Gerrard Rainbow Trout Kootenay Lake BC
Rainbows: World’s Largest Trout
Kootenay Lake, British Columbia, land of giants. Giant trout, that is – colossal rainbows, known as Gerrards, that weigh in at 5 times the normal size of Kamloops trout. The secret of their super-size: ideal spawning conditions on a short, gravelly stretch of the Lardeau River, a tributary of Kootenay Lake, and a rich, gourmet diet of Kootenay Lake kokanee salmon.
The Gerrard trout, named for a small community on Trout Lake, at the head of the Lardeau River, is a genetically gargantuan strain of rainbow trout that averages 6.8 – 9.03 kilograms in weight, compared to the 1.3 – 1.8 kilogram average for the standard Kamloops variety of rainbow trout found throughout interior British Columbia’s lakes and rivers. (Rainbows are a landlocked version of sea-going steelhead trout, and share the same species classification.) The Gerrard strain spawns and rears in spring on a single 300 metre stretch of the Lardeau River, producing fish that have been known to reach up to 20 kilograms in weight. (The largest Gerrard ever landed is said to be a 23.6 kilogram fish caught in British Columbia’s Jewel Lake in the 1930’s.) Gerrards also live longer than other rainbows – up to 8 years, compared to an average lifespan of 5 – 6 years for standard Kamloops trout.
Unlike other rainbows, whose diet consists of invertebrates, crustaceans, insects and eggs of other fish, Gerrard trout feed mainly on kokanee, Kootenay Lake’s landlocked version of the sockeye salmon. While this privileged diet helps them to grow big and strong, it was threatened during the early 1900’s by a drastic decline in the Lake’s kokanee population (See “The Ups and Downs of the Kootenay Lake Kokanee”.) Recent indications of a resurgence of Kootenay Lake kokanee bode well for the giant Gerrards.