The new study has further cause for alarm for the steep decline of Steelhead populations in British Columbia. In fact, they argue that existing data could be masking major declines in these avian populations. Steelhead, or Oncorhynchus mykiss, are anadromous Rainbow trout. They are a keystone species in the province’s aquatic ecosystems and underpin $144 million in recreational fisheries. Every year, 21,000 anglers travel to British Columbia’s rivers to pursue these fish, pumping an estimated $50 million into the local economy. Here’s the good news. The study paints a picture of population recovery after decades of decline, thanks to remarkable conservation efforts.
In some rivers, steelhead naturally aggregate in particular river features, like riffles or pools, making them even more attractive targets to anglers. Sadly, in recent decades, Steelhead fisheries have been hit hard by the impacts of climate change and habitat destruction. The North Thompson River Steelhead population, once highly valued for its history and cultural importance, has drastically decreased. Consequently, the region’s recreational Steelhead fisheries have been nearly closed since 2018.
Conservation Concerns for Steelhead
Sharp declines in Steelhead populations has sparked intense conservation advocacy and lawsuits among environmentalists and fisheries managers. Despite British Columbia having over 400 Steelhead-bearing streams, only a handful of these watersheds are consistently monitored. Without additional population oversight, these alarming declines will continue to be underreported. Recent catch-per-unit-effort data may not reflect the true state of Steelhead stocks.
Julie Charbonneau, one of the lead researchers on the study. Her bottom line is that catch rates are dangerous to use when making population health assumptions based on individual catch rate.
“Our results suggest that individual catch rate may not be a reliable indicator of changes in steelhead populations.” – Julie Charbonneau
This statement underscores the need for more comprehensive monitoring efforts to understand the complexities of Steelhead populations across the province.
The Impact of Hyperstability
The new study is also among the first to identify hyperstability in inland recreational fisheries. This phenomenon, known as Holling’s type III functional response, happens when catch rates are still high even as fish populations are declining in reality. Consequently, anglers can see redd densities for certain stocks that appear flush with pre-warming conditions when large declines are happening out of sight.
Unfortunately, perceptions of abundance are not always what they seem, cautions Katrina Connors, another researcher on the project.
“Catching more [fish] does not necessarily indicate high levels of abundance.” – Katrina Connors
From this analysis, it appears that hyperstability may be insidious throughout British Columbia. This high prevalence asks important questions of what we are doing in terms of management and conservation.
Economic and Social Significance
Steelhead fishing has deep social and economic value to communities across British Columbia. The billions created by recreational fishing activities boost local economies and support half a million jobs in the process.
The decline of Steelhead populations poses a dual threat. It jeopardizes both the ecological balance and the economic fabric of communities that rely on this vital resource. The concerns raised by the study call for immediate action to improve monitoring and conservation efforts to ensure the sustainability of Steelhead populations.
Julie Charbonneau further elaborates on the implications of their findings:
“If hyperstability is as prevalent across the province as suggested by this analysis, then the observed declines in catch rates could be associated with substantial declines in true abundance.” – Julie Charbonneau