The long hot summer: Three ways for anglers to minimize their impact on steelhead

In California, Idaho, Oregon, Washington by steelheaders


 The long hot summer: Three ways for anglers to minimize their impact on steelhead

John McMillan

It may be universally said that low stream flows and hot water are bad for salmon and steelhead, which is why this year is strikingly painful to experience as angler and scientist. Unquestionably this is the driest early-summer I have experienced in my time on the planet. There have been similar summers though, and my memories of those summers shaped my understanding of when to fish, and when not to fish. To understand when it is time to sit along the river bank, or take a swim. To understand when it is a fair sport, rather than a game of shooting the proverbial fish in a barrel.
Hot summers like these provide an opportunity for anglers to learn about how to know when to fish and when not to. One such summer for me was 1987. It too was a long hot summer on my home river, the Washougal. Water temperatures peaked in the low- to mid-70°F’s nearly every afternoon and cooled only to mid-60°Fs at night. By early August the water was too warm for steelheading, at least if I wanted to release the fish and expect it to survive. I was a precocious 15-year old though and confident I could land a fish quickly enough that it would be fine. But in a morbid teenage way I also curious to see what the threshold was for steelhead.

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At 7:30pm I walked below my house and began fishing. Within half hour I hooked and landed a 10lb hen.  She fought poorly, like dragging in a wet towel. I had to spend nearly an hour trying to revive her. She was wild. I desperately wanted her to survive. For awhile I thought she would make it. She would balance and swim a few feet. Eventually however the only motion was the sporadic gasp of death, and her deep black eyes went lifeless. The last I recall seeing was her milky white side underwater as she drifted down a riffle and disappeared into the depths of the pool.

I took the water temperature before walking back to my house. It was 71°F. Much too warm for steelheading. I knew better. My dad had stopped fishing two weeks ago.

That was the first steelhead that I know I killed — other than for food — while fishing.

Since that day, I had two other experiences in warm water where fish died. As a result, for the past twenty five years I have stopped fishing once water temperatures reach 70°F at any point during the day.

Why 70°F? The first is because it seems like a logical cutoff point as an angler. We are fishing for cold water species, and 70°F seems to be the point at which wet wading becomes strangely uncomfortable for anglers accustomed to fishing cold steelhead and trout streams. Second, there is science indicating that catch-and-release mortality rates on steelhead increase once water temperatures start to exceed 70°F. For example, Taylor and Barnhart (1996: Mortality of caught and released summer steelhead) caught 126 steelhead on blue fox spinners in the Mad and N.F. Trinity Rivers, California. CnR mortality was less than 5% when water temperatures were below 64.4°F, which is fairly consistent with other studies on steelhead mortality that were also conducted in colder water temperatures. Mortality rate jumped to 22% for the 45 steelhead that were landed when temperatures were 70°F and higher. Similarly, but for Atlantic salmon, Wilkie et al. (1996: Physiology and Survival of Wild Atlantic Salmon Following Angling in Warm Summer Waters) documented a mortality rate of 40% once water temperatures exceeded 71.5°F.   Mortality rates as high and higher have been found in cutthroat and rainbow trout once water temperatures exceed 70°F.

  • Lesson #1: Avoid angling when temperatures are exceeding 70°F.


Steelhead tend to become lethargic when temperatures get really warm, so they are less likely to strike at a lure, fly or bait. Particularly so when stream flows are also very low. However, anglers and scientists have keenly noticed over the years that steelhead tend to congregate into cooler water areas to survive in places that would otherwise be unbearable. Such behavior is called behavioral thermoregulation. The animal is regulating its body temperature by seeking out and using a habitat with a different temperature. Metaphorically, the steelhead are not much different than the animals at the watering hole in the Serengeti. They are finding a way to survive in a watery desert.

While the behavior is completely natural, large congregations or schools of steelhead packed into small areas within a river — such as we commonly see in deep pools or near tributary mouths — are highly susceptible to persistent anglers. They have more energy because of the colder temperatures, and while they may indeed fight very hard after being hooked, it is important that we remember their bodies have already been under tremendous stress and will have to continue persisting through more stressful conditions. We as anglers must ask ourselves whether the elation derived from a few moments of hooking a fish is worth the imminent cost to the next generation of steelhead, which hopefully return during better conditions for summer angling.

  • Lesson #2: Do not fish for steelhead that are schooled up in cool water refugia to avoid otherwise highly stressful or lethal temperatures.

I understand that regulating ourselves now during these hard times will do nothing to alleviate the threat of warmer water temperatures. Fish will die this summer, regardless. It is that bad. And, an angler can rationalize, “I’m only catching one or two fish, what’s the harm?” All understandable points, but they do not necessarily relieve us of our responsibility as anglers to behave ethically during times when fish are vulnerable. Further, recall the nature of salmon and steelhead reproduction: only a few steelhead produce the vast majority of offspring in any given population in any given year. So it is not always about how many steelhead are caught and released, but whether it is one of those rare few fish that are the great producers?


That being said, there are still opportunities to fish for steelhead this summer. Not all streams or stream reaches are equally in the hot-zone for steelhead. Also, if you feel you cannot survive without angling, do so in the mornings and try to stop before noon. Some anglers suggest fishing evenings too. I would suggest this is a bad idea in areas where day-time temperatures are reaching and exceeding 70°F.   In afternoon or early evening the steelhead are still carrying the physiological stress of the day’s temperatures and temperatures at dusk are often only minimally cooler than those during the afternoon peaks. My suggestion is angler’s carry a thermometer and pay close attention to stream gages with temperature readings. That type of information will help you determine when to fish, and when not to fish.

  • Lesson #3: Fish in rivers and river reaches that are cooler, and limit fishing in warmer reaches to morning when steelhead are under less stress.

This summer is a great lesson, and contextually for this generation of young anglers, not unlike the summer in which the 10lb hen died behind my house. These types of hard times are when the true responsibility of the angler is measured. It is our conservation burden to bear, for better or us. It is during these times that steelhead need us more than we need them.

John McMillan – Steelhead Scientist Trout Unlimited