As millions of Britons prepare to head abroad for their summer holidays, one destination will attract more visitors than almost any other: the Mediterranean.
Spanning more than 20 countries – including holiday favourites Spain, France, Italy and Greece – ‘the Med’ is famed for its sun–soaked coastlines and lifestyle that has inspired the world–renowned Mediterranean diet.
Around 18 to 20 million will make the voyage to the region – which encompasses Southern Europe, Western Asia, and Northern Africa – and many will likely take a dip in its crystal–clear waters.
But beneath the surface, the Med is home to a range of creatures and bacteria that, when encountered, can pose serious, and in some cases deadly, risks.
Rising sea temperatures have transformed parts of the region’s ecosystem in recent years, allowing some species that thrive in warmer areas to expand into locations where they were once rarely seen.
As a result, the chances of holidaymakers encountering some of these potentially dangerous species have increased.
Experts stress there is no reason to avoid swimming in the Med, but they say being aware of the risks – and knowing how to respond if something goes wrong – could help prevent a holiday from ending in disaster.
So, which creatures and bacteria should tourists watch out for, where are they most commonly found, and what should you do if you come into contact with them? Read on to find out.
Millions of Britons will travel to the Mediterranean for their summer holidays this year – but there could be hidden risks in the sea
The purple sea urchin is one of the most common species of sea urchin in the Mediterranean Sea
Sea urchins
You are never likely to be far from a sea urchin in the Mediterranean. As well as being common in the sea, some species are considered a delicacy and are served in restaurants across southern Europe.
The two species most commonly found in the sea are the edible purple sea urchin and the black sea urchin.
Small, round creatures covered in dozens of sharp, needle–like spines, sea urchins are typically found clinging to rocks in shallow coastal waters, rock pools and reefs. Though they are not aggressive, sea urchins can inflict painful injuries when stepped on or picked up by unsuspecting swimmers.
A sting usually causes immediate and intense pain, followed by swelling, redness and puncture wounds.
Spines from sea urchins can also snap off beneath the skin, where they can be difficult to remove. If left untreated, these can trigger infection, inflammation and, in some cases, damage to nearby nerves, joints or bone.
In some cases people can develop more serious symptoms, including muscle weakness, shock, paralysis and breathing difficulties, which require urgent medical attention.
These complications can lead to death.
Experts recommend removing spines as soon as possible, soaking the affected area in hot, soapy, water to help ease the pain, and treat with over–the–counter drugs like ibuprofen or antibiotics.
Medical advice must be sought, however, with severe symptoms such as muscle weakness, paralysis, aches and fatigue.
The Mediterranean is home to dozens of jellyfish species, but one of the most troublesome for holidaymakers is the mauve stinger
Jellyfish
The Mediterranean is home to dozens of jellyfish species, but one of the most troublesome for holidaymakers is the mauve stinger.
Officially named pelagia noctiluca, the striking pink and purple jellyfish may look harmless, but it can pack a serious punch.
Its long tentacles are covered in thousands of microscopic stinging cells that inject venom into the skin.
A sting typically causes an immediate burning pain, followed by redness, swelling, itching, blistering and visible, bumpy welts, also known as hives.
While most people recover within a few days, the pain can sometimes linger for weeks, and severe stings may leave scarring years down the line.
More serious reactions are uncommon but can include nausea, vomiting, headaches, muscle cramps and breathing difficulties.
Expert advice on treating jellyfish stings varies depending on the species involved, but one thing doctors agree on is that urinating on the sting is a myth and should be avoided.
Instead, anyone stung by a mauve stinger should leave the water immediately, rinse the affected area with seawater rather than fresh water, and carefully remove any visible tentacles without rubbing the skin.
Medical advice should be sought if symptoms are severe or fail to improve.
Originally from the Red Sea, lionfish only reached the Mediterranean around a decade ago but have spread rapidly ever since
Lionfish
Originally from the Red Sea, lionfish only reached the Mediterranean around a decade ago but have spread rapidly ever since, and are increasingly calling it their home.
Instantly recognisable, they have striking red, maroon and white zebra–like stripes, fan–shaped fins and 13 long, venomous spines along their backs.
Adults typically grow to between 12 and 18 inches long and are commonly found around rocky reefs, seagrass beds and shipwrecks.
While they are not aggressive towards humans, lionfish will defend themselves if disturbed or accidentally stepped on. Their venomous spines can deliver an extremely painful sting.
The venom consists of a toxin that is similar to cobra venom, and victims usually experience intense throbbing pain, along with redness, swelling, bruising and numbness around the wound.
Some people may also develop nausea, vomiting, headaches or dizziness.
Most stings are not life–threatening and can be treated successfully with prompt medical care.
But severe complications can occur, including difficulty breathing, fainting and, in very rare cases, cardiovascular problems, making urgent medical attention essential.
Despite their small size and unassuming appearance, weever fish are responsible for some of the most painful venomous stings in the Mediterranean
Weever fish
Despite their small size and unassuming appearance, weever fish are responsible for some of the most painful venomous stings in the Mediterranean.
The fish, which typically measure between four and eight inches long, spend much of their time buried beneath sand in shallow coastal waters, leaving only their eyes and venomous spines exposed.
As a result, unsuspecting swimmers often step on them by accident.
Although they are not aggressive, weever fish will sting if disturbed. Their sharp, venom-filled spines are said to be able to pierce through a leather boot, and can cause an immediate burning pain that quickly spreads through the affected limb.
Victims often experience swelling, redness and numbness around the wound, while some develop nausea, dizziness, headaches or fever.
The worst of the pain usually eases within a few hours, although symptoms can persist for up to 24 hours or, in some cases, several days.
Serious complications are rare but can include infection, tissue damage and severe breathing difficulties. This may require emergency medical treatment, and can lead to death.
Experts recommend immersing the affected area in hot water – as hot as can be safely tolerated – because heat helps break down the venom and relieve pain.
Anyone with worsening symptoms or signs of infection should seek urgent medical attention.
Scorpionfish are rarely seen because they can camoflauge perfectly into rocky seabeds and reefs
Scorpionfish
Scorpionfish are native to the Mediterranean and feature on many restaurant menus across the region. But despite being common, they are rarely seen because they are dubbed ‘masters of disguise’.
With their red and brown colouring, scorpionfish camouflage perfectly into rocky seabeds and reefs, making them extremely difficult to spot.
Although they are not aggressive, they carry a toxic venom in the spines along their dorsal fins – on the back – which they can use if stepped on or handled.
Stings cause severe pain, followed by swelling, which can take hold of an entire arm or leg within minutes of it happening.
In some cases, victims may also experience nausea, vomiting, dizziness, fever or muscle weakness.
More severe reactions can include difficulty breathing, fainting, low blood pressure, irregular heart rhythms and, in very rare cases, paralysis, making medical attention essential.
Experts advise anyone stung by a scorpionfish to leave the water immediately and immerse the affected area in hot water – as hot as can be safely tolerated – for 30 to 90 minutes, as heat helps break down the venom and relieve pain.
The wound should then be washed thoroughly with soap and clean water to reduce the risk of infection.
Despite their venomous spines, scorpionfish are safe to eat when properly prepared and cooked, and are considered a delicacy in many Mediterranean countries.
Experts have warned that rising sea temperatures are creating increasingly favourable conditions for vibrio bacteria to spread across parts of Europe
Vibrio bacteria
Unlike fish, Vibrio bacteria cannot be seen lurking beneath the waves.
The flesh-eating bacteria thrive in warm, salty or brackish water – when freshwater and seawater mix – and experts have warned that rising sea temperatures are creating increasingly favourable conditions for it to spread across parts of Europe.
Just this week, the European Centre for Disease Prevention and Control said the flesh-eating bug could become more common in holiday destinations including France.
Cases were also last month reported in Spain, linked to unusually warm coastal waters.
People can become infected by Vibrio – triggering an illness called vibriosis – if the bacteria enter the body through cuts, grazes or other open wounds while swimming.
Eating raw or undercooked shellfish – particularly oysters – contaminated with the bacteria can also cause illness such as diarrhoea and vomiting.
Most infections that enter through open wounds cause redness, swelling, pain and warmth around the affected area.
But in some cases the bacteria can rapidly spread into the bloodstream, leading to life-threatening sepsis.
Experts advise avoiding seawater if you have an open wound, covering any cuts with waterproof dressings and seeking urgent medical attention if redness, swelling or pain worsens, or if symptoms such as fever, chills or low blood pressure develop.
Dr Francis Hassard, a member of Applied Microbiology International’s Clean Water Advisory Group, said the risk of being infected by Vibrio bacteria rises when seas are warmer, during heatwaves, and in places where freshwater and seawater mix.
But, he told The Sun: ‘For most healthy beachgoers, the risk of serious illness is low.
‘The people who need to be most cautious are those with open cuts, ulcers, recent tattoos or surgical wounds, and those with liver disease, diabetes or weakened immune systems.’
Infections are typically treated through rest and hydration. Diarrhoea, one of the main symptoms of infection when the bacteria is ingested from food, can cause dehydration.
Other, more severe cases may require antibiotic treatment. Anyone with prolonged symptoms should seek medical advice.
