Montana bull-trout count murky this year
High stream flows led to a murky bull trout redd count this fall that exceeded last year's numbers for the Flathead and Swan basins, according to Montana Fish, Wildlife and Parks.
By JIM MANNThe Daily Inter Lake
High stream flows led to a murky bull trout redd count this fall that exceeded last year's numbers for the Flathead and Swan basins, according to Montana Fish, Wildlife and Parks.
Fisheries biologist Tom Weaver said the counts are "absolute minimums" because of high-water conditions in September.
"The flows were extremely low prior to spawning and the fish were running into beaver dams, because there hadn't been any flows to blow them out," he said. "When the fish finally did spawn, then it started raining and the opposite happened. The streams came up … and when high flows come, you lose the definition of the redds so they're really hard to see."
Redds are distinctive cobbled spawning beds that bull trout make in stream bottoms for their eggs.
State biologists, led by Weaver, have been counting redds in the Flathead basin since 1980, in the Swan basin for the last 24 years and in South Fork upstream from Hungry Horse Reservoir for the last 13 years.
The counts have become important indicators for bull trout population trends since the species was listed as threatened in 1998.
The redd count for fish migrating from Flathead Lake came to 144 in established index stream sections. Last year's count was 136.
The count in Middle Fork Flathead River tributaries came to 56 this year, compared to 47 last year and a high of 194 in 1982.
The redd count was low in tributaries leading to the North Fork Flathead River. This year's count of 88 was comparable to 89 last year, but both are far below the peak of 406 counted in 1982.
The most troublesome stream for the past decade has been Coal Creek, which this year had just 4 redds.
Weaver said index sections in the Flathead basin are calculated to account for 45 percent of the total spawning habitat used by bull trout in the basin. That suggests a basinwide total of 300 redds.
In the Swan Lake basin, the redd count on four stream index sections was 402 this year, compared to an average of 430 over the last three years.
"But again, we had those bad conditions, so it's pretty likely that this year was pretty similar to the last three years," Weaver said.
There were multiple occasions where biologists suspected they were looking at redds, but they could not include those in the count because of the lack of clarity in the water.
That happened repeatedly in the South Fork Flathead River basin above Hungry Horse Reservoir. At Sullivan Creek, it took three separate trips to the field to carry out an adequate count.
The Sullivan Creek count came to 24 compared to 62 last year, while the South Fork count, which includes tributaries outside the Bob Marshall Wilderness Complex, was 64 this year compared to 98 last year.
A count of 102 in 1993 was the highest since the state started monitoring bull trout reproduction above the reservoir.
Redd counts are carried out every three years inside the wilderness; this year they were not.
Reporter Jim Mann may be reached at 758-4407 or by e-mail at jmann@dailyinterlake.com.