Curt Bilbey has caught big fish before. Trophies. His catch last Saturday, however, surprised even him when the hook on a small hand-held scale collapsed under the weight of his Flaming Gorge Mackinaw.

When the fish was finally placed on the official post office scales in Manila, he found out just how big it was: 51 pounds, 8 ounces, 45 1/8 inches long with a girth of 31 3/4 Officially, it is the largest fish ever caught in Utah - by over 10 pounds - and the third largest lake trout ever hooked in the United States. Only Idaho, showing a 57-pound, 8-ounce lake trout caught at Priest Lake in 1971, and Michigan, showing a 53-pound lake trout caught in Lake Superior in 1944, have produced bigger Mackinaw. The world record is a 65-pound lake trout caught in Canada in 1970.Utah's old record was a fish - 41 pounds, 4 ounces - caught by Sonny Gonnuscio in 1985.

Bilbey, who lives in nearby Vernal, said he was fishing near the boat dock at Antelope Flats, within half a mile of where he'd hooked into a 34-pound Mack last year, around 5:30 p.m. when the fish hit. At the time he was trolling in about 94 feet of water and using a "Quckfish" lure attached to steel line.

"I could tell," he recounted, "the minute it hit it was the biggest fish I'd every hooked." He said it took him about 30 minutes to maneuver the fish close enough to the boat in order to use a gaff to boat it.

In lifting the fish out of the water the hook on the gaff started to bend. When the fish was landed, a nearby boater offered his hand-held scale to weigh it.

"I knew it was big, but not that big. My grandpa had caught a 39 3/4-pound Mack last week and this one looked shorter. When it straightened out the hook on the scales, though, I knew I'd better get it in to be weighed fast."

Bilbey said he has been fishing the Gorge for about 13 years. Three years ago he caught a 32-pound Mack, then last year the 34-pounder.

"I don't know if the fish are getting bigger or if I'm just starting to learn to fish the Gorge, but I know there's a bigger one out there. I know it and I'll be out there going for it. I just know there's a bigger one."