Then he continued the verse: "That is no country for old men." I put an arm around the Professor and gave him a hug. He had taught me all I know about folklore. He was 70, and fishing and folklore had been his life's two passions. Otherwise, he was the sanest of men.

They tell a story that, as a young and dashing bachelor, he had proposed to the local schoolteacher—but on the morning of the wedding, the Mayfly was up, so off with him to the river with never a thought for the girl. Soon after, she married a man from another parish who had no interest in fishing and who took her to Paris on honeymoon. People say she was happy.

The Professor moved lightly away in his waders, on the balls of his feet, and I remained perched on a stone, my mind busy with pictures of a silver shoal of salmon making its way back from the Arctic Circle, guided by the earth's magnetic fields, by ocean currents, by the silent stars, coming nearer to the coast of Ireland, recognizing the home river by taste and smell. And there, in the cold clear waters of a mountain stream, they would lay and fertilize their eggs and the life cycle of the salmon would begin all over again.

This is one of nature's miracles, a vivid expression of the fight for life against near insurmountable odds. They say that out of every hundred or so eggs, four or five salmon survive their first year—and even then their struggle is only beginning. But the salmon is indomitable.

There is an old saying that God, who is a fisherman, bore his hobby in mind while creating Ireland, sprinkling the landscape with thousands of lakes and nearly ten thousand miles of fish-bearing streams and rivers, and arranging for the Gulf Stream to lap our long, serrated coastline—giving us a milder climate than our location would seem to warrant, and thus luring plenty of warm-water fish to the vicinity, just waiting there to be taken. Of all the bounty of Ireland's waterways, though, the salmon is the undisputed king.

In Irish folk belief, there is a mythical connection between the salmon and the life force, or soul. "Bradan Beatha," they say in Irish—"the Salmon of Life." Stories of the wisdom and magic of the salmon are legion, woven into the fabric of our lives. We present the image of this extraordinary fish to the world on one of our most attractive silver coins—and we credit the salmon with the power of healing, and with other gifts. We also remember the salmon's place in our history—and the myths and legends that attach to it.

As I watch a silvery body leap out of the river, high into the air, I am taken back 1,500 years. At the end of a long day preaching the Christian message, it is said, a tired and hungry St. Patrick came upon a group of fishermen, and begged them for a fish. The men promised him the next one they caught, and then the one after that—but each time they threw their catch into a basket instead, mocking that the fish were pagan like themselves, and thus not fit food for a holy man. Then a salmon, swimming upriver, jumped out of the water and landed in Patrick's arms. And the saint blessed the fish before tossing it back in the river with the words: "I give you a gift. Henceforth the salmon will leap higher than any other fish in the river." And so it does.

Salmon graced the table of the great pagan god, the Dagda at Killaloe, and the Irish never lost their taste for the fish. Salmon smoked over applewood was served in royal Tara's banqueting halls 2,000 years ago.

The early anchorites, austere religious men who disciplined their bodies, allowed themselves salmon or lobster as an occasional treat—with maybe a tincture of hazelnut mead on Christian feast days. (It is said, on the other hand, that they were wary of oysters on account of their supposed aphrodisiac qualities.)

Salmon was a favorite food of the legendary Deirdre of the Sorrows, Ireland's Helen of Troy. And salmon figures in the tale of another love-stricken Irish maiden, the Princess Grainne, betrothed to the aging chieftain Finn MacCool.

Grainne, they say, put the "come hither" on Dermot Ó Duibhne, glamour boy of the Fianna—the standing army of Ireland in early times. Fleeing with Grainne before Finn, Dermot left an unbroken crust of bread in each place the couple spent a night—a sign to Finn that he was still loyal to his chieftain. But when the two reached Killarney, in County Kerry, Dermot cast a rowan berry into the River Laune and caught a magnificent salmon. Grainne cooked the fish on a hazelwood spit over an applewood fire, and served it with fresh watercress and potent wine. The bread they left behind the next morning was broken. When Finn found it, he knew that they had become lovers.

The people of Kerry, who demand a good ending to a love story, adopted the salmon as their traditional dish. Up until recent times, it was served in all its glory on Christmas Day in the county, instead of the more mundane goose, turkey, or beef.

Finn MacCool figures again in another salmon tale, this one about the Salmon of Knowledge. For eons, men sought to catch this fabled fish. Finally, Fineigeas, the poet who was the tutor of the young Finn MacCool, succeeded. He carried the fish like a jewel in a basket made of osiers across the greensward and gave it to Finn to cook. "Touch not a morsel," he warned, "for whoever has the first taste will have all knowledge." Finn promised, and watched anxiously as the fish turned to gold over an applewood fire. Then a blister arose on the salmon's skin, and Finn pressed it down with his thumb. In so doing, he burned himself, and instinctively thrust his thumb into his mouth to ease the pain. That innocent action gave him the first taste of the fish, and with it the gift. Ever after that, when he wanted to look into the future, he sucked his thumb. (Most children are born curious and have an urge to do likewise, until they are told not to by their parents.)

In Ireland, we have a habit of stretching the truth. Maybe that's because we're an island people, living on the edge of what was once the known world, and thus perhaps not as accountable as some other people. Or it could be just that we like to tell strangers what they wish to hear. Whatever the reason, we boast about many things, maintaining, for instance, that the Blarney Stone will confer a honeyed tongue on those who kiss it, that O'Connell Street in Dublin is the widest street in Europe, that the River Shannon is longer than any other river—and that Lough Neagh is a lake vast beyond reckoning.

Indubitably it is large, about 153 square miles in area—but its chief claim to fame lies in the story of something odd that happened there long ago. If you are in luck, you may hear a fisherman singing the old ballad, somewhat in the manner of a Venetian gondolier: "On Lough Neagh's banks, the fisherman strays / On a cold clear eve declining / And sees the round tower of other days / In the waves beneath him shining."

That ghostly tower was part of the palace of the high king Eochaidh, which was submerged, with the nearby town, when Lough Neagh overflowed its banks. Li Bhan, the king's daughter, alone of all her family, survived the inundation—but she was fated to live in a grianan, a bower under the lake. When she saw the speckled salmon frolicking all around her, she longed to be one of them. "O Lord," she prayed, "make me a salmon that I may swim with the others through the clear green water."

Her prayer was answered: She was changed into a salmon, or, some say, a mermaid, and her lapdog became an otter, and the two lived happily underwater for 300 years. Then she allowed herself to be taken by a handsome fisherman. The pagan version of the story says that she married the fishermen and bore him three sons and three mermaids. The Christian version has it that she was baptized by the local abbot, and spirited to heaven by an angel. Which is the better ending, I leave to you.

Ireland's three most famous saints all relished fish and shellfish. Patrick was particularly partial to lobster, Brigid to oysters, and Columcille to salmon—that is, until the day he sat by the shore of Lough Finn in Donegal reading his office and a high-flying salmon, going by in a rush, drenched him and ruined his breviary. In high dudgeon, the saint declared that a salmon would never again be seen on the lake—and to this day it holds true, though the nearby River Finn is alive with the fish.

Columcille had bad luck with fish—or perhaps they did with him. On another day, while out on a boat, he saw a shoal of flounders passing by, and enquired, "Is this a removal?" "Yes it is, crooked legs," a pert young flounder shot back, falling around the sea laughing. Columcille was not amused. "If I have crooked legs," he answered, "may you have a crooked mouth!" And today, indeed, the flounder has a wry mouth, if you care to have a look.

Brigid's fondness for oysters figures in another ancient tale. A powerful druid, it seems, once gave his maidservant an exquisite pearl—then secretly stole it back and cast it into the sea. He then approached the girl and demanded either that she return the pearl to him or that she submit to his desires. The girl went to Brigid to plead for help. Just as she was speaking, Brigid's own servant came in bearing a plate of oysters for the saint's dinner. Inside the first one Brigid opened was the missing pearl. The girl returned the pearl, and Brigid arranged for her freedom, and for a dowry so that the girl could marry the handsome young herdsman on whom she had set her heart.

This is just a story, of course. What isn't a story is the enthusiasm of the Irish for eating all manner of creatures of the sea. That shellfish formed a part of the diet of medieval Ireland is proved by remains found in the Viking excavations on Dublin's High Street.

Somewhat later, visitors to our shores noted that the appreciation of ordinary folk exceeded that of the gentry for lobsters and crustaceans of every kind. In the 17th century, the secretary to Archbishop Rinucinni, Papal Nuncio to Ireland, sent back a report to his native Italy that "The fish of both river and sea are so exquisite and abundant that the common Irish eat freely of pike, hake, salmon, trout, [and] indeed all sorts of fish are to be had for astonishing value. We bought pilchards and oysters very cheaply indeed."

Indeed, fish and shellfish (above all, the latter) were so inexpensive in the Ireland of old that they were often considered the food of the poor, while the wealthy would prefer meat and fowl. Inns and taverns in the 18th century commonly posted notices reading something like "Here you can get straw for a penny, beer for twopence, and salmon or lobster for nothing." And in the famines and near-famines that bedeviled the country from the Elizabethan Wars in the 16th century to the Great Famine of 1845-47, oysters, periwinkles, limpets, cockles, and mussels saved many from starvation. (In times of plenty, fish was salted and hung up to dry as an insurance against lean times.)

Herring was another basic food of the poor. Jonathan Swift, Dean of St. Patrick's, immortalized the cries of the fishmongers of 18th-century Dublin in verse: "Be not sparing, / Leave off swearing, / Buy my herrings / Fresh from Malahide, / Better was never tried. / Come, eat 'em with pure fresh butter and mustard, / Their bellies are soft, and white as custard. / Come sixpence a dozen to get me some bread,/ Or like my own herrings, I too shall be dead."

In the Ireland of long ago, we boasted four great houses of hospitality where the traveler was made welcome for as long as he cared to stay. Today, guests to our shores are equally cherished, in smart urban hostelries, charming country inns, and grand rural manor house hotels alike. Many of these establishments—especially the rural estates—are known for their dining rooms as much as for their accommodations, with Irish fish and shellfish playing a featured role in the cuisine.

At Sheen Falls Lodge in Kenmare, County Kerry—a gracious country estate built in the early 17th century by Sir William Petty, the man who carried out the first census of Ireland—chef Fergus Moore graces slivers of lobster with a sea urchin rouille, fills lasagna with fresh local prawns, and smokes his own salmon. Sometimes he serves the salmon cold, thinly sliced, with herb-enhanced sour cream dressing; sometimes he pan-fries it and presents it with pickled chanterelles, or with potatoes pureed with truffle oil and saffron.

Dromoland Castle in County Clare is in the midst of prime fishing country, sitting on fish-filled Lake Dromoland, and with two teeming streams running through the estate. Local salmon is often prepared with cider butter sauce in chef Jean-Baptiste Molinari's kitchen—and there is a pronounced French flavor to such other house specialties as lobster fricassee with baby vegetables and panfried scallops with sauce vierge. (Much of the best cooking in Ireland today has Gallic accents—but the freshness and the authority of local ingredients gives the food vivid Irish character no matter what its inspiration.)

Longueville House in County Cork, a Georgian mansion built in 1720 and run as a hotel since 1969 by descendants of the original owners, benefits both from private fishing grounds on the Blackwater River, a few yards away, and from the best Atlantic seafood. Chef William O'Callaghan, the owners' son, smokes his own salmon or marinates it as gravlax; he also bakes it in puff pastry and adds basil and tomatoes. Sea trout is simply panfried and served with sorrel sauce, and cod might be baked in a crust of herbed bread crumbs and moistened with tomato sauce.

In the two dining rooms at the beautifully restored 13th-century Ashford Castle on Lough Corrib's northern shore, the seafood creations include filet of turbot with scallops in parsley dressing and poached lobster with truffle oil dressing. But chef Denis Lenihan proudly features salmon, too, with such dishes as river salmon with cabbage and cider vinegar, and smoked salmon with citrus fruits and coriander vinaigrette. Salmon has been fished on the Cong River and in the adjacent Lough Corrib since the days when the kings of Ireland made their home in the region. Here, as elsewhere in the country, the wise old salmon provides continuity, forming a living link between our past and our present.

I came again to the river, and saw the first of the salmon flash by to begin the life cycle again. But the scene was different this time. The trees were bare, and there was no well-loved figure in waders and fly-studded cap. The Professor had gone to join the heroes of old, and to fish legendary waters.