PUYALLUP (September 7, 2007) – As rivers and creeks warm during the summer, conditions can become unbearable for salmon. That’s why the Puyallup Tribe of Indians is monitoring water temperatures throughout the Puyallup River watershed to protect salmon.

This summer the tribe established an extensive network of more than 50 thermisters – thumb-sized devices that record water temperature at 30 minute increments. “Water temperature is an important part of ensuring strong salmon populations,” said Char Naylor, water quality manager for the Puyallup Tribe. “If the water is too warm for salmon, even just by a few degrees, it can be lethal.” Fatigue and disease are two conditions that have been connected to salmon deaths in warm creeks and rivers.


Chinook salmon and bull trout are especially affected by temperatures because they spend more time in freshwater as juveniles. Both are also listed as “threatened” under the federal Endangered Species Act. “Salmon and trout are especially vulnerable when they are young, it’s important that they have good conditions to thrive,” said Naylor.

“Warm water can be caused by a number of sources, such as low flows or a lack of trees along the bank of a creek,” said Naylor. A river’s physical structure can also affect water temperature. Restoring side-channels and connections to the floodplain is critical in lowering temperatures. This is especially true in the Puyallup watershed, where many of the streams and rivers are diked to prevent flooding.

“If we see a change in water temperature from year to year, we can find out what is causing it,” said Naylor.

High water temperatures can especially be problematic for bull trout in the Puyallup watershed, which spawn and rear for most of their lives in the river’s glacial-fed upper reaches. “When bull trout migrate down to the lower Puyallup, they can run into some pretty warm water, which can be a shock to their system,” said Naylor.

In addition to tracking temperatures throughout the watershed, the tribe is also building a heat source model for the Puyallup River. The model will predict the impact that actions along the river – such as development or logging – will have on water temperature. “With the model, we can look into the future to see how actions down the road will affect salmon,” said Naylor.

“To restore salmon in the Puyallup River, we need to ensure they have clean, cool water,” said Naylor. “If salmon have what they need, such access to the ocean, abundant spawning and rearing habitat and clean water, they will thrive.”

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For more information, contact: Char Naylor, water quality manager, Puyallup Tribe of Indians (253) 573-7851. Emmett O’Connell, South Sound information officer, NWIFC, (360) 528-4304, eoconnell@nwifc.org