Beware bites if you swim with seals on St Stephen's Day

Hypothermia is not the only hazard facing Christmas Day swimmers at Sandycove's Forty Foot tomorrow. Those who dare to swim alone may risk engaging the attention of hyperactive, and quite hungry, seals.

The south Co Dublin bathing area, formerly colonised only by men, has become a haunt for the marine mammals. Up to 22 have been spotted together at one time, according to Mr Fred Espey, regular sea swimmer and Dún Laoghaire yachtsman. He says several incidents have occurred over the past year where bathers have been bitten.

Recently a woman had to have five stitches in her leg, and many women are now afraid to swim alone.

"They can be pretty fearsome creatures at the best of times, but the main problem is when they approach you and you pull your leg away suddenly," Mr Espey said.

Most are grey seals, known to be more aggressive than harbour or common seals.

"I have been swimming for 60 years, but in the last five years the number of seals in this area has risen quite markedly," Mr Espey said.

Those unfortunate enough to sustain a bite are advised to seek medical attention and may be prescribed a course of antibiotics. Ms Jane Gilleran of NUI Galway, who has been researching a virus which affected Ireland's harbour seal population last year, said that bacteria in seals' mouths could cause a condition known as "seal finger", which can prove serious if not treated.

Fortunately, grey seals are not so susceptible to the phocine distemper virus (PDV) which Ms Gilleran has been studying. Akin to distemper, PDV poses no danger to humans but can prove fatal to seals. Dogs which have not been vaccinated can also risk picking up the virus from dead carcasses on the seashore.

Figures gathered by Ms Gilleran and Dr Jimmy Dunne at NUI Galway indicate that some 161 dead seals were found on various parts of this coastline over the past 12 months.

"Given that some 22,500 seals died in Europe altogether, this is far less serious here than we had expected," Ms Gilleran said.

PDV was first detected in 1988 on an island in the Kattegat off Denmark, and spread rapidly. It is estimated that about half of Europe's seal population died in the epidemic, which spread to Northern Ireland. "As with 1988, the Baltic area was the worst affected this time, and it actually started again on the same island in the Kattegat," Ms Gilleran said.

The Irish Coast Guard has urged people not to swim alone tomorrow and to take basic safety precautions before setting out on water.