Shark spotting in the summer

This fine but humid summer, wreathed in evening sea mists, has produced some delectable sunsets over the Atlantic, so different from the rich, stormy spectacles of autumn, and filling a different quadrant of the sky. The islands darken under a backdrop of floral pinks and golds, and, as the light fades, the sea grows a silky skin of mauve, a colour only nature knows how to use with any taste.

Such tranquil weather brings fish by night to forage far up into the shallows, among them the soft-boned rays and dogfish. And rarely, perhaps, a far bigger elasmobranch relation appears among the scavengers. If the odd blue shark, Prionace glauca, pokes its long nose into waist-deep water off Maine, I don't see why it shouldn't in Co Mayo.

That would only be a cause for wonder, however: we're not talking Jaws here. This graceful, slender shark, its back a vivid cobalt blue, is mainly an oceanic nomad: a fish hooked and tagged off Connemara may be caught again off New York. It is typically an offshore, deepwater species, cruising slowly at the surface with its fin showing, or gliding down after squid.

But summer warmth and food brings the smaller blues of the north-east Atlantic (up to 2.5 metres) closer inshore, to feed on shoaling sprats and mackerel and to hunt around reefs and wrecks. They come well within range of sport-angling charter craft with deck-space for a dozen sturdy shark-rods. More than 40 such charter boats are operating now off the south and west coasts, and shark-fishing is probably the fastest-growing sector of Irish deep-sea angling.

Until quite recently, this might have been depressing news for those concerned with elasmobranch conservation. Sharks grow slowly, take many years to reach maturity, and have a very low replacement rate. Their populations across the world are under severe pressure from unregulated commercial fishing, and hundreds of thousands of blue shark are killed as a "by-catch" each year by fishermen trawling for squid.

Compared with that, the threat from game angling seems trifling and purely local. In these islands, it has focused on the coasts of south-west England, where, in past decades, blue sharks were hung on harbour gibbets for trophy photographs. They were part of the wider western horror-thrill that needed sharks to be aggressive, man-eating monsters.

Attitudes are different now. Interest in sharks has grown to the point where scores of thousands of people pay to go shark-diving with a camera in the warmer corners of the world. In Irish sea-angling, too, photographs now tell a different story: no longer corpses hung up by the tail, but live sharks, tagged after catching, and about to be released into the waves.

You can be impressed by this at the charter website (http://homepage.tinet.ie/ bluewater) of John Brittain, senior helmsman of the Clifden lifeboat and skipper of the 42-foot Blue Water, which tagged 137 blue sharks in 1997 (no one talks about the "summer" of '98).

The season peaks from mid-July to early September, when anglers with pounding hearts can hope for two or three blues at once circling the boat and its dangling baits of mackerel. The sharks are not exactly giants, averaging about 27 kilos with some over the specimen weight of 45 kilos, but there is always John Brittain's personal best of 70 kilos to hope for.

He does the measuring and tagging as part of the research programme run by the Central Fisheries Board and so also has the support of the Shark Angling Club of Ireland (http://homepage.tinet.ie/ sharkclubireland/). Formed only last year, the club insists on a catch-and-release policy. In its first international tournament, organised for Downings in Donegal next month, "The one rule here is no shark on the pier".

But the virtue of releasing the blues is often soured by knowing that their chances of a full lifespan are slim. Many of the tags clipped on aboard John Brittain's Blue Water are recovered from the Azores, where Spanish long-line fishermen have made huge inroads into the shark population.

Most of the blues caught around Ireland are immature females, which make them especially important to conservation. Most of the blues caught off New England, on the other hand, are male - a sexual segregation which biologists are still studying, among them an elasmobranch group in Trinity College, Dublin.

The blue may be the commonest shark around Ireland and almost the only one caught by anglers; it is not, of course, the only species in our waters. As shark angling becomes more specialised, the much tougher, more powerful porbeagle may become a cult target, as it is already in Britain. The world record for this shark is 230 kilos, for a fish caught off Dunnet Head in Scotland.

Lamnanasus is talked of as "shy", which is to say that it rises from the deep to the scent of the chum-trail and mackerel baits hanging from party balloons, and the scream of the reel is the first the angler knows about it. After the long battle, the fish is sometimes let go by cutting the trace, so that some porbeagles are swimming around with several hooks in their mouths, having escaped both from long-lines and charter-boat anglers.

This is another ocean-going shark, mostly found far down in deep midwaters. There are, by one knowledgeable account, "large concentrations" off the west of Ireland which begin to migrate inshore in June, with peak numbers around the coast in autumn. Very large ones, of almost three metres, have been caught within a kilometre of beaches in Devon and Cornwall.

At its biggest, the porbeagle, with the closely similar mako shark, has sometimes been mistaken for the notorious great white shark, villain of Jaws.

Last month, a great white "of 15 to 20 feet" was reported to have entered Scotland's Scrabster Harbour, close to Dunnet Head. In Ireland, there have been grapevine rumours of a sighting in Belfast Lough. But this remains unlikely, and there has been no authenticated record of a great white in Europe north of the Bay of Biscay.

Porbeagles are fish-eaters and have never been implicated in an attack on humans. They are, however, inquisitive and have been known to approach and investigate divers at salmon farms in the Shetland Isles and to harass seals nearby. This, promises the European Elasmobranch Association, "is considered to be territorial behaviour rather than an attempt at a meal". If a diver takes time to look, a porbeagle has a very characteristic white flash on the lower trailing edge of its first dorsal fin.

Email address for the EEA: sharks@naturebureau.co.uk