PRIEST RIVER — Not all rivers are created equal, according to the Idaho Department of Fish and Game.

Some, like the St. Joe, feature great habitat and reliably cold water, resulting in robust cold-water fish populations, such as westslope cutthroat and bull trout.

Others, like the Priest River, are not so fortunate, said T.J. Ross, an IDFG communications manager.

For decades, Priest River has suffered from overly warm water temperatures during the summer months. Cold water fish and warm water don’t mix well, and that reality came to a head in July 2021 with an unprecedented fish kill, Ross said.

Citizens, along with many organizations, are becoming more aware of the plight of Priest River, and they are beginning to organize. Efforts include the Priest River Watershed Group, which held its first meeting on Dec. 7.

IDFG, the Kalispel Tribe of Indians, Trout Unlimited and local residents are among those working to restore Priest River and enhance its fisheries to ensure it can be enjoyed by future generations in perpetuity, Ross said.

The effort gained momentum in the past year after the river warmed to over 70 degrees for an extended period in July, leading to a kill in which hundreds of fish died.

“The fish kill has been a catalyst of some really great things over the past year,” said Jon Quinn-Hurst, who has lived on the river with his family since 2007. “People are becoming more aware of the health of the river and are exploring options to help Priest River and the fish that call it home.”

Rob Ryan, IDFG regional fisheries biologist, said the kill was not a surprise, relative to this river. Trout are cold water fish and the Priest River is warmer than many of the state's rivers.

"It's no surprise that they got trapped in a hot water spot that they might not otherwise be in and that led to a fish kill," Ryan said.

Ryan said Priest River warmed up to more than 70 degrees in late August last year — "pretty warm" for trout, a cold water fish that relies on "nice cold water." However, water coming out of the nearby Big Creek measured at 56 in that same timeframe, which makes a big difference for trout, he said.

"Fish can withstand short-term temperature changes, even 70 degrees and beyond, but it's those extended long-term water temperatures that are elevated that really make it challenging to support fish populations in a place like the Priest River."

The fish population in the river, relative to similarly sized streams and rivers, are much lower. In comparison, the lowest stretch of the Coeur d'Alene River has probably 30 times the number of westslope cutthroat trout than Priest, Ryan said.

Priest River is fed by water from the surface of Priest Lake, which warms during the summer, so it has likely always been warmer than other regional rivers. However, operations of Outlet Dam at the south end of Priest Lake along with warming trends in climate have likely exacerbated the issue. Thankfully, opportunity to improve temperature, habitat and the fish community the river supports may exist.

“Trout are cold water fish, and the Priest River is too warm.” Ryan said. “Temperatures in the 50– to 60-degree Fahrenheit range are great for trout. When temperatures exceed 70 degrees, trout start to get stressed and potentially die because of warm water temperatures, especially when the warm temperatures are prolonged.”

Quinn-Hurst said he can remember a more robust fishery on the river back in the 1980s. Cutthroat, bull trout, brown trout and others — the angler said he has seen the numbers of all of the fish decline every year.

"Especially in the last 10 years because of the hotter summers and … 2015-2021 were what I call the killer summers, especially in 2021 in July, that first weekend in July, that fish kill was tremendous and it was heartbreaking to see hundreds of fish. The mortality was heartbreaking."

Among those working to protect the river and restore the fishery is the Kalispel Tribe, looking at cutthroat population and the overall habitat in both the main branch and tributaries of the river.

"The Priest River has always been really important to the tribe," Berntsen said. "It's got all the ingredients of being a really good trout fishery, it could have a real economic boon to the area. [It's] got the ingredients and I think it's just got a lot of potential."

Tribal elder Francis Cullooyah told Fish & Game officials in a video that he knows the river as something that is more or less a blessing the Kalispel.

"I stand here today and say this is my problem because I am a Kalispel," Cullooyah said in the video. "This is my aboriginal land, this is my aboriginal waterway. My heart tells me that something is happening, something is moving, something is going to happen to better our waters."

Information: idfg.idaho.gov/priest-river