LAST SATURDAY, 500 to 600 pounds of the endangered rockfish were caught in the Washington stretch of the Potomac River, says Ray Fletcher, who, with his brother Joe, runs the city's main fishing center, Fletcher's Boat House.

Many of the anglers released the rockfish they caught, Ray Fletcher says, but some kept everything, taking home 15 to 20 rockfish, or striped bass, "the aquatic equivalent of the bald eagle," as outdoors columnist Michael Globetti of The Boston Herald describes it. The rockfish being caught in the Potomac are between 11/2 and 41/2 pounds, Fletcher says.

Washington is one of the few places in the country where there are no limits on rockfish. Maryland has a rockfish ban in its waters, including the stretch of the Potomac from Chain Bridge on up the river. There's also a rockfish ban until June 1 on the stretch of the river governed by the bistate Potomac River Fisheries Commission -- from the D.C. line near the Woodrow Wilson Bridge on downriver to the Chesapeake Bay.

Which leaves a loophole -- Washington. The District government is responsible for the Washington portion of the Potomac and it does not have a fisheries management program, meaning that you can catch and keep anything you want.

"The intended purpose of the (rockfish) ban is to allow the escapement of more fish" for spawning purposes, says A.C. Carpenter, executive secretary of the Potomac River Fisheries Commission. "Obviously, any taking of (rockfish) out of the water defeats the purpose of the ban."

On the other hand: "If they're catching that many fish, it must mean there's a lot . . . in the water and it makes you question the purpose of the ban," he says.

On the plus side, the rockfish being caught already have spawned, says Dan Ward of Fletcher's. "But don't take out bushels of them," he advises. "Keep just a few and put back the smaller fish so they grow up."

Unfortunately for the rockfish, the Washington stretch of the Potomac offers some of the best and most accessible fishing in the area, and anyone fishing there is bound to catch rockfish. The baits you use for other species in the river -- cut herring for catfish and bloodworms for perch -- are bread and butter for rockfish.

We fished off Fletcher's Boat House last Friday and caught three rockfish, one of them a nice three- pounder. We released all of them unharmed. The fishermen in the boat next to us were catching rockfish at a rate of about one every 10 or 15 minutes. And by the looks of their sunburns, they'd been at it for several hours. They kept everything. After a few hours, they held up a stringer to show off to a passing boat. It was full of rockfish -- 20 to 30 of them -- and all looked smaller than the ones we released. Our view is that that's grossly irresponsible.

Fletcher acknowledges that he's got mixed feelings about the rockfish. "We want people to catch fish and be happy," he says, "but not to catch so many (rockfish). We don't want them to be gluttonous."

Fletcher says he thinks that a self- imposed creel limit is a good idea, and we agree. He suggests two pounds as the starting point. "Don't keep anything under two pounds," he says. That's about a 16-inch-long rockfish.

Jack Buckley, a fisheries biologist with the District government who is working to establish a fisheries management program for the city, suggests a self-imposed creel limit of "three to five rockfish over 15 inches."

When the Potomac River Fisheries Commission's June 1 ban expires, the creel limit for the lower Potomac will be five rockfish per day over 14 inches and under 34 inches, Carpenter says.

There's no more endangered rockfish than the one at the end of your hook. If you catch one and want to release it, Buckley suggests the following: One, don't take it out of the water; two, be gentle. "The least amount of stress you give the fish the better," he says. The water in the river is warm now, and the warmer it is the greater the risk that stress or any kind of abrasion will harm the fish, Buckley says.

If the fish is bleeding or just plain exhausted when you land it, you may as well keep it.

There is one restriction on Washington Potomac fishermen. If you take a rockfish into Maryland, you risk a $500 fine and three months in jail -- even if you caught it legally in Washington. ELSEWHERE

If you're fishing for catfish, crappie, bluegill or sunfish, you're in luck. They seem seem to be biting all around. On the other hand, if you're looking for largemouth or smallmouth bass, be prepared to be patient. Many of the bass are still spawning and aren't feeding. Of those that have finished, the larger ones have turned wary again and will be much harder to catch until fall, according to Rob Guilford of the Rod Rack in Frederick.

"When the bass come off the beds in a couple of weeks, it will be nothing for some fishermen to catch 50 to 100 a day, but only two or three of those will be keepers (over 12 inches long)," Guilford says. "The really big bass got that way by being cautious about what they strike, and they don't lose that caution except during the spring and fall."

The big bluefish are still the prime target of anglers in the Bay, but the action has slowed down somewhat. Pat Raley of Sister's Store at Point Lookout, Md., says the fish are there but not as many as two weeks ago.

"The problem is that the alewives the bluefish feed on have dropped off," Raley says. "One of my suppliers only caught a few bushels today, and the other one didn't net any. If the baitfish come back in a few weeks, then the blues should, too."

Oceanside, the main catch is still flounder, with some spot and croakers being reported.