Now, populations of native species like the Gila and Apache trout have declined, and state wildlife officials are struggling to save them.

The Arizona Game and Fish Department started stocking rainbow and brown trout to promote an industry estimated to net the state nearly $831.5 million and the county $6.7 million.

Prof. Peter Reinthal, of the University of Arizona's Department of Ecology and Evolutionary Biology, said he's seen native populations drop over the years as exotic species have taken over.

"These trout have begun to hybridize, and the hybrids will always out-compete the natives, driving them away and essentially killing them off," he said.

Reinthal also said he believes that the Apache and Gila trout have been threatened because older brown and rainbow trout tend to eat the young of the Apache and Gila.

Apache trout are yellow-gold fish ranging from 6 to 24 inches and weighing anywhere from six ounces to six pounds. The Gila is a dark olive fish of about the same size.

The rainbow trout is olive to blue colored and ranges from 8 to 32 inches, and weighing more than 10 pounds in many cases. The brown trout is olive brown colored with yellowish sides weighing up to 22 pounds, according to the Arizona Game and Fish Department.

Julie Carter is the native trout coordinator for the Arizona Game and Fish Department. She has been working to create a balance in the populations while ensuring fishing opportunities remain intact.

"The Apache and Gila are in the process of being moved to streams around the state where they are surrounded by physical barriers that do not allow them to swim upstream, ensuring that they will not be bothered by stocked trout," she said.

Carter estimates that the ratio of stocked trout to native trout could be as much as 30 to 1. But just 30 years ago, native trout vastly outnumbered stocked trout.

The U.S. Fish and Wildlife Service has reclassified the Gila and Apache trout as "threatened." They were previously listed as "endangered." The U.S. Fish and Wildlife Service views an endangered species as "any species that is in danger of extinction throughout all or significant portion of its range" while threatened is considered to be "any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range."

"Decades ago, fisheries managers didn't fully realize the effects they would have by stocking nonnative fishes," said Prof. Scott Bonar of the University of Arizona's School of Natural Resources.

Carter believes that losing numbers of Apache and Gila trout will not severely affect the waters' ecology, but it has created new species of trout due to the hybridization between Rainbow trout and Apache trout. This has created new trout that have taken over many of the waters that were once ruled by Apache and Gila trout.

Todd Pringle works for the Arizona Game and Fish Department and he has seen these same effects through the development of trout fishing in Cochise County.

"The No. 1 most popular fish amongst fishermen in Cochise County is trout and that is what attracts people there," Pringle said. "While it has remained fairly steady over the past few decades as far as numbers are concerned, the number of non-native trout being caught continues to rise compared with the native trout."

Reinthal said the waters of Cochise County were once a important ecosystem for Apache and Gila, but the stocking of other trout has made them hard to find nowadays.

"Many of the lakes in Cochise County were once full of Apache and Gila fish, but through the restocking efforts, those numbers have declined just like anywhere else in the state," he said.

The biggest concern now is what the future looks like for the native trout because it is clear that stocking of trout will continue regardless of the effects.

"We have been trying to keep them contained in certain areas to try and ensure that we can keep them living in the state, so while they aren't found in areas that they once were, they can still be found around the state," Reinthal said.