Two swimmers were left bleeding in separate incidents along Italy’s Cilento coast this week, raising questions about what exactly is lurking beneath the surface of one of the Mediterranean’s most popular holiday destinations.
The attacks occurred just days apart near the seaside towns of Pioppi and Palinuro, in Italy’s Campania region. Both victims suffered deep bite wounds to their calves severe enough to require medical treatment, with one tourist being hospitalized after significant blood loss.
Lifeguards responded immediately in both cases, but neither victim was able to identify the animal responsible. While social media quickly filled with speculation about sharks, marine experts say the evidence points elsewhere.
What Happened?
The first incident involved a 55-year-old Swiss tourist swimming near Pioppi. According to local reports, he suddenly felt a sharp pain in his calf before discovering a deep bite wound. Because he was taking anticoagulant medication, the bleeding became significant and he was transported to hospital.
Only a few days later, a 76-year-old swimmer was bitten under remarkably similar circumstances near Saline Beach in Palinuro. Lifeguards provided emergency first aid before medical teams arrived.
Authorities have launched investigations, but no animal has yet been captured or conclusively identified.
Was It a Shark?
Probably not. Although the injuries immediately prompted rumours of a shark attack, marine specialists say there is currently no evidence supporting that theory.
The bites occurred in shallow coastal water and involved relatively localized injuries to the calves rather than the large tearing wounds typically associated with shark encounters. Moreover, there have been no confirmed shark sightings linked to either incident. Instead, attention has focused on several fish species known to inhabit the Mediterranean.
The Leading Suspect: Triggerfish
One of the strongest candidates is the grey triggerfish (Balistes capriscus).
Although generally not considered dangerous, triggerfish possess exceptionally powerful jaws capable of crushing shellfish and sea urchins.
During their breeding season they become highly territorial and have been documented attacking divers and swimmers who unknowingly enter nesting areas.
Unlike predatory attacks, these encounters are usually defensive, with fish attempting to drive away what they perceive as a threat rather than hunting humans.
Marine biologists note that triggerfish attacks remain rare but are not unprecedented in the Mediterranean.
Could It Have Been a Barracuda?
Another possibility being investigated is the Mediterranean barracuda.
Barracudas are curious predators that occasionally approach swimmers. While bites are uncommon, they may strike if they mistake sudden movement, reflective jewellery or splashing for prey.
However, experts stress that confirmed barracuda attacks on bathers remain extremely unusual, and no evidence currently links the species to the Cilento incidents.
Why Are Fish Becoming More Aggressive?
Scientists caution against drawing conclusions from only two incidents, but several environmental factors could help explain unusual fish behaviour.
Warmer Sea Temperatures
The Mediterranean has experienced repeated marine heatwaves during recent summers.
Higher water temperatures increase fish metabolism, making many species more active and increasing feeding frequency. Warm conditions may also alter the distribution of species and extend breeding periods.
Similar incidents reported in Benidorm, Spain, in 2023 prompted researchers to investigate whether unusually warm coastal waters may have contributed to increased fish activity by accelerating their metabolism.
Scientists also noted that some of the fish involved had become accustomed to being fed by tourists, making them less wary of approaching people.
Breeding Season
For territorial species such as triggerfish, summer coincides with nesting.
Male fish aggressively defend eggs laid on the seabed and may charge at anything approaching the nest – including unsuspecting swimmers.
This behaviour has also been documented in freshwater species such as Europe’s wels catfish during spawning season, demonstrating that defensive attacks on humans can occur without any predatory intent.
Human Pressure
The combination of warmer seas, crowded beaches and increasing coastal tourism means encounters between people and marine wildlife are becoming more frequent.
Even if fish behaviour has not fundamentally changed, the growing overlap between swimmers and marine habitats naturally increases the likelihood of unusual incidents.
Should Tourists Be Concerned?
Experts say there is no indication that Mediterranean beaches have suddenly become dangerous.
Fish bites remain exceptionally rare considering the millions of people who swim in Italian waters every summer. Nevertheless, authorities advise swimmers to remain alert if unusual fish activity is observed.
Avoid disturbing schools of fish, refrain from feeding marine wildlife, and leave the water if fish begin circling or repeatedly approaching. Wearing reflective jewellery while swimming is also discouraged, as some predatory species may mistake flashes of light for prey.
The Bottom Line
For now, the mystery remains unsolved.
Investigators have not identified the species responsible, and there is currently no evidence pointing to sharks.
The most plausible explanations involve territorial triggerfish or another powerful coastal fish reacting defensively during the summer season.
As Mediterranean waters continue to warm, scientists expect interactions between humans and marine life to become more common-not because the sea is becoming more dangerous, but because environmental change is reshaping the behaviour and distribution of many marine species.
Sources:
- Unione Sarda – Alarm in the Cilento Sea: Swimmers Bloodied by Fish
- Italien.news – Fish Bite in Cilento: Swiss Tourist Injured in Pioppi
- Euronews – Benidorm tourists warned about fish attacks after 15 people a day injured by bites
- Scientific literature on territorial behaviour of triggerfish (Balistidae) and Mediterranean marine ecology.
