Lake Pend Oreille, a significant body of water in northern Idaho, stretches nearly 50 linear miles and stands as the state’s largest lake. Formed by glacial activity, it is also one of the deepest inland lakes in North America. This expansive freshwater environment is renowned for its diverse fish populations, attracting anglers and researchers alike.
Resident Native Fish Species
Lake Pend Oreille is home to several fish species that are indigenous to its waters and surrounding tributaries. Among these are the Westslope Cutthroat Trout, recognized by the distinctive red slashes on the underside of their jaws and small, irregular spots. Historically, these trout were abundant, inhabiting most streams within the Pend Oreille basin.
Another native inhabitant is the Bull Trout, a species listed as “threatened” under the U.S. Endangered Species Act. These char are characterized by olive-green to brown backs and sides, adorned with light cream to crimson spots. Lake Pend Oreille holds the record for the largest bull trout ever caught, a 32-pound specimen landed in 1949. These fish undertake migrations between the lake and its tributary streams to spawn.
Mountain Whitefish are also native to the lake’s ecosystem. Historically, they supported a commercial fishery in the region. Other native species include the Northern Pikeminnow and Pygmy Whitefish, along with various cyprinids, catostomids, and sculpins.
Introduced Game Fish
Lake Pend Oreille’s reputation as a sport fishing destination is largely due to several species intentionally introduced over the decades.
The Gerrard strain of Rainbow Trout, also known as Kamloops, was first stocked in the lake in 1941. Originating from Kootenay Lake in British Columbia, these trout are well-adapted to cold waters. A world-record 37-pound rainbow trout was caught here in 1947, a size largely attributed to the abundant Kokanee salmon serving as a primary food source.
Lake Trout, or Mackinaw, were introduced to Lake Pend Oreille in 1925. These predatory fish can reach substantial sizes, with one notable catch weighing 43 pounds in 1995. Their population saw a significant increase starting in the late 1990s.
Kokanee Salmon, a landlocked variety of sockeye salmon, established populations in the 1930s, likely arriving from Flathead Lake during a flood in 1933. They quickly became a popular target for anglers and, more significantly, a fundamental prey base for the lake’s larger trout species.
Smallmouth Bass are a popular introduced game fish in Lake Pend Oreille, known for providing a spirited fight. These bass frequently inhabit rocky underwater ledges. Brown Trout are also present.
Other Established Non-Native Species
Beyond the primary game fish, Lake Pend Oreille hosts other non-native species that have established populations.
Lake Whitefish, distinct from the native Mountain Whitefish, were introduced as early as 1898 with the aim of creating a more accessible fishery. They tend to school in large numbers at depths ranging from 80 to 200 feet.
Yellow Perch are present in the lake. Northern Pike have also established themselves and are considered a concern due to their predatory habits. Walleye are a non-native species whose population has been increasing, prompting management attention due to their potential impact on other fish.
Additional non-native species found in Lake Pend Oreille include:
- Largemouth Bass, typically found in shallow areas
- Black Crappie
- Pumpkinseed Sunfish
- Brown Bullhead (a type of catfish)
- Tench
- Various Suckers
- Sculpins
Fish Management and Conservation
The fish populations in Lake Pend Oreille are actively managed by the Idaho Department of Fish and Game (IDFG). A significant focus of these efforts has been the recovery of the Kokanee salmon population, which experienced a severe decline in the early 2000s due to excessive predation. Through aggressive predator management, Kokanee numbers have largely rebounded, with millions of fry released annually through stocking programs. Fishing for Kokanee was temporarily closed in 2000 and reopened in 2013 following recovery.
A key component of this recovery has been the Lake Trout suppression program, initiated in 2006. This program aims to significantly reduce the Lake Trout population using various methods, including incentivized angling, trap netting, and gill netting. Over 240,000 Lake Trout have been removed through these efforts, which has positively impacted Kokanee, Rainbow Trout, and Bull Trout populations by reducing predation pressure. A bounty program of $15 per Lake Trout has also been implemented to encourage angler participation.
Managing invasive species is another ongoing challenge. Mysis shrimp, introduced in the 1960s with the intention of boosting Kokanee, instead competed for plankton and became a food source for Lake Trout, contributing to the Kokanee decline. More recently, the increasing presence of Walleye and Northern Pike has raised new concerns, prompting proactive management by IDFG. Efforts also extend to habitat protection, acknowledging the historical impacts of developments like the Albeni Falls Dam on fish migration and habitat. The overall goal of these management strategies is to sustain a healthy and diverse fishery, providing both recreational opportunities and conserving native species.