Don Chapman, Idaho's respected fish scientist, is constantly thinking deeply, broadly and ahead • Idaho Capital Sun

Don Chapman and Bill Platts are Idahoans whose careers in science have built our shared understanding and caretaking of fish and rivers. Both men are now in their middle 90s. Don resides in McCall, Bill in Boise. Here I write about Don; Bill Platts will follow, in a month or so.

 In saluting these two men, I also salute their trade, and those who follow it: the close observation of salmon, trout and their waters. In classroom, field and well-rifled filing cabinets, scientists who could be their grandchildren now build from their work. Conversations with another such observer, Bert Bowler, spurred me in this respect among others.   

The knowledge and long experience of these two men also matters to a collective choice now before our state and region: Will we allow wild steelhead and salmon to disappear from Idaho and eastern Oregon, or change our course? Will we keep the Salmon River for tomorrow’s Idaho, or hand down, as our legacy, the Salmonless River? The extinction of Snake River salmon, which began with white settlement, is now in its endgame, in our time and before our eyes. Chapman and Platts offer evidence, and example, to we who will make the human part of the choice. Salmon will have a part too, and we can have faith the fish will do their part if we do ours.     

In 1969, Russ Thurow began studying fisheries science at the University of Wisconsin-Stevens Point. Prominent on his reading lists were the advanced research and analysis issuing from Don Chapman, at the University of Idaho. A couple years later, Don came to Wisconsin for a few days to present a seminar. “We were blown away by Dr. Chapman and his work. It became, when we grow up, we want to be just like Don Chapman.”  

Which, in a way, happened. Thurow came to Idaho and made his own lifetime career in trout and salmon science. He, and Don’s U of I students, became parts of the 1970s-80s influx of fish scientists into state, tribal and federal agencies Northwest-wide – and, a bit later, into profit and nonprofit enterprise. One braid in Chapman’s achievement is as catalyst over decades to more fully knit fish science and fish management. Much of the knit took the form of well-trained scientists.     

Every former student I reached recalls him with gratitude. Their voices grow bright. He was well-prepared, demanding, exceptionally intelligent, a professional example of hard work and clear thinking. In sum, an excellent teacher and inspiring mentor.    

In the field, Don taught the strenuous practices of fish research in rivers and streams. His students spent much time in wet suits, face down in waters, learning how to observe and measure fish populations, behaviors and what regulates those behaviors and outcomes in living rivers.

“He was a taskmaster,” Fred Everest recalls. “He worked our asses off. He was one of the best in the country, and I was all in.” Dr. Everest went on to U.S. Forest Service research stations in Oregon and Alaska, publishing some 100 reports and papers.  

In class, Don covered extensive ground, required deep reading and introduced advanced mathematics. Here is Richard Scully, of Lewiston, Idaho Fish and Game biologist, retired: “Don taught me population dynamics. It was intense. He was expert at math and statistics. Always straightforward, to the point. He also listened very closely; you could tell you had his full attention.”  

Greg Munther later became the Sawtooth National Recreation Area’s first fish biologist in 1974: “He challenged us all to think deeper, to put things together. And he gave me the tools with which to challenge my own thinking.”  

Steve Pettit, Idaho Fish and Game combat biologist, retired: “I took fisheries management from Don and enjoyed every second. He was a wonderful lecturer, a deep thinker, a real mentor. Also, he had so much practical field experience.”   

His students couldn’t miss Chapman’s high stature with his peers. Steve Pettit recalls a big meeting of fish managers and scientists at the Columbia Gorge Hotel in Hood River, in the 1970s. Some 300 people listened as Don Chapman warned about “scientific onanism” and how to avoid it. “The thrust was: Make sure you have your empirical results nailed before you say anything about your work. How he laid the subject out and examined it was masterly. He got a standing ovation; people were buzzing about it at dinner.”

An Idaho fish story

From 1964 to 1972, Don taught within, and led, the newly-formed Cooperative Fisheries Research Unit at the University of Idaho. Coop Units link agencies and institutions that have fish problems to solve or knowledge gaps to fill, with graduate students who do tailored research as part of their progress toward professional degrees. Senior scientists lead the Coop, teach students, guide research, and continue their own work. In eight-plus years, Don and his colleague Ted Bjornn built the Idaho Unit into one of the nation’s best. 

A half-century later, the Idaho Fish Coop Unit continues at Moscow, now merged with the Wildlife Unit. Courtney Conway, its current leader, told me fisheries graduate students now number two to three times those in Chapman’s years, half or more of them female. Its couple hundred students over six decades are generationally laced through the Idaho Fish and Game Department, other state fish agencies, federal and tribal agencies and businesses. Chapman laid its keel well and durably, 60 years ago. (See https://www.uidaho.edu/cnr/idaho-cooperative-fish-and-wildlife-research-unit.)

Westslope Cutthroat Trout, or WCTs, offer a good example of Chapman and the Idaho Fish Coop Unit at work.

“WCTs are the most catchable salmonid in the river,” Steve Pettit says. “They don’t develop wariness, and in granitic Idaho streams it can take them six years to mature, which is a long time to not get caught. So they’re very susceptible to angling pressure.”

In the 1950s and ‘60s, WCT decline became serious in many Idaho rivers, as roads were punched deeper into backcountry and fishing followed the roads. 

In Kelly Creek, in the North Fork of the Clearwater River, WCTs were getting scarce and much smaller. “In 1970 or so Don came up with an idea:  study if a non-consumptive fishery would work. What would happen if you changed the local regulations to catch-and-release for WCTs?” It was the first catch-and-release evaluation in Idaho. Idaho Fish and Game and the Idaho Coop Unit collaborated to secure federal funds. A year-plus into the research, Chapman hired Pettit for the extensive summer field work that Coop Unit grad student Kent Ball had begun. 

The results were compelling. WCT abundance in Kelly Creek increased three to sixfold after two years of catch-and-release, and 13-fold after five years. Fish size increased markedly. Fishermen who thought catching a WCT was likely to kill it even if released alive were shown wrong. In their fine paper on the wider WCT comeback in Idaho, Jerry Mallet and Russ Thurow write that the “Kelly Creek investigations were the first to confirm that catch-and-release was effective in increasing WCT abundance and size, while maintaining angler opportunities.” (Jerry Mallet and Russel F. Thurow, “Resurrecting an Idaho Icon: How Research and Management Reversed Declines of Native Westslope Cutthroat Trout, Fisheries, American Fisheries Society, 2001.  DOI:10.1002/fsh.10697.)  

These lessons were quickly applied to WCT management in other rivers, and to wild steelhead and other species.

“Catch-and-release regulations caught on fast, in Idaho, around us, and Canada,” Pettit says. “Don’s idea got a lot of that rolling.”  

A fish scientist in forward motion

Don’s own scientific work ranged widely over decades. He was research director for the Oregon Fish Commission before coming to Idaho. After Moscow came seven years with the U.N. Food and Agriculture Organization, leading fish stock and catch assessments on Lake Tanganyika, the Zambezi River, the Magdalena and Amazon Rivers, and other waters in South and Central America and Africa. This was science applied to help on-site managers and users monitor and sustainably exploit fisheries. 

Returning to Idaho in the late 1970s, Chapman began consulting for agencies, tribes and businesses, mainly in the Northwest, California, Montana and Alaska. He was an independent consultant for the U.S. Justice Department in the historic Boldt Two court proceedings, and a consultant to tribes on other cases. (Boldt One established tribal treaty rights to share equally in harvest. Boldt Two framed up the co-management to assure the equal share occurred.) He advised Idaho Fish and Game in harvest allocation, where advanced math is an essential language. For Northwest public utilities, Don developed estimates of pre-Caucasian Columbia and Snake River salmon and steelhead numbers and led status assessments of remaining populations. He served on the National Research Council’s salmon panel, convened after the Endangered Species Act listings of Columbia and Snake salmon in 1992-94.

Of his publications, I will pause on his 1966 synthesis, “Food and Space as Regulators of Salmonid Populations in Streams.” (D.W. Chapman, The American Naturalist, Vol. 100, No. 913, July-August 1966, pp. 345-57.) Here he seeks patterns across some 30 face-down-in-the-river research papers, including his own, to propose a conceptual theory of the factors that regulate trout and salmon populations in streams. Food and space are the main regulators, in site-distinctive, complex interactions.  

The paper quickly landed on fisheries’ reading lists — and is now a classic. What impresses this non-scientist is its brisk pulse, of science in forward motion. Reporting his own research, Don notes other findings that qualify or complicate his. He speculates (his word) toward pattern and theory across rivers and species, and formulates new lines of inquiry. The paper models the helix of close investigation and interpretive imagination that good science applies, in pursuit of what and why, information and meaning.     

The voice is unmistakably Don Chapman’s, calling himself, students and colleagues to move fish science forward. Today, much of the pattern-seeking, predictive work in fish science is expressed in advanced mathematics, an evolution Don was part of. But in this paper he works in words, which, with diligence, I can understand. 

‘I can no longer defend the dams’

In his unretiring retirement, Don became a public pivot in scientific consensus about the lower Snake River dams.  

Through the 1990s, he opposed their removal. He believed barging young ocean-bound salmon around dams, plus other adjustments, could sufficiently mitigate harm from the dam system. The case for dam removal he judged uncertain. And, he was expert in the harm from many cases of degraded natal habitat in Idaho and elsewhere, and from some ocean and in-river fisheries. For some of this time, Don was consulting for Northwest public utilities, which sought to minimize Endangered Species Act-driven changes at dams. Some former students and colleagues were uneasy, or upset, about his positions on dams while a utility contractor. Don was unapologetic. His uncertainty if the four dams had to go was publicly and politically influential.

Dave Burns publicly debated the subject with Don around 2000. Dave was a University of Idaho fisheries Ph.D. student just after Chapman departed Moscow, then a Payette National Forest fish biologist for 30 years, president of the Idaho Chapter and Western Division of the American Fisheries Society along the way – and, a McCall friend and fishing buddy of Don’s.

“We took opposite points of view in the debate,” he says. “But I think Don was starting to change his mind around then. He kept weighing the evidence. He always mulled ideas and talked ‘what ifs’ with colleagues.”

When Don did change his mind, in 2005, he went public to Rocky Barker, the inland West’s best and best-read salmon journalist.

“I had known Don, and reported his arguments, for 15 years. I called him ‘the voice of scientific uncertainty’ to my readers. Then he phoned me: ‘I can no longer defend the dams.’ It is one of the great stories of my career. It went all over, generated more stories and more debate — as Don knew it would, and wanted.”

Chapman’s main reasons for his change were global heat trends, and the rising trendline of Columbia River summer temperatures since 1950. Salmon are cold-water fish.  Hot water drains and kills them in several ways, for example in its effects on seasonal migrations out to and back from the sea. (In 2023, 90% of Snake River Sockeye Salmon that entered the Columbia’s mouth died before ever reaching their Sawtooth Valley lakes. Hot water is one reason.)      

Rocky’s story made waves in Northwest hydro, salmon and political ranks. Don’s former utility clients were uncertain how to respond. Don also hit the road for a period, making his case in public presentations to fishing, conservation and scientific audiences in Idaho and eastern Oregon. He was again, in school of another sort, a prepared, persuasive, somewhat demanding teacher. When the New York Times published a story on Snake River salmon science and dams, in 2019, Don Chapman, 89 years old, was quoted. And quoted again in 2021, in another Times’ story in which salmon figured.  

In the end Northwest utilities chose not to start a salmon science argument in public with Don Chapman. Their use of science has since turned anecdotal, opportunistic and often quietly deployed. Northwest utilities no longer attempt a public, evidence-based scientific case against restoring the lower Snake by removing its dams, or offer an evidence-backed alternative to recover Snake River salmon and steelhead.   

In the 1990s, I saw first-hand how Chapman’s field tour of Pole Creek, in the Sawtooth Valley, focused senior federal fisheries staff on badly degraded salmon habitat in central Idaho. In 2021, when NOAA Fisheries reached its belated conclusion that the lower Snake dams must go to prevent Snake River salmon extinction, the agency’s main reason to change its mind was the climatic trends Don had marshalled for his.           

In the 1990s, scientific support for removing the lower Snake dams was solid. Today it is overwhelming, nearly unanimous across fish agencies and in the profession. This has been a persuasive change – for example, to Congressman Mike Simpson, U.S. Sen. Patty Murray, Washington Gov. Jay Inslee, and the Biden administration. Don’s public change of mind was a prominent strand in its creation.  

A career-long Don Chapman design feature is to think deeply, broadly and ahead. It’s no surprise he has thought more closely about how to remove the lower Snake dams than any fish scientist I know. Remember, removing the dams means removing only their earthen sections; most of the concrete and dam works will remain.

Northwest tribes, feds dive into work on salmon revival in upper Columbia River

A lot of sediment is captured around the confluence of the Clearwater and Snake rivers. That’s why every seven or so years the Army Corps must re-dredge to keep its Lewiston “seaport” open. Don sees that sediment as future riparian soils in a restored lower Snake River.  

“If breaching is done hydro-dynamically,” he told me some years ago, “you can use that accumulated sediment. Start with Lower Granite Dam, help the river cut through the sediment to make a canyon, and leave riparian increments as substrate for flourishing terrace systems. Rich soil there. I think much of it could be held in place by irrigated vegetation as the river channel cuts to its old bed level. This has to be carefully done, under engineering control; a multi-disciplinary group could figure it out. Drop the river to cut, not to flush. So some of the sediment stays to rebuild, rather than ending up in McNary Dam pool.” 

And, after a pause: “I bought peaches in the lower Snake canyon in 1963, before it was flooded. The riparian zone was abundant. A valuable 140-mile recreational paradise could develop between Lewiston and the mouth of the Snake, in riparian systems on sediments currently underwater and already owned by the public. That’s on top of the benefit to salmon.” 

Chapman’s work never ended at just ‘fish scientist’

I have made a few brief touch-downs into Don Chapman’s scientific work, and across its breadth. Compressing his international work into two sentences is bad enough, but other large parts of his work get no mention at all. I have also left out his lifetime of fishing, which connects at points to the character and content of his work.  

Fisheries science is a summary term, spanning fields and subfields. Don’s versatile, probing intelligence, and his influence, is found across that span. Field scientist. Developer and tester of research techniques. Advanced analytic scientist. Theorist. Teacher and mentor. Institution-builder.  Communicator to student, professional, political, business, cultural and public audiences. Multi-level connector of fish science to fish management. Senior fisheries consultant. Public scientist. And, for six decades, a leader in his profession.

So I raise a glass, to thank Don Chapman. Fish, rivers, fishermen and women, your profession, and your state are much in your debt. Dorothy Chapman and Don have been together in McCall for 44 years. They have between them six children, and 24 grand and great-grandchildren.   

Author’s note: I am grateful to Bert Bowler, Fred Everest, Russ Thurow, Dave Burns, Steve Pettit, Greg Munther, Richard Scully, Bill Platts and Rocky Barker for talking to me about Don, and grateful to Don for interviews over several years.