Photo by Terry Madewell.

When catfish guide Robbie Burr of Wadesboro fishes for blue catfish during the winter, he envisions darker shades of blue.

"Trophy blues that weigh 50 pounds or more take on a darker shade of blue that's almost jet black," said the former tournament bass fisherman, who sold his 85 bass-fishing outfits once he decided to fish for big catfish exclusively.

"I don't know if it's their age or their environment, but big blues definitely have a darker coloration than smaller blue catfish," he said. "I call them 'black catfish.' "

Trophy blues also have a different physique. They exhibit potbellies, while their smaller counterparts appear more muscular and streamlined.

Big blues and striped bass often share the same habitat. For that reason, Captain Gus Gustafson, a noted striped bass guide at Lake Norman (704/617-6812), joined a local catfishermen's club.

"In the winter, I'd catch big blue catfish while guiding for stripers because the two species favored the same places," Gustafson said. "I figured if I joined a catfish club and found out how those guys located big winter blues, I could learn more about striped bass movements, too."

Gustafson's catfish membership paid double dividends. He now guides for both species.

Like stripers, blues are big open-water fish constantly on the prowl for schooling baitfish and move about more than other catfish to dine. They prefer deep, well-oxygenated waters with gravel and hard sand bottoms. They also like clear waters with strong current, unlike channel cats and flatheads, which like turbid waters with only moderate current flow.

Only a handful of state waters satisfy the habitat preferences of blues, so housing for these fish is rather limited.

In the west, 32,500-acre Lake Norman has gained acclaim as a stronghold for big blues.

The N.C. Wildlife Resources Commission received more than a modest return from its 1966 stocking of 4,000 8-inch blue cats into the Duke Power Company lake, though it wasn't until the '90s that numbers of big blues started appearing in anglers' catches. The catfish angling has been on the upswing ever since.

Data from the N.C. Catfish Association Tournament Series (www. nccats.net) operated by Omar Edwards of Claremont and David Johnson's now defunct N.C. Catfish Championship Trail indicates that blues up to 55 pounds have been taken at Norman tournaments, along with numerous fish in the 30- and 40-pound class.

The former state-record blue of 85 pounds was taken from Norman on June 19, 2004, by 54-year-old Joel Lineberger of Long Island while fishing near his home.

With the influx of big blues, striped bass fishermen at Norman feared blue cats would compete with stripers for forage. However, a 2000-2002 study revealed that blue cats and stripers do not compete for shad and herring throughout the year: Blues consume mainly freshwater mussels during the warmer months and devour shad mostly after winter die-offs.

Though garnering less publicity, Norman's neighbor, 3,235-acre Mountain Island Lake, harbors big blues and serves as a regular stop on the NCCATS trail.

"Mountain Island is a very good lake for blue catfish," Edwards said. "Blues up to 40 pounds have been caught during our tournaments."

While blue cats have found a home out west, only incidental populations of blues reside near the densely populated cities of Raleigh, Durham and Chapel Hill -- the apexes of the Research Triangle.

Raleigh's famous trio of trophy bass lakes -- Jordan, Shearon Harris and Falls of the Neuse -- may yield big largemouth bass, but they're not noted for producing many fat cats as yet.