These are the most common jellyfish in Norway
If you are going to spend time by the sea this summer, the chances are high that you will hit a jellyfish or two.
– Exactly this year there have been a lot of stingrays and glass jellyfish along the coast in southern Norway, based on what the public has reported, says researcher Tone Falkenhaug.
You may have noticed some years there are a lot of stingrays in the sea, while other years there is almost nothing. Exactly why this is the case, researchers are not entirely sure.
– We know quite a bit about what is the cause of such jellyfish blooms and where the bloom takes place, says Falkenhaug.
Jellyfish and blue jellyfish
The red stingray (Cyanea capillata) is the most common jellyfish along our coast. It often occurs in large quantities every year.
The stingrays can be up to meters in diameter, and it can have 30 meters long threads. It does not thrive in too hot water, and if it gets above 20 degrees in the sea, it pulls further into the water. But since all jellyfish operate with the water currents, they will come to the surface again if there is wind and upwelling of colder water.
The Blue Jellyfish (Cyanea lamarchi) is rarer than the red, and is found along the coast in southern Norway. It is also more heat-loving than the red one. In recent years, the blue stingray has become more common, and it occurs further north than before.
The toxin in the two jellyfish species is about the same, but the blue jellyfish are smaller and also have fewer stinging threads than the red ones.
The glass jellyfish does not burn the skin
Another bluish jellyfish that we can see in large numbers every year is the glass jellyfish (Aurelia aurita). The glass jellyfish is a large, almost transparent jellyfish and can grow up to 40 centimeters in diameter. It lives in most sea areas and is common along the Norwegian coast.
The glass jellyfish does not normally burn humans, because the amount of nasal poison is too small. The jellyfish has four distinct and distinctive rings on the surface. These rings are the jellyfish’s reproductive organ, and here the female jellyfish produce eggs and the male jellyfish produce sperm.
Both the glass jellyfish and the fire jellyfish thrive best in the upper layer of the ocean, since that is where the food is. Jellyfish are predators and eat planktonic crustaceans, other jellyfish and fish fry.
Lung jellyfish, crown jellyfish and compass jellyfish
Two other species that are observed regularly in Norway are the lung jellyfish and the crown jellyfish.
Lung Jellyfish (Rhizostoma squid) is found in the southern North Sea and is a rare guest along the Norwegian coast in late summer. The jellyfish is milky white with a blue-violet edge on the bell.
The lung jellyfish lacks tentacles and does not burn. It captures food by sucking zooplankton in through small pores. It can be up to 50 centimeters in diameter, and it can be so large and heavy that you can not get it on board if it is caught in a grenade.
Crown Jellyfish (Periphylla periphylla) is a deep-water species that thrives in Norwegian fjords. It can occur in high densities in some areas, and can take a trip to the surface at night. The color is characteristic deep red to violet, and it has thicker stinging threads than other jellyfish.
Compass Jellyfish (Chrysaora hyoscella) is rarer in Norway, but is still observed regularly. The compass jellyfish have V-shaped stripes that extend from the center, almost like a compass.
Unlike many of the other jellyfish, the compass jellyfish is hermaphrodite, ie bisexual. The smallest individuals are males, but as the jellyfish grows larger, the jellyfish changes sex and becomes female.
The staple jellyfish and the hollow skirt jellyfish
Two other jellyfish that have been observed in Norway in recent years are the colony jellyfish and the staple jellyfish.
Staples (Gonionemus vertens) got its name from the way it clings to seaweed. In recent years, several cases of jellyfish along the Norwegian coast have been reported.
The staple jellyfish is a small stinging jellyfish that has a strong gift that is powerful if you get it on the skin. It is a few centimeters in diameter, shaped like a plate, and the gonads form an orange cross. It lives inside seaweed and eelgrass and uses its tentacles to hold on.
Colonimaneten (Physophora hydrostatica) is also a rarer sight in Norway, but has been observed more often in recent years.
– It has been named the hollow skirt jellyfish, because of how it looks, Falkenhaug says.
The hollow jellyfish usually lives at depths of 200 to 1200 meters and is widespread in all oceans. Currents and storms can sometimes bring art to the surface and to our shores.
See pictures of several jellyfish:
American lobster jellyfish
– American lobster is another species that people often observe and report in, says Falkenhaug.
American lobster jellyfish (Mnemiopsis leidyi) has an oval, bell-shaped and transparent body. It belongs to the animal group «rib jellyfish», which in contrast to nettle animals such as fire jellyfish and glass jellyfish do not have nettle cells. The lobe jellyfish cannot sting or sting, but uses adhesive cells to capture zooplankton.
The American lobster is an alien species in Norway and actually belongs along the east coast of the United States. It is said to have accompanied ballast water in cargo boats and was found in the Black Sea for the first time in the 80s. In Norway, it was first discovered in 2005 and is now a common art along the coast.
The American lobster is multiplying very rapidly, and the population can multiply in a few weeks. The jellyfish has a large intake of zooplankton, but can also tolerate long periods of food shortage. Then they erode their own body and shrink in size.
The American lobster jellyfish can have a major impact on the ecosystem and is therefore listed in the Species Data Bank’s alien species list as a species with “very high risk”.
Other rib jellyfish that are common to see, and which naturally belong in Norway, are the lobe jellyfish (Bolinopsis infundibulum), sea buckthorn berries (Pleurobrachia pileus) and cucumber jellyfish (Beroe cucumis).
Have you seen an unusual jellyfish?
Have you seen large numbers of any jellyfish? Or have you found an unusual jellyfish? Then our researchers would like to hear from you.
Report your finding on dugnadforhavet.no.