The site, developed by a company in southeast France, allows holidaymakers on the Mediterranean coast to record any jellyfish sightings they come across. The technology then cross-references the data with satellite observations to register the sightings.
Last weekend, it received a record 10,000 visits per day as visitors to the Mediterranean’s beaches both recorded sightings of the creatures and looked to see if there were many near to where they were hoping to take a dip.
Developed by a company in the French tech hub of Sophia Antipolis, the tracker shows bathers green, orange and red pictograms to highlight the location of jellyfish.
Most sightings are from the coast between Menton and Marseille in France – a popular destination for tourists during the summer season.
Antoine Troullier, an engineer at the company Acri-ST, said sightings had shot up in recent weeks but warned that it was most likely due to more bathers visiting the coastline rather than an explosion of jellyfish.
He told French news website 20 Minutes: “Right now, we have a hundred sightings a day, but quite simply because there are more people going to the water’s edge.”
He added: “Everyone benefits from being informed.”
A number of European countries have noted a rise in jellyfish numbers in recent weeks.
In Spain, authorities have linked higher than usual temperatures to the return of jellyfish to warm waters around Malaga.
There have also been warnings in recent days that the heatwave currently gripping the UK could bring more of the creatures to the British Isles.
Britons have been warned to keep an eye out for giant Portuguese man o’war jellyfish as they head to the beach this weekend, The Mirror reported.
The creatures have an incredibly powerful sting that can cause agony to anyone who gets caught by one of the huge creatures.
The jellyfish can grow tentacles of up to 160ft – equivalent to the size of five double-decker buses.
While sightings in the UK are rare, with just 62 reported in the past year, windy weather and strong tides can wash them up on Britain’s beaches.
However, Mr Troullier argued that the increase in jellyfish numbers was not due to warmer sea temperatures.
He said: “I’m going to bust a myth, these jellyfish like deep, cold water.
“Their proliferation is not linked to climate change, even if it plays a role on their predators, but more to the weather. We are not on the same time scale.”