead salmon were picked up, and together they had to slaughter 12,000 fish in fear that the jellyfish would attack more. – As we know that there have been jellyfish there, we were afraid that it would lead to more suffering and mortality. – Powerless IntraFish reports that Salaks and Grieg Seafood have also had the dreaded jellyfish enter their facilities in recent weeks. To the online newspaper, managing director of Salaks, Odd Bekkeli, says that they lost over 5,000 salmon in one week at their plant in Dale in Harstad municipality. – We ourselves feel that we are a bit powerless, says Bekkeli. At the Institute of Marine Research’s research station at Austevoll, they have picked up around 4,000 fish that were either dead or dying. Photo: Kjetil Stensland At the Marine Research Institute’s own facility in Austevoll municipality in Western Norway, they were also visited by jellyfish. – Over the course of the night to Monday, pearl sea otters came towards the facility, and we saw that fish had been injured after close contact, says research leader Lars Helge Stien. Out of concern for the welfare of the fish, they had to kill the most weakened fish. In the course of three days, they picked up around 4,000 fish that were either dead or dying, according to the researcher. The fish is suffocated Perlesnormaneta is a colony made up of many small individuals. Some of these individuals have strong nettle venom to protect the colony and obtain food. Jellyfish can be up to 30 meters long. And due to waves, turbulence and physical barriers, it can break up into small pieces, and can therefore penetrate breeding cages. The Perlesnormanet is a colony made up of many small individuals. Photo: Rudolg Svensen / Stavanger museum – When the jellyfish hits the wall of the net, it can be split into smaller pieces from which it is difficult for the fish to swim away. The tentacles of the Perlesnormaneta have nettle cells that trigger a spike that injects nettle poison when they hit the fish, says Stien. This can cause damage to the skin, eyes and gills. – Long strips of damaged skin and obvious wounds can occur. The eye can get obvious wounds and bleeding. But the gills are also particularly exposed to bleeding and damage. In the worst case, this can lead to the fish being suffocated, says the researcher. Need more knowledge about the problem We are aware of two previous episodes where jellyfish have led to increased mortality in breeding facilities. In 1997, 10–12 tonnes of salmon died at two facilities in Øygarden and Fedje in Vestland. In 2001, 600 tonnes of fish died. – Maneta was a problem last year, and it seems that she is a bigger problem this year. If this becomes an annual phenomenon, it will become a major problem for the Norwegian farming industry, says the researcher. This perlesnormaneta, which is estimated to be four meters long, was observed outside Sveio in Vestland. Video: Åge Wee There are still large gaps in knowledge about the pearl standard and the consequences for farmed fish. Therefore, marine researchers are now using the incident at the research station to acquire more knowledge. – Now we are taking samples of the gills of the salmon, to see how the damage has developed, and whether the respiration of the fish has been affected. We also take samples of the eye, to see if the vision has been damaged, and of the skin, to see the extent of burn damage. According to Stien, the number of messages about this jellyfish has increased. This year they have had over a thousand observations sent to them. – We are afraid that this may be a problem that may become more frequent in the future, so then we must acquire knowledge of how it affects the fish and, in the long term, how we can possibly find mitigating measures.
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Perlesnormanet kills and injures farmed fish along the coast – news Nordland
