Alberta’s Bull Trout Need Our Respect — and Our Help
BY JENNIFER EARLE
Bull trout seem to be the Rodney Dangerfield of fish — they get no respect. They are the official provincial fish of Alberta, yet this distinction hasn’t served them particularly well. They are listed as Threatened under both provincial and federal legislation. So how did we get here?
Bull trout are native to western North America and they are the only native char to historically occupy all the drainages of Alberta’s Eastern Slopes.1 In Alberta, they can grow to over
80 cm in length and 8 kg in weight — an impressive feat considering they live in cold northern waters.
One of my first encounters with bull trout was in the mid-1990s in the Smoky River watershed near Grande Cache. I’m a sucker for mountains and the combination of tenacious fish and jaw-dropping scenery drew me to this part of Alberta. I was working for an environmental consulting company at the time and bull trout were the primary species we encountered in most streams. We caught bull trout in spots where no fish had a right to be — above waterfalls, in turbulent alpine and subalpine waters, and in headwater streams where you could literally watch the stream’s journey begin as a spring bubbling straight out of the ground. These are beautiful places on warm August days, but harsh as heck for most of the year. In many places, bull trout were the only species we caught and while they may not be the showiest of fish, they get the job done with a quiet competence and perfect design. I find that both fascinating and admirable.
I think bull trout are the most undervalued and misunderstood native fish in the province. If you heard your grandfather say, “We should kill them, they eat more valuable fish,” you are not alone. Sadly, these attitudes originated over a hundred years ago and persist, in some circles, to this day. If you are not already a supporter, I hope to convince you that bull trout are a fish that deserve to be valued, protected, and restored to some degree of past exuberance.
Colpitts2 provides a historical perspective of conservation policies in the early 20th century, particularly in relation to bull trout. These policies largely favoured the introduction, through stocking, of non-native trout species that were considered more desirable because they were supposedly more “handsome” and provided greater sport for anglers. These policies increased disdain for bull trout and also encouraged attempts to eradicate the species.
Unfortunately for the bull trout, they are readily caught by anglers because they are opportunistic feeders. They also have a late age at maturity (5–7 years), which means they are vulnerable to angling long before they can spawn. Although catch-and-release fishing has been mandatory in Alberta for this species since 1995, studies have shown that where angling effort or hooking mortality are high enough, even zero-harvest policies may not be enough to allow population recovery.3
Bull trout aren’t immune from other risks in the watershed either. Water quality (e.g., sediment and phosphorus inputs) and barriers to fish passage (e.g., dams and culverts) are the most common key threats limiting bull trout populations.4 As an example, road density, which leads to higher habitat fragmentation, sedimentation, and increased public access, is frequently correlated with reduced bull trout occurrence.5
To understand the impacts of habitat fragmentation, it helps to know that bull trout have three main life history types: stream resident (residing within the tributaries in which they were reared), fluvial (spawning in tributaries but residing in larger rivers), and adfluvial (spawning in tributaries but residing in lakes or reservoirs). The migratory nature of these fish demonstrates the diversity of habitat types, scale of movement, and connectivity that is required to carry out their life cycle.
Some of the reasons I find bull trout so interesting also explain why they are in trouble. Remember when I mentioned that some people believe bull trout are not a handsome fish? I disagree but, as they say, “beauty is in the eye of the beholder.” As part of salmonid identification testing we did in 2005–2006, bull trout was the species most often incorrectly identified by anglers — 54% of the time.6 This surprised me, since bull trout are characterized not by the presence of consistent distinctive features, but rather by a lack thereof. For example, they lack the black spots or dark markings on the dorsal fin and body found on other char and trout species, and lack the red throat slash of the cutthroat trout. It appears that this lack of distinctive features confuses people into thinking the bull trout looks a little bit like everything else. This makes it more susceptible to unintentional harvest as it may be mistaken for a fish that can be legally harvested.
One of the most common misconceptions I hear about bull trout is that they eat more “valuable” fish, and will cause the complete demise of our native westslope cutthroat trout, another species at risk in the province. However, Nelson and Paetz7 suggest that both bull and cutthroat trout used the same routes to recolonize Alberta’s waters from their glacial refugia in the last Ice Age. I like to picture them fin to fin, boldly swimming forward to this new and exciting landscape. Flights of fantasy aside, this means that both species — and indeed many others — have coexisted for a long time. Getting eaten by each other has never been cited as a threat to the recovery of either species. In fact, apart from hybridization, cutthroat trout are faced with the same major threats as their long-ago travel partners.
Bull trout are opportunistic foragers. Juveniles commonly feed on aquatic insects, while adults will eat fish as well as benthic invertebrates. Their relatively large mouth enables them to consume prey up to 50% of their own length. In 2011, we did a netting survey in the Kananaskis Lakes and found that a large proportion of the adult bull trout were consuming a wide variety of invertebrate species. The number of bull trout that had evidence of fish remains in their stomachs was comparatively low. It was a fascinating exercise; a little gory, but it opened my eyes to the variety of diet and the ability of this fish to self-regulate by distributing the prey items across different taxa in the same lake.
This brings me to what prompted me to write this article in the first place. Did you know that our bull trout can live to a ripe old age? Previous data from Lower Kananaskis Lake’s adfluvial population revealed a substantial and continuous decline in bull trout numbers from 1954 to 1992. It was thought that the primary reason for this was overfishing8.
To support recovery efforts, studies were undertaken from 1991–20029 that involved marking bull trout with external numbered tags. Anglers continued to call us for years afterwards with reports of catching these tagged bull trout. We were able to look up the tag number and let them know when it had been tagged, how much the fish had grown, and its approximate age.
Several years ago, those calls stopped — until December 2019. An angler ice fishing on the lake caught a tagged fish and forwarded the information to us. I thought it had to be a mistake as it implied a fish much older than commonly reported for the species. While some reports suggest a maximum age for bull trout of 20 years (with a record of up to 24 years in British Columbia10), 10 to 13 years appears to be more common across their range. Based on previous tag returns we knew we had bull trout living in the lake for 16 to 20 years, but was an even more venerable specimen possible?
From our records, we know this fish was mature (i.e., in spawning condition) when first caught and tagged in 2000, so it was likely at least five years old at that time. Add the time until it was caught in 2019, and we have a fish that is at least 24 years old, perhaps older. To put that in perspective, this fish was probably hatched a few scant years after the back-to-back World Series wins of the Toronto Blue Jays (sympathies to present-day Jays fans).
What We Can Do To Help
There are a number of ways we can help alleviate threats and promote recovery for this species. You are doing one of them right now. By learning more about Alberta’s native trout, you can help spread the word and be bull trout boosters!
In the case of Lower Kananaskis Lake, changes to address overharvest, including closing the spawning tributary to angling and implementing mandatory catch-and-release fishing, made a substantial difference towards recovery of this population. As an angler, you can help by knowing your species so as to properly identify your catch, following safe handling and release practices (such as those outlined at keepemwet.org), and by avoiding targeting bull trout in watersheds where populations are at high risk.
As an individual, you may not think there is much you can do to address large landscape threats such as sedimentation and man-made barriers to fish passage. As part of a group, however, you can get involved in stewardship initiatives that help champion these issues and effect change at a local scale through volunteer projects. There are many worthwhile provincial and local watershed groups that would welcome your assistance.
I hope I have convinced you that native fish species such as bull trout have value. Their presence (or absence) tells us something about the health of our watersheds. Our native species are an important part of our heritage and fundamental to what makes Alberta’s natural resources unique. We may have a legal obligation to restore species at risk and maintain biodiversity, but I would argue we also have a moral one. Please give our bull trout the respect they deserve!
Jennifer Earle has spent a lifetime being fascinated by all manner of creatures living in and near water. She is a professional biologist and currently works as a Fisheries Biologist for Alberta Environment and Parks.
This article originally ran in Nature Alberta Magazine - Summer 2020, Volume 50 | Number 2
1 Post, J.R. and F.D. Johnston. 2002. Status of the Bull Trout (Salvelinus confluentus) in Alberta. Alberta Sustainable Resource Development, Fish and Wildlife Division and Alberta Conservation Association. Wildlife Status Report No. 39. Edmonton, AB.
2 Colpitts, G.W. 1997. Historical perspectives of Good vs. Evil: Stream eugenics and the plight of Alberta’s Bull trout: 1900-1930. In Friends of the Bull trout Conference Proceedings. Edited by W.C. Mackay, M.K. Brewin, and M. Monita. Bull trout Task Force (Alberta), c/o Trout Unlimited Canada, Calgary, AB. p. 31–36.
3 Post, J.R., C. Mushens, A. Paul and M. Sullivan. 2003. Assessment of alternative harvest regulations for sustaining recreational fisheries: Model development and application to Bull trout. North American Journal of Fisheries Management 23: 22-34.
4 Alberta Sustainable Resource Development (ASRD). 2012. Bull trout conservation management plan 2012-2017. Species at Risk Conservation Management Plan No. 8. Edmonton, Alberta. 90 pp.
5 COSEWIC. 2012. COSEWIC assessment and status report on the Bull trout Salvelinus confluentus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. iv + 103 pp.
6 Stelfox, J.D., and J.E. Earle. 2013. Salmonid misidentification by anglers. Unpublished report, Alberta Environment and Sustainable Resource Development, Fisheries Management Branch, Cochrane, Alberta.
7 Nelson, J.S. and M.J. Paetz. 1992. The Fishes of Alberta. The University of Alberta Press, Edmonton and the University of Calgary Press, Calgary.
8 Stelfox, J.D. 1997. Seasonal movements, growth, survival and population status of the adfluvial Bull trout population in Lower Kananaskis Lake, Alberta. In Friends of the Bull trout Conference Proceedings. Edited by W.C. Mackay, M.K. Brewin, and M. Monita. Bull trout Task Force (Alberta), c/o Trout Unlimited Canada, Calgary, AB. p. 309–316.
9 Johnston, F. D., Post, J.R., Mushens, C.J., Stelfox, J.D., Paul, A.J., and B. Lajeunesse. 2007. The demography of recovery of an overexploited bull trout, Salvelinus confluentus, population. Can. J. Fish. Aquat. Sci. 64:113-126.
10 McPhail, J.D. 2007. The Freshwater fishes of British Columbia. The University of Alberta Press, Edmonton, Alberta. 620 pp.
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