The non-native lionfish has become increasingly common in parts of the Mediterranean in recent years, threatening local ecosystems and endangering humans through their poisonous spines.
Professor Jason Hall-Spencer, biologisYou sailor, first saw a lionfish off the coast of Cyprus in 2016. It was just an individual, but the species - which produces around 2 million eggs each year and lack of natural predators in their new environment - quickly took hold. "In some places I 've seen 40 in a single dive " said Hall-Spencer of Plymouth University.
To combat the growing numbers of lionfish, Hall-Spencer and his fellow researchers at the University of Plymouth and the Marine Research Laboratory and Environmentalists of Cyprus worked with specially trained divers and citizen scientists to coordinate withdrawal events and investigations over six months. The collaboration is part of the EU-funded ReLionMed project.
"[The lionfish] are found at shallow depths where you can swim - us them. let's see in 1or 2 meters deep - and they can give you a really nasty sting because their fins are filled with venom, "Hall-Spencer said.
Although 'There are records of lionfish in shallow water, they mainly cling to deeper water and therefore pose an increased risk to the public health of divers, said Periklis Kleitou, senior author of the study published in Aquatic Conservation . "As they expand [their range], we hope they do not invade coastal areas, where there are a lot of tourists.
But lionfish cause more problems than the threat of a painful sting. Invasions of the species in other parts of the world have shown that carnivorous fish can quickly colonizeer reefs and reduce biodiversity in the area, a problem for the reef ecology and local fishermen.
Native to the warm, tropical waters of the 'Indo-Pacific, the first official sighting in Europe was in 2012 and off Cyprus in 2014. Warming oceans and expansion of the Suez Canal played a role in the lionfish invasion from the Red Sea to the eastern Mediterranean. They are spreading rapidly and some have reached Tunisia and Italy.
Now research shows that removing fish has the potential to help control its populations.
Hall-Spencer said lionfish were seen in marine protected areas (MPAs), set up to save organisms nativeof the Mediterranean. "What [MPAs] actually do is protect these invasive species - they provide refuges - and that is a concern," he said.
"Eradication is beyond the scope of the question," said Dr Louis Hadjioannou, a research biologist jointly affiliated with the Marine Institute and maritime research center in Cyprus and at the Enalia Physis research center. "We are talking about controlling populations " he said.
The team took five samples with specially trained volunteer divers who have caught between 35 and 119 lionfish per day at each of the three protected marine sites surveyed off the coast of Cyprus.
The research also used citizen science to monitor the number of lionfish at study sites after sampling. A combination of citizen science reports andMonitoring of fixed transects revealed that lionfish abundance declined after collection.
Recolonization by lionfish occurred at different rhythms, which the researchers attributed to connectivity with neighboring reefs. One problem is that lionfish can be found up to 100 meters below the surface, a depth far exceeding the limits of recreational diving.
"This means that there is a lionfish reservoir in inaccessible areas," Hadjioannou said. These fish can reach the area that was just kidnapped and repopulate.
The lionfish monitoring in the study took place on a short period. Longer-term studies are needed to determine if removals can be a long-term solution, allow for better timing of events, and help identify locations totarget for the best results.
Researchers identify the need for a multi-faceted approach, including advocating for enhanced protection of large predatory fish that may occur. feeding lionfish and encouraging local fishermen to catch them.
Indeed, visitors to Cyprus may soon see lionfish on the menu. We can already see it in fish markets and in a few restaurants. As the market grows, it is hoped that their value will increase. The project is also cooperating with markets to promote the sale of jewelry made from lionfish fins.
"With climate change, we "Expect lionfish to invade parts of the western Mediterranean," Kleitou said, and with the fish already widespread in other parts of the southeastern Mediterranean, "the goal long term is ccontinue to transfer our knowledge to their neighboring countries. ”
We must also work to prevent further invasions, said Hall-Spencer. He described the Suez as a "severed artery " that "bleeds all these fish and other species, including viruses and bacteria, into the Mediterranean ".
" What really needs to happen is some kind of biosafety check, "he added, and suggested using desalination plants that produce very salty wastewater. and put them in the Suez Canal. "I think it's going to take international coordination and probably international funding to put this biosafety in place," he said.