– It started in September. We have now received many reports that some of them have been observed along the coast, says researcher Tone Falkenhaug of the Institute of Marine Research.
Autumn has provided a sharp increase in the number of pearl-trawl sightings along the coast.
There were many sightings, especially in western Norway and in Trøndelag. The researcher says that jellyfish have been spotted almost along the entire coast.
Jellyfish burn in the same way as regular jellyfish, and are especially dangerous to farmed fish, Falkenhaug says.
When this long colony hits a physical object, like a fish net, it breaks into smaller pieces. Then it passes through the nets into the cage. But it burns with the same force even if it is atomized.
Like a small community
– This is a kind of colony jellyfish. This means that there are many individuals living in a colony, with each individual specializing in different tasks. The colony forms a long, pearl-like chain, Falkenhaug says
In other words, jellyfish is not a single creature, but a colony of many small individuals. Falkenhaug says that individuals must work together to survive. They have different tasks in the colony, and together they form a small community in a way.
– They are so specialized that they depend on each other. Some are tasked with hunting food, while others are responsible for reproduction. Still others ensure that the colony has momentum and swim forward, and still others to float. So he is a wonderful creature.
600 tons of fish died
In the past two years, natural pearls have led to mass deaths of farmed fish. In 1997, the species killed 12 tons of salmon, while up to 600 tons died in 2001, according to the Norwegian Institute for Marine Research.
The gills on fish are particularly concerned. But we can hope that no such incidents will happen this year, Falkenhaug says.
Wild fish can probably avoid jellyfish by swimming away, but farmed fish can’t, as they have slightly less room to frolic.
In the ‘Dugnad for the sea’ portal, the applicant writes that jellyfish have been seen in several places around Vannøy and outside of Tromsø. On the online portal owned by the Institute of Marine Research, everyone can record their observations of life at sea.
At Rana in Nordland, many Norman pearls became notice Just a few hundred yards from the Bucktowden Breeding Facility.
Tom Eirik Aasjord, managing director of Nova Sea, which owns the breeding facility in question, says they’re prepared if the jellyfish come dangerously close.
– We have detailed contingency plans for such threats. If jellyfish enter the cage, or we detect them before they reach the facility, we will be able to move fish temporarily, for example.
– We can also take other actions if there are many threats nearby.
Aasjord is not immediately concerned, despite noticing a jellyfish in the plant.
– We are monitoring the situation, he says.
It comes with ocean currents
However, it has been a long time since jellyfish caused serious damage to farmed fish.
Last year at the same time, a similar pattern was seen with several observations.
– It is believed that it is associated with the flow of water masses of the Atlantic Ocean. This is a species widespread in many oceans of the world, especially in the Atlantic Ocean. Perhaps jellyfish follow the warm ocean currents that come along the coast, Falkenhaug says.
But why there are so many in some years and less in others is unknown.
Falkenhaug has a clear appeal for people who have to observe jellyfish:
– Report it for “Dugnad for the sea”. There you can report observations of various interesting objects along the coast.
“Explorer. Unapologetic entrepreneur. Alcohol fanatic. Certified writer. Wannabe tv evangelist. Twitter fanatic. Student. Web scholar. Travel buff.”