COOPER, Texas – A persistent south wind roiled the already murky waters of Cooper Lake. Sulphur Springs fishing guide Tony Parker wasn't concerned about the 20 mph wind, and he's learned to live with the lake's off-colored water.

Parker cut his outboard engine and drifted over a submerged hump in the middle of the choppy lake. His sonar lit up like an Etch-A-Sketch gone crazy, the squiggly lines sketching big schools of shad interspersed with bigger, hook-shaped marks that could only be game fish.

The guide heaved a long cast with his favorite lure, a four-inch chartreuse Sassy Shad rigged on a three-quarter-ounce lead head. He let the lure sink to the bottom, then started reeling it slowly but steadily back. Parker's rod heeled over and he was fast to the first fish of the day.

"It feels like an average Cooper Lake hybrid striped bass," Parker said. He was right. The fish was a chunky four-pounder with a fight so dogged it could have done well fighting out of its weight class.

Parker knows something about these fish. He and his clients have caught thousands of them since last summer and they've basically had the 19,000-acre lake to themselves. On the weekday that we fished, there were two other boats in sight, both of them operated by Parker's buddies.

When the fish stopped biting after about three hours, we'd put about 40 of them aboard, which Parker proclaimed to be an average day at Cooper. Two days before, he and a client had boated 80 hybrids. Parker's best day on the lake occurred last summer and produced 150 fish.

Parker is a fishing guide who learned his trade at Lake Tawakoni and Lake Fork. He's given up bass fishing at Fork but still fishes at Tawakoni, one of the fishiest lakes in northeast Texas.

"Tawakoni is a great fishing lake where you can catch striped bass mixed with hybrids and sand bass," said Parker. "Cooper is a sleeper that may be the best hybrid striper lake in Texas – at least for numbers of fish."

So why the lack of fishing pressure? Cooper is located about 90 miles east of downtown Dallas. The most direct route from Dallas is through Commerce. Cooper has a history of fluctuating water levels that's undoubtedly hurt its appeal as a fishing lake. During the 2006 drought, the lake level was 18 feet low and boat ramps were unusable.

Parker thinks local anglers have not figured out how to catch the hybrids, and visitors to the excellent Cooper Lake State Park may not know about the fish. Parker said most of the fishermen he sees in the open portion of the lake seem to be fishing for sand bass. They catch some big ones. The lake record for sandies is 3.22 pounds.

"I cut down on the number of sand bass that I catch by using a big lure," Parker said. "When the hybrids are chasing big gizzard shad, I like to use a five- or six-inch swim bait like a Storm WildEye Shiner. A big sand bass will eat the swim bait occasionally, but you won't catch many of them."

The biggest hybrid striper caught from Parker's boat at Cooper Lake weighed about 10 pounds. The official lake record is 11.22 pounds. Parker seldom catches a hybrid smaller than four pounds, which probably means excellent survival for fish stocked two years ago.

What: Hatchery-produced cross between white bass and striped bass. TP&W stocks 2 million to 2.5 million a year, divided among 24 lakes.

Fishing patterns: Hybrids are open water fish and usually relate to structure like a submerged hump or ridge.

Best season: Summer.

Bag and size limit: Five fish daily, 18-inch minimum size.

Tony Parker contact information: e-mail tawakonifishing@yahoo.com or call 903-348-1619.

Top hybrid striper lakes: Belton, Tawakoni, Ray Hubbard, Cooper, Graham and Miller's Creek.