Daily monitoring of Methow valley waterways keeps track of temperatures
By Ann McCreary
With water temperatures in Methow Valley streams and rivers warming to levels that are harmful for fish, local biologists are monitoring conditions to determine if restrictions on fishing may be needed.
“We’ve narrowly avoided implementing a hoot-owl fishery,” said Ryan Fortier, district fisheries biologist for Washington Department of Fish and Wildlife (WDFW) in Okanogan County.
“When we see water temperatures approaching 65 degrees we start monitoring daily,” Fortier said. “We have monitored pretty regularly from the end of June.”
A “hoot-owl” restriction means that fishing is not allowed from early afternoon until midnight, Fortier said.
Salmon and trout need cool water as juveniles and adults to grow and reproduce. Extended bouts of very hot, dry weather this summer — with more projected in the next week — have caused water levels to fall to record seasonal lows and temperatures to rise in rivers and streams throughout the Northwest.
WDFW has closed or restricted fishing on more than 30 rivers throughout Washington to help protect fish in areas where drought conditions have reduced flows and increased water temperatures.
In north central Washington, sections of the Wenatchee, Icicle, Okanogan and Similkameen rivers have been closed, as well as Lake Wenatchee.
Rivers and streams were at a deficit to begin with due to the low winter snowpack, and prolonged heat waves early in the summer exacerbated conditions.
“It’s not necessarily the daytime highs that drive how much water temperatures will increase, it’s the nighttime temperatures,” Fortier said.
“A risky week is when we see overnight lows in the 60s, like it will be the first week of August,” Fortier said.
When water temperatures hit about 70 degrees, the conditions become dire for salmon and trout, Fortier said. “It increases the stress levels and all the things that go with that. “
Fish become unwilling to enter streams to spawn, they become lethargic and are more susceptible to disease. Some fish may die before being able to reproduce, Fortier said.
Already under physiological stress from the water conditions, fish may need added protection through restrictions in recreational fishing, Fortier said. Injuries and exhaustion that may occur when fish are caught and released can be fatal to fish that are already compromised.
Local fishing guide Kevin van Bueren, owner of North Cascades Fly Fishing, said this is one of the lowest and warmest water years he has seen in his 25 years of fishing in the Methow Valley.
“The water right now is higher than the lowest we see it, we just don’t see it [this low] on this calendar date,” van Bueren said. “These are like Labor Day lows.”
Van Bueren checks water temperatures three times a day while fishing and texts the information to WDFW. “If we see 65 degrees, that is going to stress the trout,” van Bueren said. “One time I pulled out [of the river] at Carlton and measured 66 degrees at 1 p.m. Generally, I’ve been measuring about 62 degrees.”
Some morning water temperatures have been as low as 52 degrees. “I think that’s great,” van Bueren said.
To monitor water temperatures, Fortier said he checks the Methow River in Carlton “where I know water temperatures will be warmer. I’ve seen temperatures in the upper 60s, but they haven’t been sustained.”
Van Bueren suggests fishermen adapt to the conditions by fishing in the mornings and fishing higher up in the watershed. He also advises fishing in a way that doesn’t cause unnecessary stress for fish.
“If you’re playing a big fish, keep him in the water and handle it appropriately,” he said.
A study released earlier this month by the Washington-based Wild Fish Conservancy analyzed seven-day average temperatures (from June 29 – July 5) in 54 salmon and trout-bearing rivers and streams in Washington, Oregon and California.
The study found that water temperatures in those waterways “exceeded thresholds which result in biological stress, indirect mortality and reduced spawning success.” The study reported “lethal” conditions in 39 of the rivers and streams that were evaluated.
The Wild Fish Conservancy, along with six other fish conservation and recreational fishing organizations, sent a written request to Northwest governors and wildlife officials urging states to close all river reaches to fishing, both recreational and commercial, if water temperatures exceed 64.4 degrees.
“These extreme conditions put a lot of pressure on our region’s threatened and endangered wild salmon and steelhead,” said Kurt Beardslee, executive director of Wild Fish Conservancy.
“With substantial losses of rearing juvenile salmon and resident fish expected to occur this season from high water temperatures and low flows in Pacific Northwest rivers and streams, it is crucial that fisheries managers insure that the stressed wild salmon and steelhead returning to the region have the greatest opportunity of passing unimpaired to their spawning habitats,” Beardslee said.
The Methow Valley watershed is home to federally protected species including bull trout, steelhead and spring Chinook.
Spring Chinook are currently in the watershed and are holding in deeper pools in rivers and streams, waiting to begin spawning in early August, Fortier said. Steelhead will return in the fall and bull trout, which remain in the watershed, have begun their migration toward spawning grounds in upper reaches and tributaries.
As the water levels fall, biologists will keep an eye on areas of the Methow, Chewuch and Twisp rivers that naturally go dry each year. Bull trout in particular, which spawn in October, can become isolated in pools surrounded by dry riverbed, and may need to be rescued, Fortier said.
Biologists are also making an effort to remove the many small rock dams in rivers and streams, usually created by people to capture water for swimming holes along riverbanks. Biologists have placed signs in campgrounds and along rivers urging people not to construct the dams.
Although they may be only a few inches high, the dams can create barriers that stop fish from migrating to spawn during low water, because there isn’t enough water for the fish to swim or leap over or around them, Fortier said.
“It seems like a goofy thing, but it’s critical,” he said.
The problems associated with low water levels and warmer-than-normal temperatures won’t be helped by a return to very hot, dry conditions projected for the region. The National Weather Service forecasts highs in the upper 90s with nighttime lows ranging from 59-62 degrees for the Methow Valley through Monday.
By the third week of August, when days become shorter and nights are cooler, concerns about water temperature will likely decrease, van Bueren predicted. Unless there is some precipitation, however, low water levels will remain a concern for fish.
“Tell everyone to do a rain dance,” he advised.