Jellyfish infestation: nuisance and research object

Since mid-June, the fire jellyfish Pelagia noctiluca has multiplied explosively off the coasts of Corsica and the Côte d’Azur, making bathing for holidaymakers on many southern French beaches. The Italian Simone Martini can sing a song about it. It caught him on a beach in Ajaccio, Corsica. “Two weeks later, the sting still hurts me sometimes,” he says of the wound on his forehead.

“Peing on the wound does not help!”
There are many tips to relieve the pain, but oceanographer Fabien Lombard has doubts about most methods: “Peating on the wound certainly does not help,” says the expert from the marine research institute Laboratoire d’Océanographie de Villefranche/ Merel, laughing. But above all, one should not “rinse the affected area with sea water or rub it with sand”.

Squirrel jellyfish shoot tiny harpoons with a poisonous cocktail from stinging capsules attached to their tentacles. “Ailments are blind, so they sting anything they come across to see if they can eat it. They inject neurotoxins to paralyze their prey and enzymes to digest them,” Lombard explains.

Spread slime across the seas
Scientists are concerned about jellyfish for other reasons. In a report published in 2019, the Intergovernmental Panel on Climate Change (IPCC) warned that the spread of jellyfish would lead to “gelification”, i.e. a type of mucosal pollution, in the oceans. Fabien Lombard has his doubts: “We have no reliable measurements showing that there are more jellyfish.” He does admit that “in the 80s and 90s in Villefranche-sur-Mer it was alternately five to six years with jellyfish and five to six years without jellyfish”. But this year it is “already the 25th in a row with jellyfish”.

symptom of overfishing
Lombard, however, cautions against seeing the jellyfish infestation as a problem in itself. Rather, it is a symptom of the overfishing of the seas. For Lovina Fullgrabe of the Corsican marine research institute Stareso, the overfishing of tuna and sea turtles, both of which eat jellyfish, is one of the most plausible hypotheses to explain the increased occurrence of jellyfish.

Jellyfish have been living in the seas for about 600 million years. Science owes some breakthroughs to the cnidarians. For example, in 2008 the Nobel Prize in Chemistry was awarded for the use of phosphorus from jellyfish in the visualization of cell processes, for example in research into Alzheimer’s.

Research object for reproduction in weightlessness
The US space agency NASA uses jellyfish to study reproduction in weightlessness and since 2017 the European Union has been working with the “GoJelly” project to find out how jellyfish can be used in food, fertilization or against environmental pollution.

According to Lombard, jellyfish can be used as feed in fish farming or to maintain soil moisture, for example in viticulture or rice cultivation. The jellyfish’s collagen is sometimes used in diapers or tampons to bind moisture, and in some places even makes concrete more flexible and therefore more earthquake-resistant, says the marine researcher. It is also being investigated how jellyfish can help with the formation of cartilage in the human body. As a last resort, people could still eat jellyfish to limit their numbers. At least that’s what the UN Food and Agriculture Organization (FAO) suggested in 2013.