Gerrard Rainbow Trout Fishing — Kootenay Lake
The Gerrard rainbow is Kootenay Lake's headline fish — a wild, kokanee-eating strain that historically grew to around 35 pounds, the largest rainbow trout on earth. It is a trolling and charter fishery more than a fly-cast one, and today it is also a fishery in managed recovery. Here is what the fish is, how the lake is actually fished, and the Region 4 rules that come with it.
Gerrard rainbows are a wild strain native to the West Kootenay, named for the old Gerrard townsite on the Lardeau River — the strain runs up the Lardeau toward Trout Lake to spawn, then returns to Kootenay Lake to hunt. Unlike a stocked stillwater rainbow, a Gerrard is a piscivore: it lives on kokanee fry, and its size tracks the kokanee base almost directly. That diet built the legend — fish to roughly 35 pounds, historically the largest rainbows anywhere.
Be honest about the present tense, though. DNA-confirmed sampling in 2023 found the Gerrards have shrunk to sizes typical of other BC lakes — the predator population outgrew its kokanee prey. Treat ~35 lb as the historical ceiling, not today's average. The full biology and the size caveat live on the Gerrard rainbow trout species page.
Kootenay Lake is a 104 km fjord-like trench between the Selkirk and Purcell ranges, and the Gerrard fishery is a boat fishery. The shorelines drop away fast, the fish range the open water column, and the productive game is downrigger trolling — spoons, plugs and bucktails run at the depth where the kokanee schools hold, often from a guided charter. Krocodile spoons, Apex Hot Spots, Tomic and Lyman plugs and trolled bucktails are the standard hardware; run bigger lures at a faster troll (3–7 kph) to fish past the kokanee and into the rainbows shadowing them.
Season matters more than spot. The rainbows ride near the surface from autumn through late spring, then drop deeper in summer heat — so the classic trophy window is the cold half of the year. Fly anglers are not shut out entirely: creek mouths and estuary flats in the cooler shoulder seasons can bring fish within casting range, and the traditional surface-trolled Kootenay bucktail is itself a fly, fished behind a boat. But for the marquee Gerrards, the boat and the rigger are the tools. From the Creston end, Kuskanook Harbour is the closest launch, with Boswell down the east shore and a string of ramps north from Balfour to Lardeau. The lake's full profile is on Kootenay Lake.
Everything about the Gerrard fishery pivots on kokanee. The system was knocked off balance through the mid-twentieth century — invasive Mysis shrimp arrived in 1949, and the Duncan (1967) and Libby (1973) dams stripped nutrients from the inflows — and the kokanee crashed, taking the trophy fishery with them. Since 1992 on the North Arm and 2004 on the South, the province's Nutrient Restoration Program has added measured nitrogen and phosphorus to rebuild the food web by hand. Recovery is real but partial: about 63,300 kokanee spawners returned in 2019, and Meadow Creek's spawning channel alone counted 71,423 in fall 2023 — the best in a decade, still short of historic highs.
Because the predators overshot the prey, anglers are asked to be part of the fix. The Kootenay Lake Angler Incentive Program rewards the harvest of rainbow and bull trout — turn in the heads and you're entered in a prize draw — to ease predation while the kokanee climb back. On most trophy water you release the big fish; here, keeping a rainbow can be the conservation-minded choice.
These are the Kootenay Lake rainbow rules as the region's notes record them from the Region 4 synopsis (2025–2027). Recovery management can force in-season changes, so confirm the current details against the official BC freshwater regulations synopsis before you fish.
- Main body daily limit. Rainbow trout daily limit is 10, any size — a deliberately high quota that supports the harvest push.
- Conservation Surcharge Stamp. Required to keep a rainbow over 50 cm; the annual limit on stamped fish is 20.
- Upper West Arm. Rainbow catch-and-release January 1 to May 31.