Did you know that everyone lives in a watershed? If you live, work, and play in Washington County, you are part of the Tualatin River watershed! We share this watershed with an amazing array of wildlife species, including some reel-y cool fish. Fish require cool, clean water, so their presence (or absence) can tell us a lot about water quality and habitat conditions. We want to make sure that their habitats are protected and thriving.
What do fish need to stay happy and healthy?
Our Tualatin River watershed is home to many different fish species, each with their own life cycle and role in the ecosystem. However, they all share the same need for specific habitat conditions:

- Clean Water – Fish need water that is free of pollutantsPollutants A substance that has negative effects on the environment.. Polluted waters can increase algae and plant growth, decreasing the oxygen in the water that fish need to survive. Harmful nutrients from dog waste, fertilizers, and other sources can enter streams, impacting water quality. Pesticides and heavy metals can also wash into streams limiting the fish’s ability to smell to find food and detect potential predators.
- Cold Water – Fish thrive in water that is generally 65 degrees and below. Water temperature effects a fish’s ability to find and eat food, breathe, grow, and spawn.
- Habitat ConnectivityHabitat Connectivity The degree to which separate patches of habitat are connected. – Fish, and other aquatic life, need to move throughout different aquatic habitats to complete their life cycle or locate food and shelter. Barriers, like dams and undersized culverts (pipes that route streams under roadways), restrict access to important habitats.
- Log jams and woody debris– Log jams and woody debris help interrupt the downstream flow of water in a river or stream. Nutrients that normally travel quickly downstream, get trapped in pool areas creating more macroinvertebrates for fish to eat. These pools also allow fish to hide from prey and conserve energy.
What fish live in the Tualatin River Watershed?
Let’s learn about some of the fish species who call the Tualatin River watershed their home.

- Trout – There are many trout species living in freshwater streams, rivers, and lakes, including rainbow, redband, cutthroat, and steelhead. Some species are anadromous (uh-na-druh-muhs), meaning they spend part of their lifecycle in the ocean and part in freshwater, while others spend their lives entirely in freshwater.
- Salmon – Chinook and coho salmon are anadromous. Juvenile salmon will stay in freshwater for the first few months to couple of years of their lives. They will then migrate to the Pacific Ocean where they will eat and grow to an adult size. When ready, they migrate back to the streams where they were born to spawn and complete their lifecycle. Salmon have cultural significance for many Native American Tribes contributing to tribal religion, culture, and physical sustenance.
- Lamprey – Pacific lamprey are anadromous and belong to a family of eel-like fish. They don’t have scales and they have cartilage instead of bones. Lamprey have a jawless sucking mouth with several teeth that they use to attach to rocks and prey. Pacific lamprey have cultural significance for many Native American Tribes in Oregon. Their populations are declining due to various threats to their environment.
What can you do to help?

- Plant native trees and shrubs along waterways – Trees and shrubs provide shade to keep water temperatures cooler. The roots help prevent soil erosion and absorb excess nutrients that run off of lawns and agricultural fields.
- Reduce Pollution – Any pollutant can easily wash into a waterway. Remember to put trash in proper bins, pick up animal waste, and reduce chemical and pesticide use in your yard.
- Follow Water Recreation Guidelines – Water recreation equipment can transport invasive species. Make sure to rinse off your boat, kayak, paddleboard, and other water equipment after use. Drain any water and remove plants, animals, and mud.
Learn about our Habitat Conservation Program!