ASHLAND — Like 9 year olds are want to do, Ben Freeman launches a worm with a short but demonstrative cast between two willow poking through Emigrant Lake's surface.

ASHLAND — Like 9 year olds are want to do, Ben Freeman launches a worm with a short but demonstrative cast between two willow poking through Emigrant Lake's surface.

As the worm sinks slowly, Ben waits impatiently for the jerk he expects from the unexpected.

Will it be yellow perch No. 12 of the hour? Perhaps another fat crappie, a ready-to-spawn bluegill or another one of the two bass here?

The expected jerk soon follows. But this time, it's accompanied by a horrendous yank that taxes the drag on his closed-face reel.

"Holy crud," Ben barks. "I don't know what it is, but it feels huge."

Moments later, with the aid of one friend, his younger sister and his father, Ben summarily hauls his catch over the boat gunnel.

A 3-pound channel catfish dangles with the hook imbedded beneath its whiskers.

Now, it's warmwater fish biologists thinking a "Holy crud" of their own.

Ben's catch Sunday along the southern end of Emigrant Lake is proof that something unnatural, or illegal, is underfoot at this popular angling reservoir southeast of Ashland.

"Finding a smaller fish like this suggests that someone is illegally introducing channel catfish to that lake," says Gary Galovich, the western Oregon warmwater fish biologist for the Oregon Department of Fish and Wildlife. "We definitely don't want channel catfish stocked out there."

The ODFW has a long-standing policy that they remain the sole decider on which fish get stocked in what public water bodies for many reasons — chief of which is a need to protect native or desired species from invaders' harm.

As a non-native predator, channel cats have the potential to alter the balance of the lake's current species, which already have been over-run by illegally introduced yellow perch.

Another potential long-term concern is for channel cats to somehow slip out of Emigrant Lake and find their way into the Bear Creek and upper Rogue River basins, where over generations they could out-muscle native salmon and steelhead juveniles — the backbone of the Rogue basin's storied fisheries.

"This is something we definitely need to watch," says Dan VanDyke, the ODFW's Rogue District fish biologist. "Just looking at the dietary needs of channel catfish, they certainly match the dietary needs of (salmon and steelhead)."

Channel cat's dietary needs here actually would include young salmon and steelhead.

"Certainly, they'll eat fish," VanDyke says.

There's also the possibility that Ben's channel cat isn't an Emigrant Lake immigrant after all.

Two channel cats over 26 pounds were caught there in the '90s, and only one small fish was found there in 1996, suggesting that someone dumped the initial cats there in the early '90s.

Whoever did so presumably hopes the fish would breed and establish themselves as a regular fishery there.

Ben's channel cat is the first confirmed of its kind there in nine years. Could it be proof that at least a few channel cats are reproducing there?

"The whole idea of natural production is a really big 'if,'" Galovich says. "But there's always that potential.

"Either way, we definitely don't want to have channel catfish out there," Galovich says.

Clearly, these three young Medford worm-drowners didn't expect their Sunday afternoon at Emigrant Lake would turn into a fishy whodunit.

Ben, his 7-year-old sister Maggie and 10-year-old friend Nick Solomon instead are happy busying themselves with heavy doses of perch, crappie and bluegill. Nothing special, but better than video games.

The last bite of the day turns into the pisces-de-resistance.

As his rod doubles over, Ben's "Holy crud" gives way to the sort of merry chaos common when kids go fishing.

As Ben pulls and reels, his father clumsily tries to strengthen the drag. Maggie stands poised with the fish mallet ready to turn the cat's eyes into X's.

The fish is on the surface, but some adult forgot the net. So Ben hands his rod to Nick, then reaches down and pulls the catfish skyward by the leader.

"Dude," Maggie says. "If it was me and that fish was a little bit bigger, it could have pulled me into the water."

After some quick photographic evidence, the catfish is returned to the lake.

Perhaps that's not the best choice, but it's easier than showing your kids that some animals should die simply for being there.

What remains is a picture well worth these 773 words, a lesson on the dichotomy of illegally introduced fish species.

They may be fun to catch now, but what does their presence mean later?

"Whatever," Ben replies. "Just make sure you tell everybody that I was the one who caught it."

Reach reporter Mark Freeman at 776-4470, or e-mail