Bottlenosed dolphins have made the Shannon estuary their main headquarters in Ireland. Lorna Siggins went in search of them

Several decades back, Susanne Magee wandered out to Kilcredaun Point near her home on the northern shores of Shannon estuary. At first she wasn't quite sure - but then she saw the gleaming arched backs breaking the surface, the flukes among the ripples. Several dolphins were playing not far offshore.

Consumed with excitement, she couldn't wait to tell an elderly neighbour. "Ah them!" the neighbour replied.

"Them's just say (sea) pigs. Sign of bad weather," he muttered as he shook his head and walked on.

Some 20 years later and Susanne and her husband, Geoff, still get teased about their "sea pig" passion; but it is one they can now make a living out of, as owners of DolphinWatch Carrigaholt, in Co Clare. The couple were pioneers when they began the business back in 1992, but their vessel is now one of several that takes visitors out to view the estuary's rich marine resource.

The 100 to 140 bottlenose dolphins living in the Shannon's mouth are the only known resident group of the species on this island. The area has been nominated as a Special Area of Conservation (SAC) under the EU Habitats Directive, and it has been studied intensively by the Shannon Dolphin and Wildlife Foundation.

The dolphins feed on shoals of sprat and mackerel and other fish swept into the river mouth by strong tidal currents, Geoff Magee tells us shortly after we have boarded the 15-metre Draíocht at Carrigaholt pier. The skipper takes a southerly course, crossing the main navigation channel in the wake of a large ship owned by Tyrrells of Arklow heading for Foynes.

Approaching the Kerry coast, Magee then heads east along a sandbank known as the Béal Bar. "Sometimes you can spot dolphins waiting for fish here on the tide," he explains. However, we are in the neap season, so chances are limited. We scan the horizon. Nothing to be seen, apart from a few guillemots taking their lunch.

The Draíocht alters course and heads west along the edge of the bar. Passing Kilcredaun Point to the north and Leck Point on the southern shore, the kids on deck count the waves in the light south-westerly, while the skipper and his crew - University College, Cork science students Damien Haberlin and Katy Egan - help to identify more guillemots, razorbills, and cormorants. Magee explains that the 14th-century ruin on Leck was a "peel tower" and was once linked to the mainland by a drawbridge, before the sea washed it away.

It's the sort of information that Magee disseminates at intervals from his bridge. Magee, from Wigan in Lancashire, but of Irish parentage, has spent his life at sea. "Fishing was the only straight job I ever had," he says, as he recalls how he first came to Dingle on the Irish coast, moved north to fish in Roundstone, Co Galway, and then spent three summers salmon- fishing in Alaska before returning to Co Clare.

Susanne is a New Yorker, but with a particular Irish pedigree. "Related to the O'Rahilly," says Magee, and he is about to elaborate when he spots a storm petrel to starboard. He relays this immediately to his passengers, some of whom seem to have forgotten that they are on a boat at all as they lunge wildly across the deck.

At this stage, there's a keen sense of anticipation, almost impatience. Nudging the Draíocht in close to Counihish, a cove about half a mile from Ballybunion Point, Magee drops speed. There's an excited silence, anxious heads scanning the waters - and then the first of several unmistakeable movements on the waterline.

The group of up to six dolphins may be part of a larger pod. Two juveniles, marked out by their paler shade of grey colouring, approach at speed and shoot under the stern, twisting and turning as they emerge under the bow. An acrobatic display continues for a good 10 minutes, as the pair leap out of the water, to gasps and shrieks of delight.

Bottlenose dolphins can reach up to 35 km an hour in short bursts. At one point, there's a slap of the sea surface with a fin - the sort of movement that the dolphins apply when herding shoals of fish into tight balls in shallow water before going for the kill.

It's been 90 minutes since we left Carrigaholt pier, but the skipper seems to be in no hurry. Magee takes the Draíocht in close to the sea stacks at Tonalassa, known as the Devil's Chair and the Devil's Footstool. Hundreds of fulmars nest in the stacks, made of layers of sedimentary rock which were once washed off the coast of Canada, we are told. The soft mudstone is riddled with caves which are often a haunt for grey seals.

The Draíocht heads for home, crossing the navigation channel once again as the 15th-century castle at Carrigaholt looms larger. "There are up to 40 dolphins beyond Ballybunion Bank, but conditions tend to get a bit fresher as you go further out," Magee explains. At the same time, dolphins have been known to swim up as far as Foynes, and there was a recent reported sighting only a few miles from Limerick.

He never guarantees that passengers will see the marine mammals, but his "encounter rate" is "almost 100 per cent" and customers have been more than satisfied throughout this past season. "People are sufficiently conscious of the environment now to know that there's always a chance that they won't want to approach us," he says. "Thankfully, we have moved beyond the stage where animals are expected to jump through hoops."

The Magees run up to four trips a day from Carrigaholt from April 1st until the end of October, subject to weather and demand. Trips last up to two hours, and they also run a sunset trip to Loop Head,Clare's most westerly point, to look at seabird colonies and watch out for minke and fin whales on their southward migration.

Carrigaholt is six miles south-west of Kilkee and signposting in Kilkee leaves a lot to be desired, but DolphinWatch has its own markers. The Cost for the two-hour trip is €18 for adults, €9 for children under 16 years of age, and warm clothes, rain gear and sensible shoes are advisable. Booking is imperative, given the demand and the weather constraints, and Susanne Magee takes calls from 8a.m. to 6 p.m. at 065 9058156. Email: info@dolphinwatch.ie Website: www.dolphinwatch.ie