Coastal cutthroat trout have become harder to find at Nanaimo's Walley Creek, which has prompted the Nanaimo Area Land Trust, along with other local groups, to begin research into several of the region's creeks to see if they can find evidence of the trout.
Linda Brooymans, NALT's stewardship manager, said the project stemmed from the creek's decline.
"We had a report in 2004 that basically said, in the lower parts of Walley Creek that were good fish habitat, you had trout in every pool," she said. "This year we caught no trout and in 2021 we caught two – this was from 60 trout to two."
This prompted NALT, with funding from the Freshwater Fisheries Society of B.C. and support from the B.C. Ministry of Water, Land and Resource Stewardship as well as the City of Nanaimo, to work with other local groups to search for cutthroat trout populations across local creeks.
"We're trying to see the distribution presence, whether there's cutthroat trout specifically or not in these streams and also where are they in the streams, how far up and how far down," said Joe Clark, a VIU biology student working with NALT on the project. "We're going to take that information and we're going to try to put it into a map layer that will be publicly available so that information can be seen and give a better understanding of the distribution, because right now there isn't a solid understanding of where the fish are, especially in these smaller streams and the urban streams."
On Tuesday, Oct. 1, a Brannen Lake creek was the subject of the study. The creek falls under the stewardship of the Island Waters Fly Fishers – one of the local groups that have signed on to help NALT with research. Additional streams covered by the fly fishers include a Millstone River creek and some boundary areas.
Representing the fly fishers, Bernie Heinrichs has been doing licensed 'salvaging' in the creeks each fall for the past six years, rescuing small native fish from the isolated pools during the dry season and relocating them into the lake before the pools dry up.
"I'm a fisherman, I like to promote [fish] and get more fishing," he explained. "In 2007, Island Waters Fly Fishers volunteers … helped build the [Bowen Park bypass channel]. The reason we built it was so coho could go around the waterfalls that's in there."
Last week's outing was different from others, with Brooymans and Clark tagging along to record data as Heinrichs performed his regular salvage operations.
The data collected includes the species caught, measurements, depth of the pools, composition of the ground, oxygen level of the water and the specific coordinates, so the researchers can come back without Heinrichs during future expeditions. For the study, researchers will take data from each creek once per season throughout the year.
"There's a lot of variability with how much water is in the streams in certain seasons," Clark said, pointing to the dry stream bed with intermittent pools throughout. "Fish can obviously only live in places where there's water, as you can see, this is a good example. There's a lot more fish habitat in this stream during the winter ... So the idea is we're going to investigate their presence or absence."
To trap the fish, Heinrichs and the researchers use Gee's minnow traps, which are small metal cages with a hole in the side that the fish swim into. While the fish, theoretically, can swim out, many of them get confused and remain inside the cage by the time they're pulled out, which is within a day. For bait, Heinrichs has been using salmon eggs, but the bait can vary. At Cat Creek, Brooymans said researchers have been using canned salmon.
The study uses the same techniques and tools as Heinrichs; the main difference is in the objective of collecting the data rather than relocating the fish.
"Are there fish there or not, how many fish, or how healthy are the fish, or any of those other questions you might ask," Brooymans said. "We're just looking at 'are there fish there or not?' and that will give us a starting point to ask deeper questions."
The trip was fruitful, as a single cutthroat was pulled up from one of the five traps, among other fish, including a stickleback, sculpin, coho salmon and even a lone crayfish. The results were no surprise to Heinrichs, who reported finding a greater number of cutthroat in each of the traps two weeks earlier.
"Bernie has a lot of knowledge about what's been here over the years, a lot of the streams we're doing don't have that so in this case we're just trying to work off his knowledge and that's helpful for us," Clark said. "Not everywhere is going to be like that for us."
To volunteer for the project, those interested are asked to e-mail Brooymans at stewardship@nalt.bc.ca. The results are expected to be available on NALT's website, starting later this fall at http://nalt.bc.ca.
