Pop quiz before you read this column: If you caught the biggest rockfish in the world, would you:

Eat it.

Mount it.

Let it go.

*

Aboard the Becky D, Ren Bowman grins with delight as his fishing rod throbs with the energy of a large rockfish.

"Uh oh. Could be moral dilemma time," he murmurs, straining as the striper zings the line off the reel in a final, powerful lunge for freedom.

I've heard many fishermen exclaim many things over the years when they set the hook into a really fine specimen -- but "moral dilemma" is a new one.

This is, after all, May, the month designated for Maryland's wildly popular "trophy" rockfish season.

Each of us aboard Captain Ed Darwin's charter boat out of Mill Creek near Annapolis is entitled to take home the biggest striped bass we can land (minimum legal size is 34 inches, about a 20-pounder).

It is the best shot Maryland anglers have at the largest stripers, females that spend most of their year migrating along the East Coast from North Carolina to Labrador.

Each spring the fish, which can live for decades and attain weights (rarely) of more than a hundred pounds, return to Chesapeake rivers where they were hatched, to spawn.

The trophy season is designed to let fishermen intercept the big cows after most have deposited their eggs and are headed back down the bay to resume their oceanic wanderings.

Darwin, a former teacher at Baltimore's Southern High, has chartered rockfish trips for 30 years. He did his part this day, putting us on a good school of fish near Bloody Point, the bay's deepest spot at 175 feet.

But keeper-sized rock, it seemed, had already moved south. We hooked and released a dozen of 2 feet or so in length. The biggest thrill was watching the seventh-grade daughter of Bowman's buddy, Chris Frederick, catch her first rockfish as dad videotaped it. (Frederick, of Ellicott City, is a businessman; Bowman, of Towson, a stockbroker.)

But now Bowman's fish, his "moral dilemma," was surfacing: no monster, but probably a keeper -- or would he return it? Darwin told mate Joe Spiegel to get out the big landing net, custom-built by the captain to boat especially large stripers with a minimum of stress.

A quick measurement -- an inch and a half shy of legal size -- took the decision away from Bowman. Darwin and Spiegel had the hook out and the fish back in the water, still vigorous, in under half a minute.

"Shouldn't even be a question," Bowman reflects. "We ought to be putting them all back." Darwin agrees. But, for most of us, it still is a big question.

Until recently, with rockfish, the main question was how long you wanted to keep catching them. Bowman, Frederick, Darwin, and yours truly: We all tell the same stories you hear over and over from those who have fished the bay for decades. There were few legal limits on how many you could catch, of rockfish and most other species. And we caught them, commercial fishers and sport fishers alike, as if there were no tomorrow.

But the day came -- Dec. 31, 1984 -- when there was no tomorrow. The state had slapped a moratorium on catching rockfish.

Scientists have since reckoned that the fish population was maybe a year away from total collapse. And now, just in the last few years the rock are back -- a fully-recovered species, federal fisheries experts announced Wednesday.

The new look of things includes lots of rockfish; also lots of new rules and regulations, quotas and limits governing our fishing for them.

And this more regulated environment is, it seems, good and necessary, and pretty much what's happening across a whole )) range of fisheries and other natural resources issues, as society tries to preserve environmental quality in the face of increasing population pressures.

But perhaps, just perhaps, something more exciting than regulation is also beginning to operate. I am talking about an environmental ethic; about saying: I am allowed to do this, but I won't. Regulations alone can prevent the worst, but we will never achieve the best without a well-developed ethical sense of our responsibility toward nature.

Which brings me back to Ren Bowman and Ed Darwin and Chris Frederick and an earlier trophy fishing day in May aboard the Becky D.

It was May 3, 1992. They were trolling, when something smacked unattended rod so hard, Bowman recalls, "it sounded like it had broken the holder." Bowman snatched the pole and jammed the rod into his friend's gut and said, "Fight it, Chris."

Frederick, a veteran big-game fisherman, but relatively new to bay rockfish, recalls, "I didn't even know how big was big, but when it finally surfaced -- "

Darwin breaks in: "You can't print in your paper what he said when it surfaced."

Bowman, who has been looking at and catching rockfish for 40 years, had never seen anything quite like it. Two years later, the only way he can describe it is to talk of his "feeling awed." I have talked to perhaps half a dozen people who have encountered giant, old rockfish, and "awe" is what they all say. Such fish seem almost a different race from younger, smaller specimens of their kind -- like the difference between a white oak seedling and the Wye Oak.

Stretched on Becky D's deck, the great fish measured an incredible 56 inches. Its weight was easily 75 pounds, and more likely 80 or above.

The state record rockfish at the time was a mere 55-pounder. The world record, the largest rock ever taken on hook and line, was a 78-pounder from New Jersey, 3 inches shorter than Frederick's catch.

Darwin had to decide fast. He looked at Bowman and Frederick. Did they really want to kill this fish? The great old rock, which had somehow survived the nets and hooks of some 30 years of unbridled fishing, had not spawned yet. Her belly was distended; about 8 million eggs, based on her body weight.

And, videotaping the fish for posterity, they threw her back. The biggest rockfish never caught.

Frederick concedes that he had moments of doubt later, but now he has no regrets. "Half the fun," he says, "is wondering how big it really was."

Bowman says, "I have never felt the least bit sorry. I can see a picture in the paper, us standing next to this magnificent fish, belly sticking out with 8 million eggs. It's not a picture I'd want."

In ironic counterpoint, a few days later a lawyer from Edgewater caught and kept a new state record rockfish, a 51-inch, 64.7 pounder, all perfectly legal. "My friends call me a shark, and today was just another big fish I fried," he told the press.

The point is not to propose the captain and crew on the Becky D for sainthood. But we do make choices, every day, that affect nature: to keep a big fish or not; to drive a less polluting car; to build on half an acre in town or five acres of forest; to fertilize the lawn or plant trees instead.

An "environmental ethic" sounds so grand, and daunting, but it is really an accumulation of lots of choices. If we don't make the right ones, we end up trying to compensate with rules. The proliferation of environmental regulation in recent decades is in part a commentary on the state of our environmental ethics.

Fishing is a fertile area for nurturing a new ethic. The rockfish's recovery promises to be just the first in a new era of management that could bring many species booming back. More rules will play a big part in this; but so can the increasing push from environmental and fishing interests for barbless hooks, catch-and-release and learning how to return fish without injury.

Ren Bowman plans another, very special trip with Ed Darwin later this summer -- to introduce an 8-year-old daughter to bay fishing for white perch. "I hope the resource will be there for her to enjoy what I have enjoyed," Bowman says. "The difference is she won't feel the need to take home a cooler full every time."