Bull Trout counts down in most Kootenai index streams
Koocanusa counts slightly up, but not enough to continue harvest fishery
by Montana Fish, Wildlife & Parks
December 4, 2011
Biologists have completed index counts of bull trout redds (nests) in nine standard stream index sections for the Kootenai River drainage populations for the 16th consecutive year. Bull trout spawn in the fall, building nests in tributaries during September and October. These counts serve as an index of how many migratory adult bull trout successfully spawn.
Crews also helped British Columbia biologists to survey index streams for the Koocanusa population in the Wigwam drainage. The same stream sections are surveyed annually and represent a known portion of the total bull trout spawning runs in each of the drainages. The 2011 count of 148 redds for non-Koocanusa index streams was less than in 2010 (187) and 78 percent of the 10-year average.
The Wigwam/Grave Creek counts are indices of spawners migrating upstream from Lake Koocanusa. This count was 1270 redds, which is slightly higher than 2010 (1238) but 68 percent of the average for the past decade.
The decline in bull trout redds in the Lake Koocanusa portion of the Kootenai drainage over the past several years caused Montana biologists to recommend changes in fishing harvest. Lake Koocanusa had been managed with a two bull trout per year fishing regulation from 2004 through 2009; the steady decline in redd numbers between 2006 and 2010 led to a reduction to one bull trout per year for the 2010 season. The continued lower than average redd counts and unknown impact of recreational angling in the British Columbia portion of the drainage led MFWP to recommend a shift to catch-and-release regulations (no harvest) starting in 2012 which was approved by the Montana Fish, Wildlife & Parks Commission at their meeting on November 10.
For more information contact Mike Hensler, FWP fisheries biologist in Libby at: 406-293-4161 (Ext 204); email: mhensler@mt.gov
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