In Memoriam Colin Clark, FRS

June 18, 1931- April 12, 2024
By Leah Edelstein-Keshet

The loss of Prof. Emeritus Colin Clark on April 12, 2024, marks the end of an era that began some 53 years ago, when he established a theme of Mathematical Biology within the Department of Mathematics at the University of British Columbia.

Colin Clark was born and raised in Vancouver, BC. He obtained a Bachelor of Arts at UBC in 1953 and received his PhD at the University of Washington in 1958. Although he did a two-year stint at the University of California, Berkeley, his love of the Pacific Northwest drew him back to Vancouver, where he joined the Department of Mathematics in 1960. He spent his first 12 years at UBC establishing a reputation in mathematics, and publishing numerous papers in the areas of partial differential equations, functional analysis, and spectral theory. (Even in this “early phase”, there was a hint of his eventual turn to biology with his 4-page paper in 1967 entitled Rellich's embedding theorem for a “spiny urchin”, that appeared in the Canadian Mathematics Bulletin. Alas, the “spiny urchin” is an irregular connected open set in R2, a bit removed from the sea urchin of aquatic habitats.)

Colin “saw the light” in 1971, and published his first paper in mathematical biology entitled “Economically optimal policies for the utilization of biologically renewable resources” in Mathematical Biosciences. He never turned back. Always the innovator, he founded several entirely new areas of mathematical-biology research. The first, as evidenced by his 1971 paper, was Bioeconomics. The second field, in which he continued to be prodigiously productive, was Behavioural Ecology. Colin established dynamical programming as a key tool in understanding the ecological implications of animal behaviour.

In 1974, another equally brilliant mathematician, Don Ludwig, was recruited from New York University to UBC. Originally a researcher in PDEs and waves, Don took a liking to Colin’s work, and quickly switched from waves to mathematical ecology and fisheries. According to Colin, his own later switch from bioeconomics to behavioural ecology stemmed as much from an impulse to “keep Don Ludwig on his toes” as from a disgust with government officials who refused to listen to sensible advice about resource management policy. “At a conference on Fisheries, Colin introduced himself [to a government bureaucrat], they shook hands, and then the guy turned around and walked away, apparently wanting nothing to do with the possibility of being enlightened [by the expert]”, an anecdote recalled by James Carrell (Professor Emeritus, UBC). At the collapse of the Atlantic Fisheries in the early 1990’s, Colin was said to be heard frequently mumbling “I told you so!”

Some of the many subjects in mathematical biology in which Colin worked and published include bioeconomics (his book entitled Mathematical Bioeconomics: The Optimal Management of Renewable Resources is a classic in the subject, with 3rd edition published in 2010). According to Professor Rashid Sumaila, (FRSC, Killam professor, Institute for the Oceans and Fisheries UBC) “[This is] still a must-read book for students and scholars of fisheries economics, science, and management.” Colin worked on dynamics of animal populations, applications to various fisheries including Antarctic whales and Gulf of Carpentaria prawns, and marine mammals, search theory, modeling of natural resources, behavioural and evolutionary ecology, and applications of dynamic optimization theory. Colin collaborated with biologists and economists at UBC and elsewhere, and worked with provincial, federal, and international resource management institutions. Several professors in biology departments at UBC and SFU continue research directions founded by Colin. “I've met many biologists who talked or worked with Colin, and all - including me - count this as inspiring and fortunate,” says Professor Ron Ydenberg (Director, Simon Fraser University Center for Wildlife Ecology). Colin continued many new and exciting research projects, publishing new papers and books with unabated productivity after retirement.

Colin Clark, together with Don Ludwig, and later Robert Miura, were the founders of Mathematical Biology at UBC. After a long hiring-freeze due to a downturn in the economy in the 1980’s, they heroically fought to recruit other young people, among them myself (Leah Edelstein-Keshet, in 1989), enabling a graduate program in Mathematical Biology, a seminar series, and local regional workshops (The Pacific Northwest Workshop in Mathematical Biology, PNWWMB) to be initiated. After the retirements of Colin and Don, (and later of Robert Miura, who went on to another career at the New Jersey Institute of Technology), it was unclear whether math-biology would go extinct or survive in the UBC Department of Mathematics. In later years, this interdisciplinary subject was rekindled and is now among the strong and proud mathematics groups at UBC – and we owe it all to Colin Clark, who founded it over 50 years ago.

Throughout his career, Colin was an avid hiker, and outdoors-man. Sir John Beddington (CMG, FRS, Former Professor of Applied Population Biology, Imperial College) describes hiking trips in the Cotswolds, Yorkshire Dales, Devon, Cornwall and Welsh mountains. Companions included ecologists who “became rather well known”, such as Lord Robert May, Sir Roy Anderson (FRS), Sir John Lawton (FRS).” Sir Beddington adds “Colin was a very professional bird watcher and often would demand we stop at obscure parking spots where rare migrants were to be seen… I remember one occasion where we searched ... for an ordinary looking house. On entering the garden, we were greeted by a line of chairs, mosquito repellent, and hundreds of humming birds.” Colin became an ardent nature lover after hearing a lovely birdsong while hiking. He had to know the name of that bird. UBC Emeritus Professor David Boyd writes about local BC hiking trips. “He knew all the species of birds, butterflies and flowers that we would encounter.”  Professor Pauline van den Driessche (Emerita, University of Victoria) recalls “a hike [in the 1990s] to Mt. Work in the early spring when the Satin flowers (Olsynium douglasii) were in bloom… Naturally, [Colin] told us about birds that were around there. Happy times!” Prof. Ron Ydenberg described travel “to a remote Amazonian field station where Colin spent many hours in a treetop blind (reached via a very long ladder) from which he could look directly into the canopy. One colleague told me that he visited the blind not to watch birds, but to get a chance to talk with Colin. They ended up developing a model together, and he got turned on to birdwatching.”

Colin retired early in 1995. (Interestingly, in that instance, Colin “copied” Don, who had decided to retire the same year.) Retirement allowed more time to pursue hobbies such as birdwatching.  Colin visited some of the most exotic places on Earth in pursuit of rare birds.

Throughout his career, Colin was also an energetic and productive garden-farmer with his wife Janet Clark.

Colin’s influence affected many people, personally and professionally. “I have strong memories of Colin from my undergrad at UVic … He was a fantastic lecturer… he was a real inspiration to me.. I will miss him greatly”, says Professor Mark Lewis (FRSC, Emeritus at University of Alberta, and University of Victoria Kennedy Chair). One of Colin’s coworkers, Marc Mangel (Distinguished Professor Emeritus, UC Santa Cruz) says “I .. knew [Colin] for more than 2/3 of my life and he knew me for more than half of his life ... I worked with Colin [almost continuously since 1976] as a grad student, research assistant, young faculty member, and then -- as we both grew older -- as a senior faculty member”. Former students of Colin Clark describe him as “kind, generous, and an excellent mentor,” according to Marty Anderies (Colin’s PhD student 1993-1998 at UBC, now a professor at Arizona State University), who adds “I was lucky and honored to have studied and worked with him.” Professor Jon Conrad (Cornell University, a coauthor) writes “I know he was a positive influence in the trajectory of my career and the careers of his students.” According to Professor Simon Levin (McDonnell Distinguished University Professor, Princeton University), “[Colin] left behind a bevy of friends, colleagues, collaborators and students, and generations who built their work on the foundations he created”.

Colleagues fondly recall stories about Colin. Ron Ydenberg described watching Colin “step casually over a very large rainbow boa that lay over the path between the wash- and bunkhouses” in an Amazon field station. “When an obviously angry snake escaped from a bag (for some reason hung in the canteen during lunch), [Colin] sprang up onto a chair as quickly as everyone else when the herpetologist who had collected it remarked that it might be venomous. In spite of the rudimentary facilities, the only thing Colin disliked about that visit was that every meal served in that canteen was heavy on cilantro, which he loathed.” Others recall Colin’s advice. Mark Mangel says: “Three things that I learned from Colin are i) Never compare yourself to anybody else, but ask if you are doing the best you can; ii) Do not let not lack of knowledge about a subject prevent you from working on it (which we did both with the tuna-porpoise fishery models in 1976-1979 and then our forays into behavioral ecology in 1982 onwards), and iii) How to work with, encourage, and mentor young scientists.”   Leah Keshet remembers Colin’s famous story about an important project for which he was funded. “Colin hired a student to work with him. For the first year or so, little progress was made. It got to the point that the partners avoided one another out of sheer embarrassment. (Their offices were at opposite ends of the Math Annex, so they would often sneak down different staircases to avoid an inconvenient encounter.) Eventually, when the reporting deadline loomed, they finally sat down to work, and achieved a breakthrough. The moral of the story, according to Colin, is `No need to stress! Important things will get done!’”

“In my opinion, Colin Clark is arguably the most influential bioeconomist of his generation”, writes Prof. Sumaila. “Colin was one of the most brilliant, most generous, and most jovial of all of my colleagues”, says Simon Levin. Colin is survived by his wife, Janet, and his son and daughters, Graeme, Jennifer, and Karen. Those of us who knew him as a role model, mentor, and friend will miss him, and remember him with great fondness!