The invasive silver-cheeked pufferfish (Lagocephalus sceleratus) has spread through Greek waters and is now posing a serious threat to fisheries, marine ecosystems, and public health if consumed.
Stefanos Kalogirou, Associate Professor at the Agricultural University of Athens, told Greek Reporter that the pufferfish can now be found across a wide geographical range in Greece, “from the southern Aegean to the northern Aegean and from the southern Ionian to the northern Ionian.”
The pufferfish, scientifically known as Lagocephalus sceleratus, was first recorded in the Mediterranean in 2003 off the coast of Turkey. Greece recorded its first sightings in 2005 off Rhodes and Crete, according to Kalogirou. Since then, the species has expanded rapidly. It belongs to the Tetraodontidae family, a group whose name refers to the four fused teeth, two in each jaw, that give these fish their powerful bite.
Toxic pufferfish invades Greece’s waters
Kalogirou explained that there are around 130 species of pufferfish and related tetraodontids worldwide. Six have appeared in the Eastern Mediterranean, including Lagocephalus sceleratus. The danger comes from tetrodotoxin, one of the most powerful marine toxins known. The toxin is found mainly in the liver and reproductive organs of the fish, although Kalogirou noted that it can also be present in muscle tissue, the part humans may attempt to eat.
“Tetrodotoxin causes muscle paralysis, blocks the nervous system, and can lead to death,” Kalogirou said in speaking with Greek Reporter. The main threat, however, does not come from contact with the fish. It comes from its consumption.
“The toxin affects humans only when they consume the fish, not if the pufferfish injures them with its teeth,” Kalogirou said. “The highest concentration of the toxin is in the liver and not in the mouth or teeth of the Lagocephalus.” That distinction matters because the fish’s strong teeth can still cause injuries. Kalogirou stressed that a bite can create a wound, but the toxin does not transfer through the teeth.
What swimmers need to know about pufferfish bites
For swimmers, the main risk from a bite is physical injury rather than poisoning. The teeth of the silver-cheeked toadfish are powerful enough to crush shells and damage fishing gear, so a bite can be painful and may require medical attention. Kalogirou made clear, however, that a bite should not be confused with tetrodotoxin poisoning.
“The bite has nothing to do with the toxin,” he told Greek Reporter. “The toxin is not transferred through the teeth.” Still, that does not mean people should approach the fish. Kalogirou said the species is usually searching for food, which is why swimmers and divers should avoid any interaction if they see it in the water.
Scientific reports suggest that bites by Lagocephalus sceleratus are an emerging but still uncommon public-health concern in the Mediterranean. The clearest documented case describes an eight-year-old girl in southern Turkey who suffered severe finger injuries, including traumatic amputation, after being bitten while swimming. Another medical report from Turkey describes prolonged inflammation after a suspected pufferfish bite.
Broader studies and reviews have collected additional bite reports from countries including Turkey, Greece, Cyprus, Libya, and Syria. However, many of these accounts come from interviews, medical notes, or media reports rather than formal clinical case studies. Overall, the evidence shows that the species can injure swimmers and fishers, although verified scientific documentation remains limited.
If a swimmer is bitten, the immediate concern is the wound itself. The person should clean the injury, seek medical care if the bite is deep, and monitor the area for infection. The far greater danger remains accidental or deliberate consumption of the fish.
European legislation prohibits fishery products from poisonous fish families such as Tetraodontidae from entering the market for human consumption. That ban reflects the seriousness of the toxin and the risk of fatal poisoning.
Why eating Silver-Cheeked pufferfish is so dangerous
The real public health danger comes if the fish is eaten. Unlike ordinary seafood poisoning, tetrodotoxin poisoning can be extremely serious, because the toxin affects the nervous system and can lead to paralysis.
Kalogirou stressed that the fish must not enter the food chain. The toxin can be present in parts of the fish that people may attempt to consume, which makes the species dangerous even if it is handled like an ordinary catch.
For the public, the warning is clear: the fish should not be eaten under any circumstances.
A growing problem for Greek fishermen
Beyond the danger it poses to public health if eaten, the invasive fish has also become a serious problem for fishermen across Greek waters.
Kalogirou said the species damages fishing equipment, including longlines and catches, as it attacks prey and tears through nets and gear. The fish grows quickly, develops significant biomass, and has increasing energy needs as it gets bigger.
Its diet includes shells, octopus, and cuttlefish, which creates direct pressure on species that matter economically to Greek fisheries.
An earlier study by Kalogirou in Mediterranean Marine Science examined the species around Rhodes and found that Lagocephalus sceleratus feeds mainly on invertebrates and fish. The study also showed that larger individuals tend to shift toward mollusks, including commercially important cuttlefish and octopus.
Based on study findings, half of the individuals reach maturity at around 14 inches (36 cm). It was also found that sandy areas are vital for younger fish, while larger reproductive adults tend to prefer Posidonia oceanica seagrass habitats. Those traits help explain why the species has become so difficult to control. It thrives in coastal habitats, grows quickly, feeds aggressively, and competes within ecosystems that already support local fisheries.
Greece’s pufferfish among the Mediterranean’s most invasive species
Lagocephalus sceleratus is considered one of the most invasive alien species in the Mediterranean. Kalogirou told Greek Reporter that the silver-cheeked pufferfish ranks among the one hundred most invasive species in the region. The fish has attracted attention not only due to its toxicity but also because of its ecological and economic impact. Its presence affects fishermen, consumers, fish markets, and marine biodiversity.
The Mediterranean Marine Science study described the species as a pest for fisheries and a potential threat to biodiversity, citing its abundance in coastal fish communities and its ecological and social impacts. For Greece, the problem is no longer limited to isolated sightings in the southeastern Aegean. The fish has expanded far beyond Rhodes and Crete and now appears across many of the country’s waters.
According to Kalogirou, the issue demands urgent attention because the species harms fisheries while also creating a public health risk if people attempt to consume it. “It is a problem that must be addressed,” he told Greek Reporter, noting that the pufferfish causes major damage to nets and other fishing equipment.
Why safe pufferfish disposal and public awareness matter in Greece
Managing the species is also complicated by the fact that landed fish cannot be treated as ordinary catch. Kalogirou maintained that once fishermen remove the species from the sea, proper handling and disposal need attention because the fish is toxic. That means disposal should follow safe waste-management procedures. In some cases, this may involve appropriate facilities such as waste incineration sites so that toxic material does not create further risks after landing.
The issue is also linked to ongoing European research. The Horizon Europe project MECCAM, which focuses on climate adaptation and mitigation in European fisheries, includes Greece as a case study and lists silver-cheeked toadfish among the species relevant to small-scale fisheries.
Population control through targeted depletion fishing may partly reduce the problem, Kalogirou said, but it is not a complete solution on its own. Public awareness remains essential, especially so that people are informed about the risks of consumption of the particular fish and the necessity to avoid coming into contact with it in the water.
He also noted that invasive species populations may eventually decline or stabilize because of competition with other species, lack of food, fishing pressure, pathogens, or a combination of these factors. “Invasive species usually follow a boom-and-bust process, increasing rapidly and then being reduced and stabilized,” Kalogirou said. “But this can take years.”
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