Proud fishermen who believe they’re bringing home a monster brook trout for their summer fish feed might want to look twice. Chances are, that great catch is actually a laboratory-created breed of hybrid supertrout called splake.

Most anglers are happy to let that tidbit swim in one ear and out the other, however.

“They hear trout, and that’s all they care about,” said Gene Thompson, owner of a sporting camp on Frost Pond near Ripogenus Dam. “Usually, they come to camp to catch a fish, and they’re catching big fish.”

For the past decade, the Maine Department of Inland Fisheries and Wildlife has been stocking splake in an increasing number of lakes and ponds. Last year, 90,000 splake were stocked in 53 waters scattered from Aroostook to Kennebec County.

This fall, the department will consider a management plan that calls for continuation of the splake- stocking program, which biologists have called highly successful.

The fish is heartier, larger and some say easier to catch than its wild relatives.

The first splake was born in a Pennsylvania laboratory in the 1870s, when biologists combined the genes and the names of spotted and lake trout. Fertilizing eggs from a lake trout, also known as togue, with milt (fish sperm) from a spotted trout, also known as brook trout, results in a hybrid that exhibits the most desirable characteristics of both species, said Tim Obrey, a fisheries biologist with DIF&W.

It’s a designer fish, created for anglers, and has been stocked worldwide since the 1950s.

Pink splake flesh has a texture and flavor similar to brook trout, but the fish grow more quickly and reach larger sizes that are more typical of togue.

A 4-year-old brook trout averages 15.4 inches in length, while a splake of the same age would typically reach 19.4 inches. The world-record splake weighed more than 20 pounds.

The coloring varies, but many splake sport the brightly colored spots that make brook trout a desirable trophy fish. The major physical differences between similarly sized brook trout and splake lie in the internal organs, although a splake’s tail is typically more forked than its square-tailed father.

“It’s really tough to tell the difference unless you’ve got them side by side,” Obrey said. “People misidentify it all the time.”

It’s not unheard of to catch brook trout and togue in the same pond, but in the wild the two species have never been known to produce a splake. The trout species are genetically similar, and hybridization in fish hatcheries has been tremendously successful for 130 years.

So why don’t they breed in the wild?

Scientists believe it’s a simple matter of preference. Each spring, brook trout head to shallow streams for spawning, while togue cluster in rocky shoals along lake shores, and no cross-fertilization occurs.

The bigger mystery lies in splake themselves. The females produce eggs, and the males produce milt, but a second-generation splake has never been found in the wild. Hatcheries have successfully manipulated breeding to create such a fish, but splake released into the wild don’t seem inclined to get down to business, Obrey said.

If a wild splake were ever found, fisheries journals would be clamoring to publish the proof, he said.

This biological quirk has led to the major criticism of the splake program. Anglers question why the state is spending tax dollars on a type of fish that cannot reproduce.

“People don’t understand the philosophy behind stocking in general,” Obrey said. “Less than 5 percent of all the fish we stock are ever intended to reproduce.”

Most stocked fish of any species are caught within a few months, he said.

“That’s what we’re supposed to do. We create fishing opportunity,” Obrey said.

But some fishermen argue that DIF&W is using splake to replace native brook trout, taking away the opportunity for anglers who prefer what they fondly call brookies.

“Some of the people who have been coming for a long time don’t want anything to do with them [splake],” said Thompson of Frost Pond anglers. “They’re adamant that they taste different.”

In a competitive situation, the larger, stronger splake would squeeze out local brook trout.

That’s why splake are only stocked in ponds where efforts to maintain brook trout populations have failed due to habitat problems, Obrey said.

In many Maine ponds, introduced species such as bass and perch prey on native brook trout, destroying the fishery. But splake grow fast enough to compete with the warm-water fish, sometimes even preying on the predator species, he said.

But the splake’s major job is to satisfy a group of anglers who have demanded more opportunity to catch large trout. With fish that are triple the size of brookies, splake are doing that job well.

Different fish simply fit different needs, Obrey said, pointing to a list of the five game species that are stocked in Maine waters. Splake make up only 7.5 percent of the fish stocked by DIF&W, and Obrey recommends that number remain steady for the foreseeable future.

The other stocked fish are landlocked salmon and four varieties of trout.

“Our job is to create fishing all over the state, and these are our tools,” he said.