For the past six years, Utah wildlife officials have been fighting to control the growth of an invasive predator that has been multiplying in one of the state’s premier fisheries.
A new study under way now is aimed at tracking the movements and diet of the burbot, an eel-like fish that was illegally introduced into Flaming Gorge Reservoir in 2006 and is seen as a considerable threat to the trout and kokanee salmon that call the lake home.
The project, a cooperative effort between Utah State University, the Utah Division of Wildlife Resources, and the Wyoming Game and Fish Department, consists of placing nets in the water to catch the burbot. The fish are then implanted with ultrasonic telemetry tags that allow biologists to track their seasonal movements in an attempt to determine their spawning patterns. Burbot are known to multiply rapidly, with females laying as many as 1 million eggs per year.
In Utah, anglers are required to keep and kill all of the burbot they catch. Drew Cushing, warm water sport fisheries coordinator for the DWR, said anglers who catch a tagged burbot are encouraged to contact the DWR office in Dutch John as soon as possible.
“The telemetry tags we’re using are expensive,” Cushing said. “If you contact us, we can remove the telemetry tag from the fish and use it again.”
Craig Amadio, a biologist with the Wyoming Game and Fish Department, said the tags cost about $500 apiece, so any opportunity to reuse them will save a lot of money on the study.
The telemetry tags are embedded underneath the skin in the abdomen of the fish, but tagged fish can be identified by an external green tag. Anglers can either remove the tag and drop it off at the Dutch John office, or refrigerate the fish and schedule a time to meet with a biologist so the biologist can remove it.
Those who can’t bring the tag to the Dutch John office can call 435-885-3164 and provide the number on the external tag, the length of the fish, and the area on Flaming Gorge where it was caught. Tags can also be returned to the WGFD regional office in Green River, Wyo.
Amadio said the information gained from the research project will ultimately assist with burbot suppression efforts and the future management of the fishery. The ultimate goal is to identify when and where the burbot spawn. By knowing when and where the fish spawn, biologists and anglers can focus on those areas to maximize removal efforts and limit reproduction.
The diet portion of the study will help biologists better understand the current impacts burbot are having on other fish species in the reservoir and potential impacts the burbot might have in the future.
“Burbot are very aggressive predators and feed on anything they can catch,” Amadio said. “Crayfish appear to be their main prey source, but we have confirmed that they also feed on kokanee, rainbow trout and smallmouth bass.”
He said they also feed on the eggs of kokanee and lake trout while those species are spawning in the fall.
The project will end in early 2013. In the meantime, biologists are urging anglers who come across nets in the reservoir to leave the nets alone.
For more information about the research project, call the WGFD Green River regional office at 307-875-3223 or the DWR Dutch John office at 435-885-3164.