As millions of Britons and other international travelers prepare for summer holidays, the Mediterranean Sea, a popular destination, presents potential hazards beneath its surface. Rising sea temperatures have altered the region's ecosystem, allowing species that thrive in warmer waters to expand their range and increasing the likelihood of encounters with potentially dangerous marine life and bacteria.
While experts emphasize that there is no reason to avoid swimming in the Mediterranean, awareness of these risks and knowing how to respond can help prevent incidents.
Marine Life Encounters
Sea Urchins: Commonly found clinging to rocks in shallow coastal waters, rock pools, and reefs, sea urchins, such as the purple and black varieties, can inflict painful injuries if stepped on or handled. Stings typically result in immediate pain, swelling, and puncture wounds. If spines break off under the skin, they can lead to infection, inflammation, and, in rare cases, damage to nerves, joints, or bone, potentially causing severe symptoms like muscle weakness or paralysis. Treatment involves prompt spine removal, soaking the area in hot, soapy water, and over-the-counter pain relief. Medical attention is advised for severe symptoms.
Jellyfish: The mauve stinger (Pelagia noctiluca) is noted as particularly troublesome. Its tentacles contain stinging cells that inject venom, causing burning pain, redness, swelling, itching, and blistering. While most recover within days, severe stings can lead to nausea, vomiting, headaches, muscle cramps, and breathing difficulties. Rinsing the sting with seawater and carefully removing tentacles are recommended. Medical advice should be sought for severe or persistent symptoms.
Lionfish: Originally from the Red Sea, lionfish have rapidly spread throughout the Mediterranean. These fish possess venomous spines that can deliver extremely painful stings, similar in effect to cobra venom, causing intense throbbing pain, redness, swelling, and numbness. While most stings are not life-threatening, severe complications like difficulty breathing and cardiovascular issues can occur, necessitating urgent medical attention.
Weever Fish: These small fish bury themselves in shallow, sandy coastal waters, with only their eyes and venomous spines exposed. Accidental stepping on them can result in immediate, burning pain that spreads through the limb, along with swelling, redness, and numbness. Nausea, dizziness, or fever can also occur. Serious complications are rare but can include infection or severe breathing difficulties. Immersing the affected area in hot water is recommended to break down the venom.
Scorpionfish: Masters of camouflage on rocky seabeds, scorpionfish carry venom in the spines along their dorsal fins. Stings cause severe pain and rapid swelling, potentially affecting an entire limb. More severe reactions can include difficulty breathing, fainting, and irregular heart rhythms. Immersing the affected area in hot water for 30 to 90 minutes is advised to alleviate pain, followed by thorough washing of the wound.
Bacterial Risks
Vibrio Bacteria: Thriving in warm, salty, or brackish waters, Vibrio bacteria pose a risk, particularly as sea temperatures rise. Infections can occur if the bacteria enter the body through open wounds. Consuming raw or undercooked shellfish contaminated with Vibrio can also cause illness, including diarrhea and vomiting. While most wound infections cause localized redness and swelling, the bacteria can spread to the bloodstream, leading to life-threatening sepsis. Avoiding seawater with open wounds, covering cuts, and seeking immediate medical attention for worsening symptoms are crucial.
Dr. Francis Hassard, a member of Applied Microbiology International's Clean Water Advisory Group, noted that the risk of Vibrio infection increases with warmer seas and during heatwaves. He advised that while the risk for healthy beachgoers is generally low, individuals with open wounds, recent tattoos, surgical wounds, or underlying health conditions like liver disease, diabetes, or weakened immune systems should exercise greater caution. Infections are typically treated with rest and hydration, with antibiotics used for more severe cases.