Jackie Watson pulled the metal tub loaded with dead fish and tangled netting of the Utah Division of Wildlife Resources boat and set it on the asphalt of the Sailboat Beach parking lot at Deer Creek Reservoir State Park.
Watson, a DWR Blue Ribbon fisheries biologist, proceeded to pull the netting out of the bucket and stretch it across the pavement, pulling the tangled aquatic lifeforms with it. A team of a half dozen DWR biologists and fishery technicians then moved in to start untangling the fish.
The purpose of this morbid process, which took place Tuesday morning, was to survey fish populations in Deer Creek Reservoir, a popular fishing spot for anglers in Wasatch and Utah counties.
On Monday, the team set up 6-foot tall, 80-foot long gill nets, a thin mesh netting used by both commercial fishers and wildlife researchers to catch fish, in the water perpendicular to the reservoir’s shoreline.
They returned early Tuesday to pull out the nets and count and record the dozens of fish whose gills became entangled in the netting and suffocated.
At 10 a.m., dozens of cloudy-eyed fish were lined up in 80-foot rows in the reservoir parking lot, including walleye, rainbow trout, brown trout, small and largemouth bass, Utah sucker and black crappie.
“Our goals are just monitoring the fish community, and the gill nets are one of the methods we use to monitor the fish community,” Watson said. “They don’t target any specific species, but they do target fish that swim around the shoreline.”
Through this sampling process, which occurs approximately once every three years, wildlife officials are able to gather data on species composition, health and population, which is then used to determine which fish species need to be restocked or monitored.
A fish’s stomach contents, for example, reveal what the fish had eaten. Likewise, a fish’s length and weight can be used to determine whether the animal is healthy.
“So we get a lot of information out of this data,” said Watson. “And then we use that to make management decisions.”
Additionally, the DWR guts the fish and donates the fillets to the public, according to Watson.
The gill-netting process upsets some anglers, the DWR biologist acknowledged, who “think that we’re depleting the population or killing all the fish.”
“I think the key is it’s a sample of the population,” Watson said. “And it’s indicating what’s going on with the population. You’re sacrificing the few to understand all of them.”
It is only one of multiple methods wildlife officials use to sample fish populations, she added, pointing to electrofishing and angler surveys as alternatives.
By 10:30 a.m., most of the fish had moved from the parking lot to a nearby pavilion, where the DWR team arranged themselves in a kind of dead fish assembly line in order to most efficiently measure, gut and fillet the fish.
Sierra Bailey, a seasonal DWR employee, weighed a walleye on a hanging scale and handed the fish off to DWR regional aquatic manager Mike Slater, who sliced it open and commented on the unspecified contents of its stomach.
“Walleye. Female. Unidentified fish,” Slater said before grabbing another fish. “Sterilized female. Stomach is empty. Your next walleye has seven sunfish in it. It was a male.”
As Watson jotted down the data on a clipboard, wildlife technician Mike Packer dug his knife into the spine of a walleye before filleting it and tossing its remains into an orange biohazard bag.
“Skin on or skin off on these walleye?” asked Packer. “Does it matter?”
“I take them off,” Slater replied. “I’ve just never used the walleye with the skin on.”
In addition to Deer Creek Reservoir, the DWR central region office also periodically surveys fish using gill netting at Utah Lake, Yuba Lake and Jordanelle Reservoir.