The other week I wrote on Morgan Runn, a catch-and-release, fly-fishing-only stream west of Baltimore. I was impressed that the stream held some good-size trout as difficult to catch as any I have fished over.

The day after the story was printed, I returned to Morgan Runn. On the bank beside a pool that had held three trout, ranging from 17 to 20 inches, was a nearly empty can of worms. Bait is illegal on catch-and-release streams, because fish take a beited hook deep where injury is usually fatal. None of the fish I had cast to earlier in the week was there.

It isn't the loss of those fish, taken illegally, that I regret as much as the loss of the experiences some of us might have had because of them. To explain, let me tell you about the fish that went to Harvard.

In southern Pennsylvania, near the village of Newvilla, is Big Spring Creek, one of the better trout streams in the East. The first time I fished it I spent an hour working a productive-looking riffle. I'd cast and cast, using various flies, but never got a rise. As I was just about to hang it up and head for home, a pickup screeched to a halt and a sour-looking, middle-aged fellow rolled down the window to ask how I was doing. I told him how frustrated I was, having just moved to Washington from New Hampshire, where I caught trout easiler, and now I couldn't catch a thing. The gentleman Extened, showed me three fish he'd taken elsewhere and I guess I sort of drooled, because he took pity on me.

"Want to see a nice trout?" he asked. "Leave your rod in the truck, and grab some bread from the loaf sitting on the front seat. It's illegal to carry a rod and bait at the same time on this stream." I did as he said. He tore off a small piece of bread, walked to the good-looking riffle where I could swear not a fish lay and tossed in the bread. I watched it bounce down the riffle until - fogrumph ! - it disappeared in a gigantic, explosive swirl.

I was dumbstruck. I'd worked that riffle for an hour and never gotten that fish to rise. "Do it again," I asked. He did, and again, fogrumph !, the bread disppeared in a whirlpool.

"I come here every so often and chum the fish with bread just to see where they lie," said my mentor. "That trout always sits there. You can throw everything you got in your fly box at him, and he won't rise. But float a little bread over him and he'll hit it everytime. He ain't no fool. He knows the game in this creek. He knows it's fishin' only. That trout went to Harvard."

We talked for a while and I proceeded to throw everything in my fly box at that trout. But he never rose. Frustrated, I quit and headed home.

The following weekend I was back at the riffle, this time with my own loaf of bread. I tossed a small piece in. It bounced down the riffle, and, fogrumph !, the trout was still there. With my hands shaking in anticipation. i assembled my rod and selected a muddler minnow from my flybox. Again, I worked that riffle to death but never got a single strike.

As the sun was setting and I was thing about moving back to New Hamsphire, another car pulled up. Down came the window and "Doing any good?" a young fellow asked. "Nope," I answered, "how about you?" "Nothing," I lamented, "I can't figure this dream out." I noticed the Virginia tags on his car, and we soon got to talking. He was having the same trouble learning how to cope with the difficult trout of Big Spring that I was, but since it was his first time on the creek and my second, I took pity on him.

"Want to see a good trout?" i asked. He did, I left my rod on the top of my car, grabbed some bread and led him to the top of the riffle. I tossed in a small piece, it bounced down the riffle where I'd been casting and - fogrumph ! - it disappeared in the usual splash. I looked at him and saw myself a week earlier. "Do it again," he asked. I did nad the trout again swirled.

"That trout went to Harvard," I said, pretending to know a lot myself. Then I explained how you could throw everything in your flybox at him, but he'd rise only to bread. While the Virginian looked on I told him about the sour-looking man who explores the stream with bread, and then I went back to throwing my muddler minnow at the fish. After many fruitless casts the Virginian got up, agreed that the trout would not be fooled, and at teh moment he was.

The rod jumped in my hand and for 29 minutes that fish battled my efforts to control him. Lying exhausted in my net, he was the handsomest rainbow I had ever caught, emerald green on the back and magenta along his sides. Legally, I could have kept him, since Big Spring, like most catch-and-release streams, allows keeping one fish above 20 inches. But I'd met two good people through that fish, and killing him seemed like an insult to that, let alone to Harvard. I gently worked him back and forth in the current to force oxygen-laden water through his gills. He regained his strength. I released him, and with a sudden flip of his tail, he splashed water on my glasses and vanished in the riffle.

That was my conversion to catch-and-release fishing. On crowded Eastern waters there is no other way to get trout and bass, our most overfished game fish, big enough and wise enough to challenge you to learn more about them. Fishing is biology more than luck. A good fisherman knows where fish will be, when they feed and what they'll be feeding on; but only good fish can teach you that. In the years since that trout, I have come through other fish to understand the biology of Big Spring, and to know that the biology of every lake and stream is its fingerprint. That's why I had hoped to fish again to those three large trout in Morgan Runn. I had hoped to learn.