Wyoming Game and Fish Department biologists will resume tagging Grand Teton National Park lake trout with reward tags worth $25.

The program, restricted to Jackson Lake, gives anglers an incentive to report their catches and helps the department track growth rates and mortality of the nonnative trout. Netting and tagging, going on since 1988, occurs each fall when the deepwater trout head to shallower water to spawn. This year’s tagging, which runs from Sunday to Tuesday, will target mackinaw over 20 inches. Tags are attached behind the dorsal fin.

Because of variable conditions, the number of reward tags inserted each year varies greatly, said Rob Gipson, Game and Fish’s Jackson Region fisheries supervisor.

“It can range from 25 to over 100,” Gipson said. “We only set the net for an hour to reduce mortality of these larger fish. It takes a lot of time.”

In 2011, 66 new tags were attached to Jackson Lake mackinaw. Since the program began, more than 700 fish have been tagged. 

Thirty tagged fish were captured at some point in 2011, but seven of those were caught by Game and Fish officials during netting operations to set new tags.

The reward numbers, though, are a bit skewed by an unnamed fisherman who’s apparently good with the rod and not short on cash.

“There’s a person in town who catches probably 10 fish a year,” Gipson said. “He doesn’t collect the money, but tells us the length and weight and tag number.”

According to a Game and Fish newsletter, a 2007 study showed that lake trout growth in Jackson Lake is very slow. Mackinaw take up to 10 years to grow to just 20 inches. Reward tag information shows the average growth rate above 20 inches is just more than  half an inch a year.

Lake trout, however, have swarmed Jackson Lake waters for more than a century, and some lunkers do exist. The 2011 spawning and tagging sample turned up a 42.5-inch, 38-pound female.

Since July, just eight reward tags have been turned in, Gipson said.

The number could jump before ice-over, but not until the end of the month at the earliest. Jackson Lake is closed to fishing from Oct. 1 to Oct. 31 to protect spawning lakers.