Threatened by climate change – there may be fewer jellyfish in the south – NRK Culture & Entertainment

Brennmanets lange tråder kan ødelegge badeturen for mange

– There are more jellyfish than a man’s memory, people say, but a man’s memory is not good.

So says researcher at the Institute of Marine Research, Ton Falkenhaug.

Tone Falkenhaug, Research Fellow at the Institute of Naval Research.

Photo: Erlend Astad Lorentzen

Because there are no more jellyfish than in previous years. The number of jellyfish varies from year to year. This means that some years we get jellyfish “invasions”, and headlines that this year will be “jellyfish summer.”

The reason for such large differences from year to year is not known. According to Falkenhaug, there are likely several factors.

Food conditions and temperature may have a significant effect on the number of jellyfish present.

Ocean currents can also create large amounts of jellyfish in a small area, she says, referring to observations about jellyfish in Oslovjord earlier this summer.

May be lower in the south

According to Falkenhaug, the number of jellyfish has remained fairly stable, but changes in the climate may lead to a decrease in the number of red jellyfish.

– The red jellyfish prefers the cooler waters around the Norwegian coast, but as the temperature increases, it can move north, and we can see little of it further south.

Red stingray, or Cyanea capillata, as it is called in Latin, has a life cycle of one year. So it is not only the temperature in the summer months that matters to the residents. In winter, the jellyfish dies, but the polyps, from which the jellyfish comes, remain on the sea floor.

burning jellyfish

Jellyfish can be up to 2 meters long and strands up to 30 meters long.

Photo: Tony Holm/NRK

There is no good news

Although the red jellyfish has brought so many tears and spoiled swimming trips, there is no reason to celebrate a possible population decline.

The red jellyfish has been a natural part of Norway’s ecosystem for millions of years, says Falkenhaug.

Jellyfish have several functions of the ecosystem. It eats plankton, transfers carbon to the sea floor, and is food for many different species.

Does not necessarily mean smaller jellyfish

There is also no guarantee that less red jellyfish in the south means fewer jellyfish.

With warm water, new species that don’t belong here can breed, says Falkenhaug.

An example is the American lobe jellyfish, which reached Norwegian waters with ballast water from the coast off the United States and Canada. Other types such as Klamremanet (Hosts Gonionemus) and Lysmanet (Pelagia Noctiluca) as observed in Norway. None of these species are particularly dangerous, especially compared to the species we find further south in Europe, such as the fearsome Portuguese warship Physalia Physalis.

Blue jellyfish also love warm water, so there may be more of it.

Falkenhaug says they can’t be sure of the number of jellyfish, as they don’t have enough data. It asks people to report to the Marine Research Institute if they see an unknown jellyfish.

Pelagia noctiluca caused great fear in 2013, when large deposits were observed.

Pelagia noctiluca caused great fear in 2013, when large deposits were observed.

Photo: Arne Thorsen/Institute of Naval Research

Rinse it with salt water

If you are unlucky enough to get a burn, the advice is to rinse it off with salt water. It is not recommended to rinse them with fresh water, as this may make the burning sensation worse. Remedial tips such as rinsing with vinegar or urine are not recommended. If you have trouble breathing, you should see a doctor.

Are you afraid of jellyfish? Pia Ve Dalen is a marine biologist and fears jellyfish. Hear her share her fear of strings and her love of the sea with Line Elvsåshagen here.

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Dalila Awolowo

Dalila Awolowo

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