Coeur d’Alene Lake, a prominent body of water in Idaho, offers striking natural beauty and abundant recreational opportunities. Formed by ancient glaciers, this expansive lake stretches approximately 25 to 26 miles in length and boasts between 109 and 135 miles of shoreline. The Coeur d’Alene and St. Joe rivers feed into the lake, with its outflow forming the Spokane River. This article explores the diverse fish species inhabiting Coeur d’Alene Lake.
Native Fish Species
Historically, Coeur d’Alene Lake sustained thriving populations of native fish species, including Bull Trout, Westslope Cutthroat Trout, and Mountain Whitefish. Westslope Cutthroat Trout held historical importance for the Coeur d’Alene Tribe. Today, their populations have declined, with some found primarily in tributary streams. Migratory cutthroat trout navigate shallow bays near tributary mouths to access their spawning grounds.
Mountain Whitefish, another native salmonid, flourished in the cold, low-nutrient waters. Bull Trout are indigenous to the region’s cold, clear lakes, rivers, and streams. They have been listed as threatened under the Endangered Species Act since 1999. Their decline is attributed to habitat loss, fragmentation, and interactions with non-native species. These migratory fish typically spend several years in their birth streams before moving to larger lakes for feeding and overwintering.
Introduced Fish Species
Various fish species were introduced into Coeur d’Alene Lake, often to enhance recreational fishing. Kokanee Salmon, a land-locked sockeye salmon, were first stocked in 1937 and established a self-sustaining, naturally reproducing population. These fish primarily consume zooplankton and typically measure between 9 to 16 inches. Chinook Salmon were introduced in 1982, partly to manage the growing kokanee population, and also reproduce naturally. These salmon can grow to a considerable size, often ranging from 3 to 18 pounds.
Smallmouth Bass and Largemouth Bass are prevalent throughout the lake, with both species growing to impressive sizes. Smallmouth Bass prefer rocky banks and deeper sections, while Largemouth Bass thrive in shallower, vegetated backwater areas. Northern Pike, a large predatory fish, were illegally introduced in the 1970s. They often conceal themselves within aquatic vegetation in shallow areas, ambushing other fish, and prey on native Westslope Cutthroat Trout. Rainbow Trout are another introduced species.
Unique Aspects of the Fishery
Coeur d’Alene Lake has a reputation for producing exceptionally large, “trophy-sized” fish across several species. Anglers frequently report catching substantial bass, and a Northern Pike weighing 39 pounds once held the state record. The lake’s environment supports the growth of these large fish, making it a notable destination for anglers.
Kokanee Salmon in Coeur d’Alene Lake undergo a striking transformation during spawning. Immature fish are silvery-blue, but develop a vibrant red body and green head as they prepare to spawn, making them highly visible during upstream migrations. The lake’s varied underwater topography, including depths up to 192 feet and extensive shallow bays, creates a wide array of habitats supporting diverse fish populations. Bald eagles congregate in large numbers during winter to feed on spawning kokanee salmon. Sediment accumulation from tributaries and low dissolved oxygen pose ongoing challenges for some fish habitats.