Utah Chubs are one of the few species of fish present in Utah that are actually native to the state. They evolved alongside the Cutthroat Trout and are an important food fish where they still coexist.
Utah Chubs are a nongame species of fish, and therefore the taking of them is not regulated. You can keep as many as you like. The smaller ones make excellent bait for catfish, cutthroat trout, walleye, pike, and many other predator fish.
It shouldn't be too hard to catch chubs in waters where they are present in significant numbers. They'll find you. They are notorious for stealing bait, hitting lures and flies, and getting caught accidentally when anglers are targeting other species such as trout or bass.