While there are those who might look down their nose at the Rocky Mountain whitefish (Prosopium williamsoni) or mountain whitefish as they are sometimes referred to, I for one have spend many a pleasant afternoon and evening casting to these too often maligned members of the Salmonidae family.
Mountain whitefish are widely distributed western North America. They can be found from the Mackenzie River drainage in the Northwest Territories, south through western Alberta and British Columbia and down into the warts of northwestern USA, as well as in the drainages of the Hudson Bay, the Columbia River, the upper Missouri River and upper Colorado River. By and large they are opportunistic feeders that will readily go after any and all manner of insects and/or invertebrates that drift past close to bottom.
The body shape of mountain whitefish is superficially similar to members of the minnow family (cyprinids) although they can be distinguished by the adipose fin common to salmonids. The body is slender and nearly cylindrical in cross section, generally silver in colour with a dusky olive green shade dorsally. They have a short head with a small mouth underneath the snout. A mature mountain whitefish living in BC’s colder fresh waters will tend to be in the one to two pound, 12 to 15 inch range, although a specimen was recorded that weighed 2.9 kilograms or 6.4 pounds and 70 centimetres (28 inches) in length.
One of the best things about fishing for mountain whitefish is their sheer abundance. They also tend to be eager and aggressive feeders and can provide a more than worthwhile fishing opportunity, especially for young and/or neophyte anglers … not to mention more seasoned anglers who might be looking for action when more sought after sport fish such as trout are not actively feeding.
Mountain whitefish prefer the cold clear waters of mountain streams and lakes, favouring large deep pools of at least a meter in depth. They are bottom feeders that feed by stirring up the substrate with their pectoral and tail fins to expose insect larvae and other invertebrates, including snails, crayfish and amphipods, and, although they most frequently feed in the lower strata of streams, they will also often rise to the surface to feed on hatching insects. Anglers using fly fishing gear can hook mountain whitefish using small weighted nymphs such as the Pheasant Tail, Prince Nymph and Gold-ribbed Hare’s Ear. They can also be taken on spinning gear using tiny spinners and streamers, or, on spinning gear using a float with a nymph pattern just off the bottom.
Angling for mountain whitefish is pretty straightforward, given their preference for sub-aquatic insect forms, one need simply to get a nymph pattern down toward the bottom where they tend to hold, waiting to eagerly for whatever food source might come floating by. There are a number of ways to present a nymph pattern. One of my favourite methods is to use my ultra-lite centrepin outfit to cast a small balsa wood slider type float with a nymph pattern suspend at just the right depth. I simply cast the rig upstream, giving the fly enough time to sink to the bottom before it drifts past the fish. If casting a fly rod on rivers or larger streams, I’ll use a nine foot, five weight rod with a sinking line or a floating line with a sink tip. When using spinning gear, I prefer to use a seven to eight-and-a-half foot, light to medium light, fast action spinning rod with six or eight pound monofilament line. On smaller creeks and streams, I’ll use my four weight fly rod or a six foot light action spinning rod and four pound mono. Spinners such as small Panther Martins or Mepps, as well as small spoons such as Dick Nites and silver Len Thompsons work well.
Mountain whitefish tend to take any offering with several quick sharp, but also quite light bites. To detect a bite, simply keep a finger on the line and be ever alert for their distinctive tap, tap, tap. When you feel a tap or two, set the hook. It is important to remember that mountain whitefish have very soft mouths, so it is important to always use a somewhat softer hookset.
Like I said, some anglers may look down their nose at casting for mountain whitefish, but I’ve had a lot of fun catching and releasing them. Sometimes quantity is better than quality – especially when the quality isn’t biting.