a fish story from the yamhill river

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Photo Submitted ## Oregon State University graduate Andrew Chione, Steward of the Native Fish Society River in the Yamhill Watershed, holds a coho salmon carcass found in the Upper North Yamhill River.

Guest Writer Luc Westphal is executive director of the non-profit Greater Yamhill Watershed Council, where he joined staff in 2012. He works with local stakeholders to develop projects and forge partnerships for land, water and fish and wildlife habitats. wildlife in the Yamhill and Chehalem valleys. He was assisted in the development of today’s kit by Jim LeTourneux, an experienced collaborator in housing projects. A fourth-generation Oregonian, LeTourneux owns and operates the 460-acre Tripletree Timber operations north of Sheridan, at the upper end of the Gopher Valley.

What lies beneath the roaring currents of the Yamhill River and its tributaries might surprise you.

These local waterways teem with cold-water anadromous fish – thousands of juvenile salmon, trout and lamprey awaiting an instinctive call to swim 270 miles out to sea. After years of wandering the Pacific, they will once again be invited to return home to lay their eggs in the home waters of the Yamhill watershed and ultimately contribute their own bodies to sustaining this life cycle. aquatic.

The local shining star among these is the coho salmon. Coho are the most abundant ocean fish in our watershed, with over 250 miles of waterways designated for their habitat.

You are likely to find coho in the majority of the named tributaries of the Yamhill watershed, and even among the smaller ditches and canals. To better understand these distributions, Greater Yamhill Watershed Council staff and volunteers spent 10 years documenting sightings of coho spawning via GPS and identified many miles of waterways that were previously undesignated. as coho habitat.

Currently, the Upper Willamette Coho is considered a non-native but naturalized fish species, as seasonal conditions at Willamette Falls are believed to have historically prevented migration from spawning grounds prior to the installation of a fish ladder in the 1880s.

Coho hatchery stocking programs ran from 1954 until the 1980s, as the population was not expected to survive on its own. These planted stocks have somehow persisted over time and mixed with the wild population, creating a genetically unique naturalized superior Willamette coho.

In fact, this coho population has exploded over the past decade, with more than 20,000 coho roaming past Willamette Falls over several years. Studies have shown that the Yamhill watershed is one of the largest producers of this race and can accommodate over 45% of all Upper Willamette Coho that returns each year.

The underdog of the Yamhill watershed is a small but resilient population of Upper-Willamette winter rainbow trout. Studies have shown that the Yamhill River is the largest winter producer of rainbow trout from the Coast Range tributaries that drain into the Willamette River.

This species is considered native and has been listed as threatened under the Endangered Species Act since 1999. In 2017, a historic low return of 822 passed Willamette Falls, so its long-term survival remains uncertain.

As an ESA-listed species, more funding opportunities are available for projects to improve its habitat. These funds allow local landowners to cost-share with conservation organizations on voluntary projects that improve fish habitat, such as replacing failing culverts that impede rainbow trout migration.

Last but not least is the most mysterious of our local ocean fish, the Pacific lamprey.

Often referred to as an eel, the Pacific lamprey is a native parasitic jawless fish. Studies have shown that the Yamhill watershed is a major producer of Pacific lamprey in upper Willamette.

Until recently, little was known about their distribution in the Yamhill watershed.

To find out more, watershed council staff and volunteers collected environmental DNA samples from local waterways. This indicated that the Pacific lamprey was widely distributed in the watershed, inhabiting most major tributaries and even some small unnamed drainages.

Water quality is a priority factor for the health of local fish populations. One of the most important ways to improve water quality is to establish a buffer strip of native plants along streams, to provide shade over the stream and filter pollutants.

It is common to hear about the need for such vegetation buffers for waterways.

However, their size and composition may depend on your water quality goal. For example, one study showed that a pad width of 15 meters, or about 50 feet, reduced harmful toxins 2.5 times more than an 8 meter pad, or about 26 feet.

These 15 meter riparian buffers also provide higher levels of dissolved oxygen and organic carbon to streams. Depending on the watercourse and adjacent land use, the vegetation composition will vary, but generally includes a healthy mix of shrubs, grasses and trees.

Although the Yamhill watershed does not have large migration-limiting dams, as many other rivers do, studies have shown that failing culverts prevent fish migration to over 100 miles of riverine habitat. During low summer flows, juvenile fish are trapped at the downstream end of perched culverts, unable to jump the outlet to access the cooler, better waters above.

Some culverts blocking juvenile fish may still prove passable for adults, as they can make larger jumps. But the offspring of these fish will eventually feel the effects.

Most of the Yamhill watershed is privately owned, and thoughtful management of this land has a significant impact on the health of our waterways.

If you have a waterway on your property and would like to find out more about funding or technical assistance for land management and watercourse habitat, please do not hesitate to contact the Greater Yamhill Watershed Council at 503-474-1047 or info@gywc.org, or visit www.gywc.org/fish.

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