Chinook of the Tatalu
A fall update from the BC Conservation Science team
By Lanie Fung, Conservation Biologist
November 15, 2022
The Tatalu (Little Campbell) River is home to five species of Pacific Salmon, including the Chinook (Oncorhynchus tshawytscha). Boundary Bay Chinook Salmon, which include the Chinook that spawn in the Tatalu, are classified as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Current estimates are that fewer than 1000 mature wild fish remain (COSEWIC, 2020), but we will have a better estimate of this number as a result of research we are now conducting.
Chinook salmon populations have declined in recent decades for a variety of reasons, including their susceptibility to drought and extreme warm temperatures. In one British Columbia river this fall, the extended summer drought conditions led to the death of thousands of early spawning Pink Salmon (CBC, 2022). In the Tatalu, the salmon returned much later than expected, probably due to low water levels and warm temperatures. Though variability in salmon rivers is natural, climate change is amplifying these existing stressors. More frequent extreme heat events mean that the freshwater streams juvenile chinook live in get warmer and become shallower than they have been historically, making it more difficult—and sometimes impossible—for them to survive. Salmon also require relatively high levels of dissolved oxygen, but warmer water is able to hold less dissolved oxygen than cooler water.
One action the Conservation Science Team takes to improve stream conditions for juvenile salmon is restoring important streamside vegetation that helps shade the river and keep it cool. This vegetation also prevents erosion, which helps the river stay clear of fine sediment, which degrades spawning habitat.
You can support our work through a donation towards conservation of the Little Campbell River. Conserving and restoring natural areas is necessary both for protecting important species like salmon and also the people and biodiversity that share these unique ecosystems!