Bear Lake, straddling the Idaho-Utah border, is often referred to as the “Caribbean of the Rockies.” This nickname comes from its striking turquoise-blue waters, a coloration attributed to the refraction of light off suspended calcium carbonate deposits. With an average depth of 94 feet and a maximum depth of 208 feet, it stands as the second-largest natural freshwater lake in Utah. The lake’s unique properties have fostered a diverse fish population, including species found nowhere else.
Unique Native Fish of Bear Lake
Bear Lake is home to four fish species found exclusively within its waters. These endemic species are the Bear Lake Sculpin, Bonneville Cisco, Bonneville Whitefish, and Bear Lake Whitefish.
The Bear Lake Sculpin (Cottus extensus) is a small, mottled brown fish, typically measuring between 3 to 6 inches in length. It inhabits the lake’s bottom, often found in deeper areas ranging from 30 to 100 feet. This sculpin feeds on aquatic invertebrates and zooplankton, serving as a food source for larger fish, including native cutthroat trout and introduced lake trout. During the spring, from April to May, adults move into rocky areas near the shoreline to spawn.
The Bonneville Cisco (Prosopium gemmifer) is a slender, pearly-silver fish, generally not exceeding 9 inches in length, distinguished by its pointed mouth and lack of spots. These fish primarily consume small aquatic invertebrates found in the water column. While they typically reside in deep, cool waters, they form large schools and move into shallow, rocky areas to spawn from late December through January. This spawning behavior makes them a popular target for ice fishing.
The Bonneville Whitefish (Prosopium spilonotus) can grow, reaching up to 22 inches and living for about eight years. Younger Bonneville Whitefish exhibit spots that gradually fade as they mature. This species feeds on chironomid larvae, pupae, and various insects, inhabiting the mid-levels of the lake for much of the year. During the winter months, they venture into shallower waters for spawning, which occurs from mid-February to early March or from November to mid-December.
The Bear Lake Whitefish (Prosopium abyssicola) rarely exceeding 9 inches, with a maximum recorded length of 11 inches. It is identifiable by its “Roman nose” and larger scales, and notably, it never develops spots. This species prefers the deeper, colder parts of the lake, typically residing at depths of 50 to 100 feet. Its diet consists of small invertebrates such as ostracods, copepods, and other insects. Spawning takes place in these deep waters from late December to early February, or sometimes extending from February to May.
Introduced and Commonly Fished Species
Beyond the native species, Bear Lake also supports several introduced fish populations popular with anglers. These species were often introduced to enhance recreational fishing opportunities within the lake.
Lake Trout (Salvelinus namaycush) were introduced into Bear Lake around 1911 to bolster sport fishing. These fish inhabit the deep, cool waters of the lake and are known for their potential to grow quite large, with some specimens exceeding 30 pounds. Lake trout are characterized by their gray-brown coloration, light spots, and a deeply forked tail fin. Anglers pursue them throughout the year, often employing downriggers with various lures like spoons or rapalas.
The Cutthroat Trout (Oncorhynchus clarkii), specifically the Bear Lake strain of Bonneville cutthroat, is a native and highly sought-after sport fish. These trout are recognized by a distinctive crimson slash on their lower jaw, along with orange pelvic and anal fins and large round spots on their upper body. They can attain considerable size, with the Idaho state record of 19 pounds caught in Bear Lake. Cutthroat trout typically migrate to tributary streams to spawn from mid-April through June.
Rainbow Trout (Oncorhynchus mykiss) have also been introduced to Bear Lake. While they are present, their natural reproduction within the lake is limited. Rainbow trout often hybridize with the native cutthroat trout, creating mixed-species offspring. Despite stocking efforts, the return rate for planted rainbow trout has historically been low. They are less prolific than they once were but can still provide an occasional catch for anglers, particularly in the lake’s tributaries.