June floodwaters that tore apart streambeds, tossed boulders and uprooted trees along creek banks appear to have spared a portion of Banff’s sensitive bull trout population.
Parks Canada biologist Shelley Humphries discovered several healthy specimens had returned to an important spawning stream earlier this summer and appear ready to lay their eggs.
Humphries travelled deep into the backcountry earlier this month to monitor the stream for bull trout. Although it’s impossible to extrapolate the findings to give a park-wide picture, she believes population levels in the creek are promising.
“It was a pretty tough summer for fish in Banff. Any of the spring spawning species would have lost their eggs. I was worried. We have seen some major changes on the upper Bow and had some flooding on the upper tributaries,” Humphries said.
To her delight, she found several large bull trout in the region spanning between 60 and 70 centimetres in length. The flood waters did not change the features of the creek, and the conditions still look good for spawning.
“At minimum, the flooding did not affect some of our large fish.”
Bull trout are picky about their spawning locations. They need groundwater upwelling (groundwater rising from the bottom of a stream) and well-oxygenated water with the proper-sized gravel bottom in order to raise their young. There are only a handful of known locations on Parks land where these conditions exist, and the flood didn’t alter this one.
“There are not many places bull trout can find the right conditions for spawning. They come from parts of the Bow and Banff and move in on one location,” Humphires said.
Bull trout numbers have never been counted in Banff National Park, although they are definitely a species in trouble. Bull Trout are protected provincially and the federal agency responsible for endangered species (COSEWIC) recommended they receive a “threatened” listing from the government.
Humphries hopes that means more funding will become available to monitor and save bull trout populations, which in the past have suffered from over-fishing, and were once considered a nuisance fish by anglers. They’re also competing with non-native fish species. Susceptible to angling, they historically live in large lakes, but are becoming harder and harder to find.
“Bull trout have been protected for a long time, but we’re still seeing regional declines,” Humphries said. “We don’t have a great understanding of where they are, and fish monitoring is expensive and time consuming.”
Bull trout are easy to identify with their grey and silver colours. They have no black on their bodies at all, hence the Rocky Mountain fishing rule – if there’s no black, throw it back.
The COSEWIC listing is a two-part process. Now that biologists have recommended the species receive threatened status, politicians must now agree to do the same. The process is long and unpredictable. For example, COSEWIC first recommended cutthroat trout receive a threatened status in 2006. They didn’t get full approval until 2013.
“Provincially, the species is recognized as having problems. Federal assessments are a two-step process. The first comes from technical specialists and fisheries professionals. They work with regional biologists, who make a recommendation to the federal government, who then deliberate to see if more data is needed or if it’s accepted as is,” Humphries said.
