Holidays “company” with jellyfish in the Greek seas and this year experts predict. The outbreak of purple jellyfish -or Pelagia noctiluca as its scientific name is- in the Aegean has started since October 2020 and if the same pattern prevails we will have to deal with them for another 1.5 to 2 years.
The purple jellyfish are considered one of the most dangerous species of jellyfish in the Mediterranean . Their sting is painful because of the neurotoxin they have, so bathers should be very well informed about what to do in case of a sting.
The outbreak of purple jellyfish in an area was observed before climate change about every 10 to 12 years and lasted a maximum of 4 years (on average 2-3 years). In 2015 until 2018 there was a strong population outbreak of this species in the Corinthian Gulf , in Malta the population explosion of purple jellyfish (Pelagia noctiluca) prevailed from 2018 to 2020, while we saw a reappearance in Malta and January 2022.
This year, they have been observed in various areas of the Aegean and the Ionian , while winter swimmers reported seeing this species of jellyfish in the winter as well. However, their presence increases greatly in summer as its breeding conditions are favored due to the higher sea temperature. Their reproduction is also favored by climate change which raises the water temperature. At the same time, the reduction of the population of fish, which are their hunters, but also the reduction of the population of sea turtles, which is their main hunter, favors the spread of jellyfish.
The purple jellyfish is a pelagic species and lives in tropical waters. It has a maximum length of 10 cm in diameter and the length of the tentacles can reach up to 10 meters. It feeds mainly on sausages, various shellfish, placental crustaceans and fish eggs. The largest natural predators of jellyfish are the tortoise, the loggerhead tern, the tuna, the swordfish and the moonfish. When she is young her color is orange & # 8211; coffee and when it grows up it takes on a bright purple-purple color. The recognition is made by its external morphological characteristics, ie what color it is, if it has dots or stripes on its bell, if its gonads are visible and what shape they have (for transparent jellyfish, such as Aurelia sp.), How are their tentacles in shape and if they have some different colors or stripes on their tentacles or on their bell.
“Every species of jellyfish makes a natural outburst every few years. e.g. the Mediterranean jellyfish (Cotylorhiza tuberculata) erupts every year in August, while the Medusa Compass (Chrysaora hysoscella) has an outbreak every year from March to mid-May. The purple jellyfish (Pelagia noctiluca) had a natural outbreak every 8 to 10 years and their outbreaks lasted up to 4 years maximum. But due to some factors such as e.g. climate change, overfishing, lack of predators, etc. has helped these outbreaks to occur more often and with greater spread “, explains to APE-MPE, Christos Taklis who is a Marine and Conservation Biologist and Manager of the Hellenic Biodiversity Observatory.
Almost all species of jellyfish are found in the deep waters and away from the beaches. But because their movement is passive as they are carried away by sea currents and waves, they depend solely on winds, waves, and especially underwater currents.
“T Most species in their outbreaks, we can see them on the surface of the water or at a shallow depth of centimeters or even 1-2 meters under water. “Usually people see on the beaches in the zone that crumbles or even steps, only the jellyfish that come with the waves, while further even 100 meters or even 200 meters from the beach there are many more jellyfish” , he states in APE -BPE. Regarding the way of protection it states: “There is no total protection. The main tips are to dive with a mask and if there are many jellyfish of some kind that stings like Pelagia noctiluca, to come out of the sea for that day. But a combination of measures can help a lot for all of us to enjoy swimming, such as putting on a thin lycra or neoprene suit to cover most of our body, a mask to see what is happening around us, controlling the winds so that the wind goes in order not to bring the jellyfish out to the beach, we make sure to record the jellyfish and upload them to inaturalist.org (there is also an application for android and iphone phones) to inform the world but also to be informed if there are any jellyfish and always with us a cream for jellyfish.
Symptoms of purple jellyfish stings
swelling, burning as well as sometimes severe dermonecrosis, cardio- and neurotoxic effects , which are particularly dangerous in sensitive individuals.
Symptoms after contact – jellyfish sting can be: Burning pain, often severe redness of the skin, and in some cases the jellyfish imprint appears on part of your skin, nausea, pressure drop, tachycardia, headache, vomiting, diarrhea, bronchospasm, shortness of breath.
In case of systemic symptoms (rare) such as: hypotension, hoarseness, wheezing, generalized angioedema & # 8211; extensive urticarial rash, communication level disorders & # 8211; consciousness, vomiting, it is imperative to transport the patient immediately to the hospital.
Citizens are asked to look at the weather and the winds before going to a beach. It needs to have opposite winds in the direction of the beach (eg if the beach has a view to the south, then to reduce the possibility of jellyfish the winds must come down from the north, so that the ripples it creates drive them away away from the beaches).
If a beach has plankton , it is recommended that citizens avoid swimming, because jellyfish feed on plankton and their urticaria are small, transparent and can reach 10 meters in length.
If there is a serious problem with purple jellyfish on a beach then it is recommended that citizens do not risk swimming and make sure to always have some antihistamine cream with them or some cortisone ointment that can be obtained from any pharmacy.
For no reason should citizens take the jellyfish out to bury them in the sand, due to the fact that the problem is carried out with the possibility of someone accidentally stepping on a nematode, but also because in such large outbreaks as many as the citizens see and to make out there are hundreds or even thousands more in the sea. This is not going to solve the problem.
There are harmless jellyfish
In addition to purple jellyfish, there are others that do not pose a danger to bathers and according to with Mr. Taklis we should not tease them or take them ashore. And it explains why concluding:
« First and foremost reason is that if the jellyfish bite then we transfer the problem to the mainland and if there are outbreaks such as e.g. of the purple jellyfish (Pelagia noctiluca) then we do not achieve anything because a little further in the sea we have millions and billions of jellyfish that trying to take them ashore will break their transparent tentacles in shallow water or on the beach that if we touch them or step on they can sting us again.
Second reason is that some jellyfish like e.g. The Mediterranean jellyfish (Cotylorhiza tuberculata) when it decomposes under the hot sun starts to smell bad within minutes.
Third reason is that they are very useful jellyfish species because they consume phytoplankton and zooplankton in huge quantities. If there is enough phytoplankton (the brown color on the surface of the sea) it creates various problems in the ecosystem but at the same time it spoils the holidays for tourists who do not like to swim in it. While zooplankton are tiny marine organisms, they also include jellyfish regardless of whether a few species are large and we see them. An outbreak of zooplankton again causes us a problem with intense itching in our body and we can not swim. In fact, they are often millions of tiny jellyfish invisible to the eye, since their size is often a maximum of 1 or 2 millimeters and the world has an itch just swimming “.