Somewhere over the Atlantic Coast a jet is winning its way to Florida with a precious cargo in the hold. It is a flounder, A very large flounder.

The flounder is salted and frozen on its wrapper is stamped the address of a taxidermist's shop. The taxidermist is going to mount the flounder and send it back north soon, where it will be tacked to the wall of Scheible's Fishing Center in Wynn, Md., with the notation:

Chesapeake Ray record; 11 pounds 12 ounces; caught by Angus Phillips, July 15, 1978.

That's right, folks. Today's message is being brought to you by the man who landed the biggest flounder every caught in the Chesapeake Bay.

Well, almost.

Cruel research discloses that while my catch will hold up to anything Marylanders have produced out of the bay, it is a distant also-ran to Virginia, who think nothing of 15-pounders.

But opportunities for immortality come few and far between for sinkerbouncers like me, and I'll take it.

The big flattie gobbled a handsome chunk of peeler crab off a bottom rig just south of Tangier Island on Saturday. We were drifting aboard Capt. Bruce Scheible's bay-built boat Sarah S., hoping to hook into some of the heavy sea trout that favor that area.

A couple of drifts over the 40 footdeep oyster shell botoom had surprised us with a few fice and six-pound flounder, which are not exactly common this far up the bay. Ther were nine of us aboard, and the trout were playing hard to get, so we kept at the flounder grounds.

I hadn't had a strike all day, and was busily trying to keep from falling asleep when something tried to yank my stout boat rod overboard.

"Rurrummmph," I snorted. "Whuzzat?"

It's a fish, dummy," one of my ill-tempered colleagues shot back. "Start reeling."

Which I did with sleepy precision until about halfway up, when the big fish decided he really didn't favor being towed around by a piece of dead peeler crab.

He gave a ferocious tug at the line, at which time I decided to pay a little more attention.

"Big trout," I shouted. "Get the net."

Scheible was over in a hurry, wielding a long-poled net that went three feet across. Just about them I hauled the fish to the surface and gasped. It looked like a mahogany tabletop.

"Good lord," said Scheible, and plunged the net under the fat flattie. The disgusted flounder chose at that point to end the brief affair. With one sweep of the tail it went airborne, snapped its mammoth jaws and broke the 30-pound-test leader in half.

And came down dead center in Scheible's net.

We dragged out Scheible's rusty scale and hoisted the fish on it. Twelve pounds. Later a brand new scale lowered the figure.

"Let open the champagne," said Carmine Fosco.

"Let's catch a bigger one," said Jack Vickery, which seemed a far better idea. The fish went the hold and everyone went back to work.

Except me. I spent the whole afternoon honing my filet knife and planning out the delightful task of removing every ounce of meat off that huge fish. NOthing makes a better meal than flounder.

Back at the door we rolled it to the cleaning table in a wheelbarrow. I was ready to cut, flicking th sharp edge of the knife with my thumb, when Scheible's brother Doug came thundering down the dock, shouting:

"Don't cut that fish. Don't cut that fish."

He was waving an orange sheet of paper when he arrived, huffing and puffing. With a shaking finger he pointed to the flounder line in the Maryland Sportfishing Tournament's Chesapeake Bay Division records.

"Flounder," it said. "Nine pounds 3 ounces, Charles W. Hutcheson, Camp Springs, Md., 9/8/77."

"It's a record," said Scheible. "And I just happen to be the representative for two taxidermy companies. You will want it mounted, of course."

"I'll mount it all right," I though. "On a dinner plate."

My hand went to the knife, Scheible was quicker. "All right," he said, "we'll fix it so won't cost you anything. I'll have it mounted and we'll display it in the restaurant. You can't eat that fish."

Scheible knows a Scotsman when he sees one. It was a deal.

I have visiting rights now, and Scheible said I can take the fish home on weekends whenever I want.