Alert for deadly seal virus heading our way

Another life: The first sun to sneak over the ridge lights up a small island out in the bay, gleaming on the weathered buttresses…

Another life: The first sun to sneak over the ridge lights up a small island out in the bay, gleaming on the weathered buttresses of rock that underpin its steep green slopes. Too difficult to live on and no longer worth grazing, Frehill remains a wild refuge safely distant from the shore, writes Michael Viney.

Ecologist David Cabot, landing there from a rubber dinghy a couple of Junes ago, found a score of common or harbour seals in a breeding colony with several pups. His news made me wonder how many distant seal heads have been Phoca vitulina rather than the grey seal, Halichoerus grypus, so much more familiar in the west.

A bit closer, of course, and the difference is plain: the common seal has the smaller, rounded head, with a tip-tilted nose and nostrils that meet in a V; the bigger grey has a sloping forehead, a Roman nose with parallel nostrils, and the look of a lugubrious Labrador.

Just now, it is the common seal that has the greater right to look forlorn, as a second outbreak of PDV, the often-fatal phocene distemper virus, begins to sweep around these islands. Most of the cases confirmed in the UK have been confined to the Wash area of England's North Sea coast, but it is only a matter of time before the early symptoms (respiratory distress, streaming nose) appear in seals along the Irish Sea coast.

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The first epidemic of PDV erupted in 1988 and killed more than 18,000 common seals in Europe. It was in Northern Ireland, as it happened, that scientists first identified the virus, related to measles and canine distemper (don't let your dog anywhere near). It was also the presence of the virus in dead porpoises and dolphins recovered from northern coasts that suggested the original path of infection between common seal populations. The annual migration of porpoises from the Baltic to the North Sea and English Channel coincided with the route of the PDV outbreak, as seems to have happened again this summer.

The seals' resistance to the virus has been weakened by organochlorine pollutants (PCBs) accumulating in their bodies. In the Wadden Sea, for example, at the outflow of the River Rhine, seal numbers fell in a year by 60 per cent, and some 7,000 dead seals have been found in that area so far in the current epidemic. A long-term Dutch study, which fed seals with herring from the heavily-polluted Baltic or the relatively clean Atlantic, has shown how organochlorines build up to impair the animals' immune systems.

No evidence was found during the 1988 outbreak to link the spread of the virus to water quality in the Irish Sea, and PCB levels in the Northern Ireland casualties were much lower than in mainland Europe. Even so, more than 200 Irish seals died.

Most of these were in or around Strangford Lough, Co Down, which still has the island's largest concentration of Phoca vitulina: perhaps 500 to 600. The summer's breeding season on the islands of the lough and the sands of Dundrum Bay will have added another 100 or so, bringing numbers to their peak.

Away from Strangford, the biggest resident group of common seals - about 200 - is in Glengarriff Harbour in Bantry Bay, where tourists are taken in small boats to watch them. From there to Donegal, perhaps 1,000 seals are clustered in sheltered bays and estuaries. In the last outbreak of the virus, only occasional deaths were recorded away from Strangford, and while grey seals can certainly catch the virus, they seem much more resistant to it.

Northern Ireland's responsibility for Strangford explains the prompt response of its Department of the Environment: it has set up a hotline (028-44615520) and it has enlisted voluntary organisations to help in a coastwatch for dead or sick seals.

In the Republic, the voluntary Irish Seal Sanctuary has invited reports (01-8354370/ e-mail: irishsealsanctuary@yahoo.com), although, apart from helping a few pups with mild symptoms, the prospects for rehabilitation are bleak.

The higher level of coastal awareness has had one very curious result.

The common seals of Frehill, with which I began, fish regularly in Killary Harbour, the long fiord running in between the mountains to Leenane and Aasleagh Falls. On September 11th, a "sick" seal lying on the mudflats beside Leenane was reported to the local Dúchas conservation rangers, Sue Callaghan and Ger O'Donnell.

Its furry flippers and thickly bristling whiskers were clearly not those of the common seal and eventually helped to identify it as Ireland's first recorded Arctic bearded seal, Erignathus barbatus. Born on floating pack-ice off Greenland in May, it had wandered to Killary, much emaciated, and utterly without protest as it was stretchered away into care.

Connemara can muster all manner of unexpected talents, and the seal, given the name Ookpik (Inuit for owl, to suit her rather owlish expression), is now being nursed back to fitness by Linda Wells, an experienced Canadian worker with seals.

Disdaining the crabs that bearded seals are meant to eat, the patient prefers mackerel and pollack - a bucketful of 20 fish, three times a day.

Extraordinary as its arrival may seem, it comes only three years after an Arctic walrus was photographed hauled out on a rock in Clew Bay, just around the corner. Further up the coast, snowy owls are beginning to hang around out of their winter season. Where does all this leave global warming?