Bonneville Whitefish (Prosopium spilonotus)

The Bonneville whitefish is a small to medium-sized salmonid with a streamlined, laterally compressed body typical of the Prosopium genus. Adults typically reach 8 to 12 inches in length, though some individuals may grow slightly larger. The body is silvery-white on the sides with a darker olive to bluish-gray back. The species exhibits small, irregular black spots scattered across the back and upper sides, which is the distinguishing characteristic referenced in its scientific name (spilonotus means 'spotted back'). The head is relatively small with a subterminal mouth, meaning the snout overhangs the lower jaw. Fins are generally clear to dusky, and the adipose fin characteristic of salmonids is present. The lateral line is complete and nearly straight. During spawning season, males may develop subtle breeding tubercles. The Bonneville whitefish closely resembles other Prosopium species but can be distinguished by its spotting pattern and geographic distribution limited to the Bonneville Basin.