The youngster came racing up the dock at Champlin's Marina, breathless and wide-eyed.

"Mackerel," she gasped, "a whole school of them right off the dock. They're all over the place."

The announcement occasioned barely a murmur among the assembled yachties, who were clustered around hibachis at the foot of the pier grilling steaks and hamburgers as the sun glowed dusky orange.

Scores of weekend cruisers were tied at the dock. In the sterns of the gleaming Fiberglass power boats captains and their crews munched onion dip and canapes.

And in the middle of the glittering melange the speedy game fish boiled the water, snapping at bait fish 10 feet from the boats.

All but two of the yachtsmen were ignoring this incredible glimpse of nature in the raw.

In the back of a 50-foot Chris Craft one overweight skipper was struggling with a lure, trying to dope out how it would attach to his line. And on a 54-foot Hatteras another adventurer was casting an oversized silver spoon into the school of fish, holding the reel upside down and trying to snag a mackerel.

These are the seamen of the '70s, men and women who measure their ocean adventures in cocktail tumblers whose feel for the sea begins and ends at the throttle and the wheel.

It wasn't ever thus. Fifty years ago word of the arrival of voracious mackerel in the shallow waters of the Great Salt Pond would have spread like fire across the island. In those days Block Islanders made their living from the sea, and they saw a gift of nature for what it was.

But the hurricane of '38 wiped out the fish houses and they never were rebuilt. The fishermen drifted away and today Block Island stays alive on the money yachtsmen and summer people bring with them.

Most of the visitors get their kicks blasting around the sand-strewn roads on rental mopeds. A few are different.

Like Louis Feierabend, a scholarly Coloradan who has been coming here for many years to taste the fruits of the Atlantic.

Feierabend is a fisherman, the real thing, and for much of the year he contends himself with the wild trout streams of the West.

But in August he likes Block Island, where he can latch onto bluefish by whipping popping bugs off the rocks below the 250-foot Mohegian Bluffs. He landed an 11-pounder on a fly rod that way this year.

In the daytime Feierabend takes his aluminium skiff out in search of fluke and mackerel and more blues.

That's where he found me. I was puttering in after a day of fluke fishing when he came bearing up behind in the little skiff, waving his arms, and pulled alongside. "Did you see them?" he asked. "Mackerel in the pond? They're tearing up the sand eels right on top. I'm just going to get my fly rod."

"Need company?" I asked, and he nodded yes.

I tossed a lightweight spinning rod in the boat, he grabbed his fly and off we went.

A half-mile out in the shalldow tidal pond Feierabend spotted the quarry. It was slack low water and we could see bottom over the side; a circle of spume erupted 100 yards away as the mackerel took their meal.

He cut the motor and I grabbed the oars, gently piloting him into casting range. He worked the fly rod carefully, false-casting over the noisy school until his fly was past it, then dropping the streamer in the water and dripping line furiously so the fly came bobbing back through the fish.

"Got one," he said. The long rod bowed as the speedy fish began its flight.

Mackerel, kin to tuna, put on a show much like a bonefish, tearing off line in spurts, then resting, then tearing off again in buttom-hugging streaks.

Shortly Feierabend had the 1 1/2-pounder aboard, but the battle had spooked the others, so we sat and waited for the school to surface again.

In 10 minutes they did, boiling a circle of water again. We rowed into them and this time I cast a tiny spoon, felt the pickup and set the hook. The fish was bigger, a two-pounder, and had my heart pounding before it came to net.

We kept it up another half-hour, but our touch deserted us. Feierabend hooked two more but couldn't keep them on, and eventually the tide began to move and we called it quits.

We had enjoyed the fishing, but even more we'd enjoyed the waits between rises, when our eyes and ears were perked for the sound and sight of mackerel on the move.

"You know, we may have caught a dozen blues out there trolling today, but this was so much more satisfying," said Feierabend.

Indeed it was.