Producing and stocking rainbow trout for anglers is the single most expensive license funded fishery program managed by Idaho Fish and Game. The majority of funding to operate the trout stocking program comes from the sale of fishing licenses. During the last ten years, the funding available for the trout hatchery program has been relatively stable, but the cost of fish food has increased by more than 150 percent. In 2011, managers were forced to reduce production of catchable-sized trout by 18 percent to keep the program within budget. Since that time, the department has taken additional actions to cut costs and increase efficiency in the hatchery trout program. The department closed a small, inefficient hatchery and trout production was shifted from less efficient hatcheries where fish disease and water issues resulted in less efficient production, to hatcheries where more fish can be produced using less fish food. By focusing on efficiency, Fish and Game has been able to maintain the 2011 levels of trout stocking despite continued rising costs.
The sole purpose of the department's catchable trout stocking program is to provide recreational fishing. The number of fish stocked is important, but the real measure of success is how many of the fish stocked are actually caught by anglers. In 2011 Fish and Game launched a major evaluation to better measure the success of its hatchery trout stocking program. The "Tag-You're-It" evaluation spanned four years and relied on anglers returning or reporting tags from trout they caught as the basis for the evaluation. During that time more than 130,000 hatchery trout from the state's three largest trout producing hatcheries were measured, tagged and stocked into 117 different Idaho waters. Anglers across the state were asked to return or report tags from fish they caught. Rewards were offered for some of those tags, and thousands of anglers assisted by returning or reporting tags. A study of this magnitude using traditional, labor intensive methods of creel survey and check stations would cost millions of dollars and be cost-prohibitive at a time when money and budgets are tight, but with the help of anglers, the Tag-You're-It evaluation was very cost effective and provided conclusive scientific results.
The most striking results in this statewide study came from Idaho's larger lakes and reservoirs that are most dependent on hatchery stocking to provide the bulk of the trout fishing. The "Tag-You're-It" evaluation clearly showed that 12-inch rainbow trout were caught by anglers at a much higher rate than 10-inch rainbow trout. Across the entire study, less than 1 of the standard 10-inch rainbows was caught for every three stocked, but anglers caught more than one 12-inch trout for every two that were stocked.
A 12 inch rainbow trout weighs about 70% more than a 10 inch trout. It takes more feed to grow them bigger, so each one costs more to produce.
"We don't have more money to buy more fish food, so the shift to larger trout will mean that fewer trout can be produced and stocked," said Fish Production Manager Gary Byrne.
"Our four year evaluation shows that in places where we switch to stocking larger trout, less means more," saidState Fishery Manager Jeff Dillon. "The waters that will be stocked with 12 inch trout will receive stocking numbers reduced by about 40% but since larger trout are caught at almost twice the rate, the number of trout that anglers catch will actually be higher and anglers will enjoy the added bonus that the trout they catch will be 2 inches larger".
"Our four-year evaluation is the most robust and conclusive evaluation of our trout stocking program ever done in the history of IDFG. The results clearly show that in many Idaho waters anglers catch stocked 12 inch rainbow trout at a much higher rate than 10 inch trout. Without the cooperation of Idaho anglers, this study would not have been possible," said Fisheries Chief Ed Schriever. "We thank all of those who participated for helping us improve the effectiveness of our trout stocking program. I think anglers will enjoy the changes we are making to the stocking program as a result of the evaluation".
It is almost certain to be good for many businesses as well, since every dollar spent stocking trout in Idaho returns approximately $35 to the state's economy. The shift towards fewer, larger hatchery fish will continue over the next 18 months. By the summer of 2016, about half of the 800,000 pounds of catchable-size rainbow trout stocked in Idaho will be 12-inch fish.