Lake trout (Salvelinus namaycush) are not evil. Lake trout are weeds, a pelagic version of spotted knapweed. Weeds do fine in their native habitat, they have predators and natural controls that keep them in control. Outside their natural range, weeds and lake trout alike tend to decimate local populations. Lake trout out-compete, outlive and consume native species. We spend millions every year to control invading weeds and save natural habitats. Fish seem to be different. Once lake trout become established they tend to develop a constituency. Fishermen fear that if we try to eradicate the invaders, fishing opportunities and fish populations will decline. Just the reverse is actually true.
Lake trout are native to a small part of Montana. Following the last glacial retreat, isolated populations of lake trout remained in a few lakes that drain into Hudson Bay. In the past century, lake trout have been legally and illegally introduced into many waters throughout the West. In order to salvage populations of native fish, several large projects are now underway to reduce populations of invasive lake trout. Millions of dollars have been spent to net lake trout from Yellowstone Lake where their presence in only the last two decades has reduced one of the last strongholds of Yellowstone Cutthroat Trout to less than 10% of its historic population. Lake trout were introduced into Lake Pend Oreille in northern Idaho in 1925, but only in the last decade has their presence, along with other factors, led to declines in Kokanee salmon populations along with reductions in native trout species. In Flathead Lake, Montana Fish, Wildlife and Parks now estimates that the lake trout population has reached nearly 400,000 fish in the lake and native bull trout have declined to only 3,000 to 4,000 in the entire drainage. An experimental lake trout netting program was begun in Swan Lake last year that will, hopefully, show positive results in one of the better strongholds of bull trout in northwest Montana. Glacier National Park has seen populations of it’s native fish in precipitous decline along the western slopes due to invasion by lake trout from Flathead Lake. The Park has committed to netting lake trout in Quartz Lake where they believe that they have a reasonable chance of saving a small, distinct native bull trout population.
The time has come to make a tough decision on how to deal with lake trout in Flathead Lake. Following the crash of the kokanee population during the 1980s, due in part to the introduction of opossum shrimp, lake trout numbers have exploded leaving native populations of bull trout and cutthroat trout on life support. Flathead Lake is co-managed by Montana FWP and the Confederated Salish and Kootenai Tribes. So far, lake trout control has relied on sport fishing through both fishing contests and regular fishing. Conventional wisdom among fisheries managers maintains that a population reduction of at least 50% is needed to affect any meaningful reduction in fish populations. Current techniques have removed only 40,000 to 50,000 fish annually with no noticeable affect on the lake trout. Since 1998, western bull trout have been listed as threatened under the Endangered Species Act. Recent bull trout redd counts in all Flathead River tributaries continue to show that the precarious populations are headed toward a local extinction. We must act and act soon. It is time to take the next logical step and move toward a lake trout netting program on Flathead Lake to reduce lake trout numbers. We cannot allow a burgeoning population of invasive species in the big lake to continue to endanger our native fish throughout the entire drainage.
According to MTFWP, the crash of the kookanee and bull trout populations led to a reduction in fishing interest in Flathead Lake from over 89,000 angler-days in the 1980s to around 54,000 angler-days currently. Some would say that anglers only want to catch fish and don’t really care about the type of fish they catch. That seems to me, akin to saying that hunters would just as soon shoot Jersey cows as elk since they are easier to kill and provide more meat. Fishermen are interested in the overall health the local environment. As we have seen in other areas, fishermen are drawn to healthy waters with vibrant multi-species fishing opportunities. Allowing bull trout to decline further could result in severe federal fishing restrictions under the ESA. Removing a few more lake trout will not affect fishing opportunities, it will only add diversity along with protecting our native fish.
We can never fully remove lake trout from Flathead Lake any more than we can completely eradicate spotted knapweed from Montana, but we can reduce this threat to Montana’s indigenous fish and hopefully give our native species a chance to thrive into the future. We simply can’t stand by and watch as individual genetic components continue to “blink out” due to a basin-wide contamination from Flathead Lake. Contact Montana Fish, Wildlife and Parks and let them know that you are interested in the health and strength of our native fish populations and that you support reducing lake trout numbers in Flathead Lake.
FWP Region 1 Headquarters
490 North Meridian Road
Kalispell, MT 59901
Phone: (406) 752-5501
Fax: (406) 257-0349