Last week, Maryland Gov. Harry Hughes took a day off to go bluefishing out of Solomons Island at the mouth of the Patuxent River. Within three hours, the fish box on the charter boat Kathy C was filled with 31 big blues.

"A year ago, we couldn't have done this," Capt. Bunky Conner said. "It's that simple. This time last year if you caught three or four fish it was a good day."

Charter and sport skippers are convinced a novel and stunningly effective commercial fishing operation in Virginia waters put the biggest crimp in their pleasure.

Last spring, a fleet of four 50-foot commercial fishing boats from Florida invaded the lower Chesapeake Bay. The owners had contracted with buyers in South America and the Mideast to provide hundreds of thousands of pounds of bluefish, and they intended to get them from the bay.

Using huge encircling nets 1,200 feet long and 40 feet deep, the boats surrounded schools of blues entering the bay from the Atlantic and hauled them aboard by the ton.

Virginia officials estimated that by the time the four boats had left the bay for ocean waters in mid-July, 760,000 pounds of bluefish had been netted. On a single July day, the boats brought in 92,000 pounds of blues.

Few sport fishermen believe it was coincidence that during this time they encountered a severe drop in their catch, from the lower bay north to Baltimore Light.

Hughes, responding to fishermen's complaints, urged Virginia Gov. Charles S. Robb to stop the assault on bluefish. On Aug. 2, Robb responded through emergency fishing regulations promulgated by the state Marine Resources Commission.

The commercial boats, which already had slipped out of the bay for better fishing in the ocean, never came back. Bay fishermen said they noticed a change for the better within a week.

"The fishing got better right away. Then it slowly built to a crescendo in September and October," said Bill Brener, captain of the sport fishing boat Chum King out of Point Lookout.

The emergency regulations, which outlawed net fishing by encirclement, were made permanent this spring, and the good fishing continues.

Jack Travelstead, head of fisheries planning for the state commission, said his agency studied two separate complaints.

The first was that the commercial operation could harm the overall Atlantic stocks of bluefish. "We think we proved that was impossible with just those four boats," he said.

The second complaint was that the operation could deplete local areas of blues, and sport and charter fishermen in Maryland and Virginia "pretty much convinced us that was true," Travelstead said.

He said the commercial techniques put "clearly too much pressure on the resource, particularly if the tactics were to proliferate." The technique was "at least as efficient as a trawl, and we don't allow trawlers in the bay."

This spring, fishermen are keeping busy--from the bridge tunnel at Norfolk to the Bay Bridge at Annapolis.

They may suffer later if the usual midsummer lull in bluefishing returns. When they got skunked last year, they could blame it on the commercial boats and did.

This year, they'll have to take the heat themselves.