Endemic Fish

The Bonneville cisco (Prosopium gemmifer) is one of three whitefish species endemic to (found only in) Bear Lake on the Utah-Idaho border. Bonneville cisco generally inhabit deep cool water. During their January spawning period, however, individuals move to shallow water, where they form large schools and spawn over the lake’s limited rocky areas.

Bonneville cisco eat small aquatic invertebrates. Individuals generally do not exceed 230 mm total length, and are easily distinguished from the other whitefish in Bear Lake by their pointed mouths, slender bodies, and absence of spots. Bonneville cisco are a popular ice-fishing target when the lake freezes during their spawning season in January and February. They are captured in great numbers through the use of dip nets and waders.

The Bear Lake Sculpin, also sometimes (incorrectly) known as the ‘bullhead,’ is an extraordinary fish found only in the crystal-clear waters of Bear Lake on the Utah-Idaho border. It plays a vital role in maintaining the lake’s aquatic ecosystem.

Feeding on various invertebrates, the sculpin serves as a crucial food source for both the native Bear Lake Bonneville cutthroat trout and the introduced Lake trout. By keeping the fish population healthy, it contributes to the overall balance of the lake.

During the breeding season from April to May, the sculpin gathers near the shoreline, engaging in a beautiful courtship dance. This annual ritual ensures the continuation of its species and adds to the lake’s vibrant biodiversity.

Recognizing the importance of the Bear Lake Sculpin, the Utah Division of Wildlife Resources has designated it as a Wildlife Species of Concern. This designation emphasizes the need to protect its natural habitat for future generations.

At Bear Lake Watch, we are committed to preserving the wonders of Bear Lake and its remarkable sculpin population. Join us in our mission to safeguard this magnificent lake and its unique inhabitants.

The Bonneville whitefish is a unique salmonid fish found exclusively in Bear Lake. As one of the three species of Prosopium endemic to Bear Lake, it holds a special place in the lake’s ecosystem. Classified as a Wildlife Species of Concern by the Utah Division of Wildlife Resources, the Bonneville whitefish is an important species that deserves our attention and protection.

In terms of appearance, the Bonneville whitefish shares similarities with its close relative, the Bear Lake whitefish. However, it can be distinguished by its more tapered nose and smaller scales. Younger fish display a pattern of spots that gradually fades as they grow. With reports of reaching a length of up to 22 inches and living up to eight years, these fish have a significant presence in the lake.

The Bonneville whitefish primarily inhabits the mid-levels of Bear Lake, where it feeds on chironomid larvae, pupae, and various insects. During the winter months, they may venture into shallower waters. Interestingly, older fish tend to move into shallow water more frequently than younger ones. The spawning season for the Bonneville whitefish occurs from mid-February through early March. Males accompany each female as she stops to spawn, resulting in a fascinating process that lasts a mere 5 to 15 seconds before the fish rejoin their school.

Although not highly sought after by anglers, some Bonneville whitefish are caught on hook and line, while others are captured through gill nets deployed at depths of 40 to 100 feet. Their unique characteristics and behavior make them a fascinating species to observe and study. At Bear Lake Watch, we are dedicated to defending species like the Bonneville whitefish and raising awareness about the importance of preserving Bear Lake’s diverse ecosystem.

The Bear Lake whitefish is a unique salmonid fish found exclusively in Bear Lake. It is one of three species of Prosopium that can only be found in this lake. The species is considered a Wildlife Species of Concern by the Utah Division of Wildlife Resources.

The Bear Lake Whitefish shares similarities with the Bonneville whitefish, but it can be distinguished by its Roman nose and larger scales. Unlike young Bonneville whitefish, it never develops spots. The Bear Lake whitefish tends to be smaller, reaching a maximum length of only 11 inches. It primarily resides in the deeper parts of the lake, where it feeds on various small invertebrates such as ostracods, copepods, and insects.

The spawning period occurs between late December and early February at depths of 50 to 100 feet. Due to its habitat preferences, it is rarely seen near the shore and is not commonly caught by hook and line.

The Bear River/Bear Lake Cutthroat Trout is an interesting subspecies with a unique biological history. Even though the present day Bear River terminates in the Great Salt Lake within the Bonneville Basin, these cutthroat trout actually evolved on a separate path from the basin’s native Bonneville cutthroat trout.

Geologic evidence suggests that the course of the Bear River was changed approximately 20,000 years ago due to volcanic activity. Before this rerouting, the Bear River was connected to the Snake River drainage. This is supported by DNA evidence which suggests that the Bear River/Bear Lake cutthroat evolved from their closest relatives, Yellowstone cutthroat trout, the native of the Snake and Yellowstone River drainages.

For a time, it was thought that due to commercial overfishing, the Bear Lake cutthroat had gone extinct from Bear Lake, and that non-native fish were all that could be found within Bear Lake’s waters. But due to conservation efforts beginning in the 1960s and hatchery supplementation programs starting in the 1970s, these cutthroat have made an amazing comeback in the lake itself and in many of its tributaries.

Bear Lake cutts are known for their voracious appetites and can grow to impressive sizes. Because of their piscivorous nature (meaning they feast on smaller fish) they have actually been utilized in lakes outside their native range to control invasive Utah chub populations. The most famous example of this is their use in Strawberry Reservoir. So while you are likely to catch Bear Lake cutthroat at Strawberry, do keep in mind that for the purposes of the Slam, fish must be caught within their native range. Therefore, cutthroat caught from Strawberry Reservoir and its tributaries cannot count towards your Slams.

*Many agencies still lump these cutthroat in with the Bonneville cutthroat, since today they all fall within the same Bonneville Basin watershed. But as mentioned above, Bear River cutthroat are genetically their own individual subspecies that evolved separately from Bonnevilles, and that probably justifies them to someday receive their own trinomial scientific name.