Larry Laskin stood on a bank of the Potomac River, staring down at two nagging problems. The most immediate was how to unsnag his fishing line from the bottom of the river without snapping his cane pole. A more serious dilemma was how to accomplish it before his friends returned to tease him.

"Larry, it looks like you've got something there," said Lorena Sibrian, as the 22-year-old Laskin tugged mightily on his pole. "It must be a rockfish."

On another day, the slings and arrows of his nonfishing friends might have stung young Laskin. But this afternoon was too sweet with the smell of honeysuckle and bright with light to be ruined by anything short of a tidal wave.

In case you didn't notice, last Sunday actually lived up to its name. After what seemed like four score of drab weekends, after enough spring rain had fallen to upset the Good Humor man, we finally got half a weekend worthy of an afternoon traffic jam.

On Sunday there was not an empty picnic table within 50 miles of Washington. You couldn't have squeezed another body into East Potomac Park with a sledge hammer. Great Falls Park in Virginia had barricades up by midday to keep out any more traffic.

Even at River Bend Park, which sits on the Virginia shore of the Potomac, two miles above Great Falls and consequently two miles from the river's greatest attraction, there were so many people recreating that Margaret Bunger blamed them for scaring away her fish.

"I think it is too noisy here for fishing," said the Dutch woman, holding an eight-foot cane pole in one hand, and a surf fishing rod capable of landing a tugboat in the other. Her two sons, Nils, 7, and Frank, 4, were rolling in the grass with two puppies they discovered at a nearby picnic. "We would have come here anyway."

Bunger's fishing luck was not shared by John Strother, a 54-year-old Arlington sanitation worker. On Saturday and Sunday, Strother caught 31 pounds 7 ounces of catfish and bluegills to win an annual spring fishing contest sponsored by the Fairfax County Park Authority and Eddie Bauer Inc.

The contest was an old-time event held simultaneously at River Bend, Lake Accotink and Burke Lake, all in Fairfax County. Prizes of fishing tackle were awarded at each location for such categories as the largest catfish, most fish caught, the oldest fisherman and youngest fisherman. More than 100 people paid a $1.50 fee to enter and it seemed like half of them won something.

Had there been a category for tales that stretched credulity, Ron Walker, Bob Callahan and Ed Robinson would have easily won. Walker and Callahan, both Fairfax County policemen and Robinson, a coin dealer from Sterling, spent nine hours fishing from a rowboat rented at River Bend Sunday. They returned to shore with 107 fish weighing 22 pounds and a story of a rabid black snake.

"It swam up to the boat and tried to get in over the oarlock," said Walker, a fair skinned type who had turned bright red hours before.

"It about scared me to death. We had to hit it with an oar," added Robinson.

"Then it swam to an island and climbed a tree," concluded Callahan.

With the exception of that story, the tournament suffered a lack of trophy-sized specimens. At Lake Accotink, for example, the winning catfish weighed just seven ounces, and the oldest fishermen was a youthful 47. There were no crappie caught at River Bend and no muskie pulled from Burke.

"We were a little disappointed this year with the number of fish pulled out and the size of them," said Doug Robinson, the manager at Burke Lake.

If anyone else was disappointed, they did not express it. At River Bend people were too busy picnicking, getting sunburned or hiking trails bordered by honeysuckle, dames rocket, wild hydrangia and valerian and shaded by paw paw trees, which in the fall bear fruit that resembles a cross between a banana and a pear.

A few yards from one such trail, Roger Dupre and his two sons fished their favorite eddy of the Potomac, just below a fast moving and sweet sounding rapid.

"I've fallen asleep here more than a few times," said Dupre, an Air Force officer stationed at the Pentagon.

While Dupre sat on the shore, his two sons stood on either side of a tree and willed fish to bite. Eleven year old Joseph had already landed a two pound catfish, while 13-year-old Michael had caught one half that size.

"I've been skunked," said their father, who looked a few blinks away from another riverside snooze.