The Utah Division of Wildlife Resources recently stocked Scofield reservoir with tiger trout. This is a new species at the reservoir. Tiger trout are a sterile hybrid, developed by combining the eggs of a female brook trout and the milt of a male brown trout. Because of their sterility, tiger trout grow fast, putting its energy into growth rather than reproduction.
Around 80,000 tiger trout were planted in Scofield in early September. These could be nine to 10 inches by next fall.
The DWR has witnessed tremendous growth rates of tigers in other reservoirs. In Duck Fork reservoir, some tigers grew 12 or more inches in a single year. That's about double the growth of a rainbow trout.
The reason for introducing another trout is not entirely for sporting reasons. In the spring of 2005, DWR biologists discovered chubs in the gill nets. This is the first time this species has shown up since the reservoir was treated in the early 1990s to remove undesirable fish populations, including the chub. Anglers using live chubs as bait, brought them back to Scofield. The practice of using live fish as bait is illegal. The discovery of chubs in Scofield is potentially catastrophic for the fishery indicated the wildlife agency.
Utah chubs are extremely prolific. They reproduce rapidly and can out compete game fish in a flat water fishery. Abundant chubs in Joe's Valley reservoir have prevented the fishery from reaching its full potential. While trophy splake are readily available, much of the productivity of the system is tied up in chubs.
Scofield is among the four top fisheries in Utah. Losing the fishery to an invasion of chubs would prove devastating explained the wildlife group.
Chubs are commonly found in shallow water and often inhabit shoreline zones, where they consume food and occupy space needed by young trout. As trout grow up, they often move to deeper, cooler water and lose contact with the chubs. This is an advantage to chubs, because they are less vulnerable to attack from larger fish.
Tiger trout are fish eaters from an early age. They seem willing to hunt for prey in shallower waters than some other trout subspecies. Fisheries managers hope that tigers will keep the chub from out-competing and overrunning other fish in the reservoir.