This fall’s bull trout spawning was 78 percent of the 10-year average in streams feeding Montana’s Kootenai River below Libby Dam, and 70 percent of the 10-year average in streams feeding Lake Koocanusa north of the dam.
Montana Fish, Wildlife and Parks biologists counted bull trout redds, or spawning nests, in the same Kootenai Basin stream sections for the 16th consecutive year during the September-October spawning run.
This year’s counts of 148 redds in 11 spawning streams below Libby Dam was lower than last year’s count of 187 redds and 78 percent of the 10-year average of 239 redds.
Montana biologists assisted counterparts in British Columbia to count redds in the transboundary Wigwam drainage, one of the busiest bull trout spawning areas in North America. This year’s count of 1,206 redds in the Wigwam drainage was ahead of last year’s count of 1,118 but was still 72 percent of the 10-year average of 1,663 redds.
Redd counts were also conducted in Montana’s Grave Creek drainage, which is used by Lake Koocanusa bull trout. Combined, the Wigwam and Grave Creek counts of 1,270 redds was 70 percent of the 10-year average of 1,825 redds.
A decline in redd counts in both drainages over the last few years prompted Montana biologists to recommend changes in fishing regulations that had allowed angler to keep two bull trout per year from Lake Koocanusa. Last year, that limit was lowered to one bull trout and a change to catch-and-release only regulations for 2012 was approved by the Montana Fish, Wildlife and Parks Commission on Nov. 10.