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- Featured Article
- Tip of the Month
- Green Space
- Did You Know?
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- Photo of the Month
- Fly of the Month
- Courses and Seminars
Green Space
By Katrina Assonitis
Concerns regarding the fate of Pacific salmon have been mounting over the last decade with over-fishing and habitat destruction generally being cited as the primary causes of population-level declines. While the impacts of unsustainable fishing practices and urban development cannot be understated, relatively little attention to-date has focused on the impacts of groundwater withdrawals on salmon populations.
Groundwater is vital to salmon during the freshwater phases of their lifecycle. Groundwater influences salmon distribution, reproductive success, biomass and productivity, behaviour and movement. The role of groundwater is particularly important in the winter and summer months when extreme temperatures threaten the survival of resident salmonids. Groundwater temperatures are generally close to the average annual temperature and are thus stable relative to surface water. In the winter months, warmer groundwater temperatures help to delay and even prevent ice formation providing valuable ice-free spawning and overwintering habitat. In the summer months, cool groundwater inflows moderate stream temperatures providing critical thermal refugia for adults and fry exposed to potentially lethal temperatures.
Unfortunately, in many areas throughout the province the groundwater needs of salmon are at odds with the water needs of humans who extract groundwater for housing developments, agriculture, recreational activities and commercial developments. British Columbia lags behind other North American jurisdictions in its regulation of groundwater extraction with BC landowners currently being able to extract water from the ground without any consideration of the effect of groundwater extraction on surface water flows or fish habitat. Provincial officials have no way of assessing the full extent of groundwater use, let alone mitigate the environmental impacts, generating some concern regarding the implications of groundwater extraction on endangered salmonids, such as Interior Fraser Coho.
The Fraser Salmon and Watersheds Program is helping to support a number of research projects investigating the importance of groundwater to salmon. This type of research could lead to major changes in the way groundwater is managed by forcing resource managers to expressly consider groundwater upwelling habitats for threatened or endangered salmonids. To read more about our salmon-groundwater interaction projects, as well as a host of other studies funded by the Fraser Salmon and Watersheds Program, please visit www.thinksalmon.com.