Threats to Salmon Habitat


IRiver habitatntact freshwater and marine habitat are both vital to different salmon life stages. Some human activities on land, in freshwater, and the ocean, can degrade habitat that’s critically important for wild salmon health. Generally speaking, if certain activities occur in an unsustainable or destructive manner anywhere, they could affect salmon. It’s all connected.

Salmon obviously need freshwater during critical life stages. For example, gravel beds with clean, cool, oxygen-rich water are needed for eggs to hatch. However, humans manipulate river flows in many ways that can affect salmon, such as water withdrawal, storage, conveyance and diversion for hydropower and flood control. These activities have degraded and eliminated large areas that were once prime habitat for salmon. Such changes can fundamentally alter the ecology of freshwater systems, changing nutrient flow and food availability. Altering natural flows in rivers and streams can also directly affect salmon by increasing water temperatures which can cause fish stress, as well as impeding migration, spawning, feeding and rearing.

Watershed Watch has produced several publications on freshwater habitat protection that provide tools and information on how to better protect it. A short comment on British Columbia’s new Water Sustainability Act provides an overview of where policy is going in B.C. and highlights the positive and negative aspects of legislation being developed to improve B.C.’s outdated water laws. We also sponsored a Simon Fraser University dialogue on Building a Vision for Green Energy in British Columbia that examined the prospect of hydro power development in B.C., including run-of-river projects and their potential negative effects, along with strategic solutions for the future. See our hydro power page for more information.

Riparian habitat refers to land that is adjacent to freshwater. When healthy, these swaths of land help keep water courses functioning properly. For example, heavily forested riparian areas can help shield streams from the sun, helping to maintain cool water for salmon to migrate and thrive. Intact riparian zones can also act as filters, to reduce pollutants from reaching streams and lakes. Plant communities also stabilize the soil with their roots and prevent too much sediment from entering the water. When riparian areas are degraded by logging, urbanization and other activities, freshwater systems nearby can suffer, along with salmon and other parts of the ecosystem.

Salmon lay their eggs in gravel and depend on productive gravel beds for food, such as insects. The natural ebb and flow of gravel down rivers is also an integral part of these aquatic systems, but can be threatened by gravel mining operations.

Wetlands—like marshes—are critical habitat for fish and also provide important ecosystem function such as water filtration. They’re also biologically diverse but are at risk from encroaching urbanization, commercial and industrial development and climate change. Wetlands are among the most endangered habitats in the world. Some useful tools to protect wetlands in B.C. are provided by the Wetlands Stewardship Partnership.

Colony FarmWe work with the Kwikwetlem First Nation in their traditional territory to support their desires to protect habitat and salmon rivers for future generations. Urbanization is a long-standing issue in their territory and Watershed Watch continues to support habitat enhancement and restoration, particularly along the Coquitlam River adjacent to Colony Farm. We are currently working with Kwikwetlem First Nation on a riparian planting project to increase native plant species, remove non-native species and improve the overall quality of the riparian habitat in the Coquitlam watershed.

Lakes and rivers are critical freshwater habitats for salmon migration, spawning and rearing. Everyone knows that all life needs clean freshwater, but many activities threaten its quality. Chemical pollution of water is common and occurs at many scales, from a small oil leak to large scale direct discharges from pulp and paper plants. Organic pollution, including run-off from livestock fields and sewage treatment plants can also pollute water by unnaturally elevating nutrient levels. Once in the waterway, pollutants can harm insects and other invertebrates—the primary food source for fish. Being conscious of your activities and vigilant of others’ can help reduce the amount of pollutants that reach lakes and rivers. Coastal marine areas provide habitat for rearing, migrating and resident salmonids. These areas can also be affected by industrial pollution and destructive activities such as aquaculture.

Fraser Basin LiveMapYou can learn more about salmon and water issues using Watershed Watch’s Fraser Basin LiveMap: An Interactive Salmon and Water Atlas. This web-based tool allows users to explore Fraser waterways and salmon populations, the threats they face, and their current status and future prospects.  The LiveMap includes official government data sets on historic water flows, salmon returns, water temperature, and other important factors that affect the aquatic ecosystems that make up the Fraser River watershed.