2024-03-31 17:11:01
The Rhopilema nomadica jellyfish, after managing to disrupt tourism and fishing in Israel, is headed for Greek shores
The presence of the tropical jellyfish Rhopilema nomadica on the Greek coast since mid-March is unprecedented, causing concern about what will happen to its population. In particular, around 100 to 200 jellyfish have been observed on several beaches of Rhodes, close to the coast. Experts point out that the increase in sea temperature, due to climate change, creates favorable conditions for the appearance of such outbreaks in jellyfish populations.
This particular species is familiar to Israel, as it has “colonized” most Israeli beaches from north to south, while according to scientists it seems that several of them manage to survive the winter as well.
Also known as the nomadic jellyfish, Rhopilema Nomadica has a hemispherical shape, a transparent bluish color and a diameter of usually 30-40 centimeters although it can reach 1 meter.
It also has eight tentacles with filamentous cysts, i.e. small stings with poison, which if they come into contact with the skin cause intense pain, burning sensation, itching and irritation of the area.
The sea heatwaves that occurred last year as well as the general increase in the temperature of the Mediterranean seas allowed this particular type of jellyfish to spread to our country.
According to Stelios Katsanevakis, a professor at the Department of Oceanography and Marine Biosciences with research activity in marine ecology, “these jellyfish are present in very large concentrations on the coasts of Israel, with the result that every year beaches are considered unsuitable for swimming. Fishing is also hindered, as when the nets are filled with huge quantities of jellyfish, their poison is released and the rest of the fish are considered unfit for sale.”
Excitement in Greece as well
The professor predicts that such outbreaks of this particular jellyfish will also be observed in Greece, initially in the Dodecanese and Crete, however it is difficult to estimate when this will happen.
“It is very difficult to predict how their journey will develop because it is something unprecedented. However, we expect that we will have a population boom for this species as well, as happened with the purple jellyfish. Its population boom is expected to create a problem for tourism, so I think we should think about what measures we can take to protect bathers as well”, he explains.
Rising sea temperatures are changing the marine ecosystem
The colonization of Rhopilema Nomadica towards the Greek coasts, however, did not catch the experts by surprise, as if one observes what is happening on the coasts of Israel, Lebanon and Syria (Levantini Basin) one will understand what is going to happen on our own coasts in the coming years due to of climate change.
“Based on climate models, the conditions that prevail in the Levantini Basin, after a few decades will prevail in the southern regions of our country. There are already many local extinctions of indigenous species (gastropods, sea snails, mussels, oysters and fish), while at the same time the thermophilic species of the Red Sea that have arrived from the Suez Canal are thriving. So the catches of the fishermen there are 3/4 foreign species and only 1/4 indigenous”, the professor points out.
Alien species in the Greek seas
Harehead (4 species) LionfishPlototus Lineatus
At the same time, our country has begun to see changes in its marine ecosystem both due to the increase in sea temperature and due to the arrival of alien species in its seas.
According to WWF research, anchovies and sardines, among the most commercial fish in Greece and the Mediterranean, are seriously affected by the climate, threatening the livelihood of coastal fishermen.
For his part, Mr. Katsanevakis notes that in addition to fish, marine flora is also threatened. “On the reefs of the Greek seas there are forests of macroalgae, which have the role that forests have in the terrestrial environment. With the arrival of species from the Red Sea, such as the black sandpiper, these reefs are being deserted, resulting in the loss of an important part of the ecosystem.”
Administrative measures
The professor notes that in our country no management measures have yet been taken to control the population of alien species, however the scientific community is already considering proposals in case it becomes necessary.
“For example with lionfish, measures that have been proposed to reduce the population involve promoting targeted fishing for its consumption, as it is edible. Regarding the poisonous sea bass, what is happening now in Cyprus is that the state is subsidizing its fishing with the aim of reducing its population”, he concludes.
Instructions in case of a sting from the jellyfish Rhopilema nomadica
Remove the tentacles or other remnants of the jellyfish, using a plastic card, tweezers, a stick or a plastic shovel Do not touch the jellyfish with bare hands Rinse with sea water, but do not rub the area. We do not use fresh water.We do not cover the area with bandages.We do not use medicinal preparations without medical advice. coast during peak periods.
Source kathimerini.gr
Sophia Christou
Photo: [Rhodes Aquarium – Hydrobiological Station – HCMR/Facebook]