Reportage: Tobias Dahlin Photo: Tobias Dahlin och Jennie Soriano
Text: Amanda Saveland
The lung jellyfish is a large, compact jellyfish that thrives best in warmer waters and is commonly found in the Mediterranean and the North Atlantic. It is completely harmless to humans and has a truly unique characteristic that makes it easy to recognise.
– “The most distinctive feature by far is that they are so distinctly blue. They even have their own unique blue pigment that is found only in this group,” says marine biologist Martin Stjernstedt.
Among other things, he works on validating sightings for Artdatabanken, which is run by the Swedish University of Agricultural Sciences (SLU) and collects observations of various species. Every year, a few lung jellyfish are usually recorded, having been carried northwards by the ocean currents in late summer, but not as many as there have been this year.
‘Usually, you only hear about one or two, but this year we currently have 49 reports in Artdatabanken alone,’ says Martin Stjernstedt.
Nearly 70 sightings have been received
At the same time, there have been significantly more sightings. On Facebook, Havets hus has received nearly 70 sightings recently, and Martin Stjernstedt himself has seen 10 lung jellyfish in Kyrkvik in central Lysekil. This means they have now received well over 100 sightings.
“Some people say they’ve spotted 20 of them on a single beach. So it’s clearly a lot,” says Martin Stjernstedt.
There is undoubtedly something that has happened this year that has caused so many lung jellyfish to drift up to the west coast. But it is currently impossible to determine the cause of this sharp increase.
“It’s like trying to predict next year’s weather based on a single event. It’s not possible,” says Martin Stjernstedt.
Several possible causes
It is in late summer that the moon jellyfish reach maturity in the Mediterranean or out in the Atlantic. Once they have grown large and heavy, they are carried along by the currents that take them northwards, enabling them to travel all the way to Sweden. There may therefore be several explanations for why there have been so many this year in particular.
– It may be that there are huge numbers of them in the Atlantic, and that is why there are so many of them here now. Or it could be that the currents this year in particular are ideal for carrying them in from somewhere where they occur naturally. But it could also be a combination of both, says Martin Stjernstedt.
The trend over time will tell
Another explanation could be linked to a major change in the ocean: namely, global warming, which is causing the oceans to get warmer. This can both affect ocean currents and favour species that thrive in warmer waters.
– A single incident cannot confirm that this is the cause. But if it were to continue happening and we were to see that the lung jellyfish remain this abundant for several years to come, or that their numbers are increasing slowly but surely, then that would certainly be a sign of it, says Martin Stjernstedt.
Every year, there are usually isolated reports of lung jellyfish sightings on the Swedish west coast, but this year there have been significantly more sightings than usual.
´There’s no doubt it’s a huge number,´says marine biologist Martin Stjernstedt at Havets hus in Lysekil.
The lung jellyfish is a large, compact jellyfish that thrives best in warmer waters and is commonly found in the Mediterranean and the North Atlantic. It is completely harmless to humans and has a truly unique characteristic that makes it easy to recognise.
´The most distinctive feature by far is that they are so distinctly blue. They even have their own unique blue pigment that is found only in this group,´ says marine biologist Martin Stjernstedt.
Among other things, he works on validating sightings for Artdatabanken, which is run by the Swedish University of Agricultural Sciences (SLU) and collects observations of various species. Every year, a few lung jellyfish are usually recorded, having been carried northwards by the ocean currents in late summer, but not as many as there have been this year.
‘Usually, you only hear about one or two, but this year we currently have 49 reports in Artdatabanken alone,’ says Martin Stjernstedt.
Nearly 70 sightings have been received
At the same time, there have been significantly more sightings. On Facebook, Havets hus has received nearly 70 sightings recently, and Martin Stjernstedt himself has seen 10 lung jellyfish in Kyrkvik in central Lysekil. This means they have now received well over 100 sightings.
´Some people say they’ve spotted 20 of them on a single beach. So it’s clearly a lot,´ says Martin Stjernstedt.
There is undoubtedly something that has happened this year that has caused so many lung jellyfish to drift up to the west coast. But it is currently impossible to determine the cause of this sharp increase.
´It’s like trying to predict next year’s weather based on a single event. It’s not possible,´says Martin Stjernstedt.
Several possible causes
It is in late summer that the moon jellyfish reach maturity in the Mediterranean or out in the Atlantic. Once they have grown large and heavy, they are carried along by the currents that take them northwards, enabling them to travel all the way to Sweden. There may therefore be several explanations for why there have been so many this year in particular.
´ It may be that there are huge numbers of them in the Atlantic, and that is why there are so many of them here now. Or it could be that the currents this year in particular are ideal for carrying them in from somewhere where they occur naturally. But it could also be a combination of both, ´ says Martin Stjernstedt.
The trend over time will tell
Another explanation could be linked to a major change in the ocean: namely, global warming, which is causing the oceans to get warmer. This can both affect ocean currents and favour species that thrive in warmer waters.
´A single incident cannot confirm that this is the cause. But if it were to continue happening and we were to see that the lung jellyfish remain this abundant for several years to come, or that their numbers are increasing slowly but surely, then that would certainly be a sign of it, ´ says Martin Stjernstedt.
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