Heeding the trend, Mosley proposed the mandatory "catch and kill" regulation last spring on northern pike, walleye and smallmouth bass on the Green for the roughly 30 miles it flows from the dam to the Colorado border.
Pike are well known for being a tough fish to catch, but that has not been the case for some Green River anglers recently.
Darren Bowcutt, lead guide for Western Rivers Flyfisher, decided to target the long, toothy predators last week with a fly rod and was rewarded with fun fights, memorable pictures and tasty fish tacos.
"We caught five in two days, missed a couple and saw others," Bowcutt said of the pike excursion he and others set out on late last week. "I hooked one earlier in the week and his teeth clipped the line. We went back with steel leader [the part of the line attached to the lure or fly] and that's how we caught them."
Bowcutt cleaned and then grilled four of the fish, and gave the other one to Mosley. Two of the pike he cleaned had trout in their stomachs, the other two and the one given to the biologist had empty stomachs.
Mosley is not overly concerned that current pike, smallmouth bass and walleye numbers will impact a very healthy brown and rainbow trout population estimated at roughly 20,000 fish per square mile in the upper reaches, but they could if left uncontrolled.
He is also supporting the efforts by his colleagues to control the same species lower on the Green River after it flows back into Utah near Jensen where fish on the Fish & Wildlife Services' Endangered Species list are threatened.
"Removing pike and the other fish is one of our main goals for endangered fish recovery on the Green," said Matt Breen, native aquatics project leader for the Utah DWR.
The razorback sucker, pikeminnow, bonytail chub and humpback chub are all fish found in the Green and listed as endangered. The roundtail chub, flannelmouth sucker and bluehead sucker are fish recognized by Utah as "sensitive species."
Breen says the massive flows on the Green from Flaming Gorge Dam in 2011 led to a successful pike spawn which, in turn, led to more fish in the upper stretches as the fish sought to expand their range.
Breen and other biologists are working to control pike, walleye and bass populations on the river near Jensen by placing nets and electroshocking in areas where the fish congregate to spawn.
The efforts have been taking place each spring since 2001 with notable results, but it only takes one good reproduction year to turn the tide.
"We removed just under 400 pike, many of them over 30 inches, last year," Breen said. They grow fast and out compete, as well as eat, the fish on the endangered and sensitive species' lists."
Removing the fish by any means is something the biologists say should be done to protect the sportfish of the upper portion of the Green and the native species near Jensen.
The "catch and kill" regulation went into effect on Jan. 1 and it didn't take long for an angler to be the first known to catch a pike in 2013. Unfortunately, he didn't know about the rule and let the 26-inch fish back into the water just below the dam where he caught it.
Fortunately, other anglers heard about the fish and targeted it below the dam. Mosley said the pike was caught last week and removed from the river.