“DANIEL HAS A few recurring obsessions,” Philippe Cury tells me. And it’s true: when he received the International Ecology Institute’s prestigious ECI prize in 2007, the German organization asked him to write a book for their Excellence in Ecology series. Everyone expected a handsome volume on overfishing—but he surprised them by proposing a two-hundred-page book titled Gasping Fish and Panting Squids: Oxygen, Temperature and the Growth of Water-Breathing Animals. Written during a stay in Bremerhaven immediately following Daniel’s time with Philippe Cury in Sète in the spring of 2009, the book is a return to the PhD research he had done in Germany thirty years before. Daniel came back to his “oxygen story” because he had never been able to accept the larger scientific community’s failure to notice his idea, nor its outright rejection by his physiologist colleagues.
Let us reiterate the key events of this story: in 1979, young Daniel wrote a densely theoretical doctoral thesis in which he argued that the growth and maximum size of fish were limited by the surface area of their gills, through which they absorb oxygen from the water. According to Pauly’s theory, in fish and other water-breathing animals, the surface area of the gills (or other respiratory surface) grows more slowly—simply because it is a surface—than the oxygen requirement of these animals, which is a function of their volume. Oxygen supply should therefore be a major limiting factor for fish size. “Among my closest friends and colleagues, my apparent obsession with the relationship between oxygen and fish growth has become a friendly joke,” recounts Daniel, “but I never stopped looking for evidence . . . and what I found was a mountain of information that corroborates my ideas, and which I knew I would have to publish when the time was right.” Now that he had the necessary fame and seniority, the moment had come for Daniel to produce an improved version of his pet theory. His wife Sandra knew the oxygen story like the back of her hand—she had been there when Daniel first thought it up during their first year together in Kiel, on the edge of the Baltic—and she stood behind her husband, encouraging him to “never give up.”
During the summer of 2009, Daniel got to work on a much-improved second version of his beloved theory, though he also took advantage of his sabbatical in Bremerhaven to renew ties with some old friends. He enjoyed a few of Petz Arntz’s home-cooked meals and got together with his old traveling companion Walter Kühhirt, whom he hadn’t seen since the 1970s. The two friends took long walks on the beaches of the North Sea and visited the island of Helgoland, a breath of fresh air that Daniel needed after his frenetic writing sessions. His text vigorously elaborates on the implications of his theory, pointing out that it is both simple and capable of explaining a large variety of biological phenomena. In particular, he demonstrates that fish with larger gills grow faster than the others, that fish under stress (whose oxygen requirements are higher) grow more slowly, and that fish who live in colder, more highly oxygenated water are generally larger.
Daniel’s text is detailed, powerful, and contains a good many practical examples. “I surrounded my favorite hypotheses with a ‘defensive ring’ of arguments, similar to the moat around a castle,” Daniel writes.1 The work is an impressive one, but the editors of the Excellence in Ecology series remained cautious. Otto Kinne, the founder of the International Ecology Institute, writes, “Although it is too early to tell whether the theory underlying this book will become widely accepted, I warmly congratulate Daniel Pauly for the effort.” Daniel managed to convince some of his colleagues, however, including the influential physiologist Hans-Otto Pörtner, but once again, his work was initially snubbed by the majority of fish physiologists, even at his own university in Vancouver. His message did not go over any better internationally: according to my colleague David McKenzie of the National Centre for Scientific Research (CNRS )in France, “That theory is based on a misunderstanding of fish physiology.” Daniel fumed some, but he also knew that with the help of a new heavyweight ally he would win this round, too.
“I GREW UP in the countryside around Hong Kong,” William Cheung tells me. I stop him right there: “Isn’t the countryside around Hong Kong a concrete jungle next to the sea?” William laughs nonchalantly. “No, some parts of the river basin are protected to guarantee the city’s water supply, or at least they were when I was a kid. I was actually surrounded by a protected environment with a view of the China Sea, where I had a lot of experiences with the natural world that really made an impression on me.” The young William chose to study biology, and his master’s thesis was directed by the energetic Yvonne Sadovy de Mitcheson, a London native and new professor at the University of Hong Kong who had also worked in Puerto Rico and the Bahamas. “Yvonne is very enthusiastic,” William recounts. “She was the one who exposed me to Daniel’s work in the 1990s. Like every marine biology student, I wanted to go scuba diving and count fish. Yvonne suggested something a little more ambitious—looking at how Hong Kong’s fisheries and marine ecosystem had changed during the second half of the twentieth century.”
William spent two and a half years assembling all the information available in various libraries, interviewing 150 fishermen, divers, and functionaries, making an Ecopath-type model, and reconstructing fishing statistics as best he could. This allowed him to identify marked overfishing starting in the 1960s and to propose better management solutions.2
“At the time, we weren’t able to use Ecopath in Hong Kong, and Yvonne sent me to Vancouver for three months in 1999. That experience changed my life. I was exposed to all kinds of new ideas. Daniel was just beginning the Sea Around Us project, and there was this great sense of inspiration. After that, I knew I wanted to go back to UBC for my PhD, but I spent two years working for the WWF first.” When he did return to Vancouver, his thesis director was Tony Pitcher, who helped him create statistical models to estimate the vulnerability of different fish species to overexploitation and extinction.
But Daniel was never far from this student who, he says, “had a real head for numbers.” When William’s PhD funding ran out in the mid-2000s, Daniel offered him a contract with the Sea Around Us, asking him to refine their distribution models for different fish species. William found himself “on the shoulders of giants,” as he puts it—he benefited from both FishBase and the experience of colleagues Reg Watson, Chris Close, and Vicky Lam, who had already spent several years thinking about the best way to predict the distribution and abundance of fish exposed to both fishing and the warming of the oceans. Indeed, if the effects of overfishing are already well known, we are only just beginning to understand how climate change will affect fish populations. Oceanographers have known for a long time that warm waters are less productive—their beautiful, translucent blue color only betrays the sheer emptiness of these biological deserts. Fish find less food there, and the water is lower in oxygen, which is, of course, essential for their growth and survival.
Slowly but surely, William would figure out how to simulate the impact of global warming on the oceans and fisheries worldwide. He became an expert in this area and built an international reputation, publishing increasingly prestigious scientific articles that have been cited by thousands of his colleagues. In particular, he led the Sea Around Us team that, along with colleagues at Princeton, estimated what the distribution ranges will be in 2050 for more than a thousand species of fish and marine invertebrates exploited by fisheries all over the world.3 To accomplish this feat, the researchers used the climate change scenarios published by the IPCC in 2007. Their seminal study showed that because of human-induced climate change, numerous marine species will soon disappear from the tropical and subtropical regions, which will become too hot, while the polar regions could find themselves invaded by species from lower latitudes. According to Cheung and his coauthors, this scenario could lead to a dramatic replacement of 60 percent of species currently present in these regions and have serious consequences for marine ecosystems and food security in tropical countries. In fact, the same team, still under William’s leadership, published a second study shortly afterward indicating that the fisheries that will benefit the most from global warming between now and the year 2055 are in Norway, Iceland, Greenland, Alaska (United States), and Russia, while the biggest losses will be seen in the Pacific, China, and from Indonesia to Ecuador. The irony of the situation is that the Global North could actually be “rewarded” for their massive greenhouse gas emissions by a huge influx of fish in their waters.4
But is the “tropicalization” of the oceans already happening? Like any good biologist, William already knew that most species of fish cannot survive outside of a specific thermal zone (with the exception of large sharks and tuna). He therefore decided to calculate the average temperature of the water where each exploited species lives. “I spent a whole summer compiling the data,” says William, who stayed at the office while everyone else went to the beach. With help from Daniel and Reg Watson, he processed data from the Sea Around Us’s impressive stores for a thousand fish species living in fifty or so large marine ecosystems around the globe. His analysis revealed that the average temperature in the ranges of exploited fish had indeed increased by 0.7°C (1.26°F) since the 1970s.5 This difference may seem small, but in an underwater world that is extremely sensitive to changes in temperature, such an increase is significant and clearly signals that warming is already under way.
William completed and improved his statistical models of the distribution of marine species by taking fish physiology into account. “In the summer of 2009, I was in the UK, and I took a side trip to see Daniel in Bremerhaven,” William recalls. “He was neck-deep in his ‘oxygen story,’ and he had me read his doctoral thesis, which really impressed me.” William integrated an additional constraint into his statistical models, taking into account the oxygen content of the water and its effect on fish growth and size. Daniel was overjoyed: “I gave William the keys to a Ford Fiesta and he came back with a Rolls Royce!” Indeed, William had illustrated Pauly’s theory beautifully, calculating that for six hundred fish species, the maximum size of individuals could fall by 14 to 24 percent by 2050 as a result of global warming.6
But the scientific controversy remained intense. In March of 2017, Sjannie Lefevre and Göran Nilsson of the University of Oslo, along with David McKenzie of the CNRS, published an opinion piece in the journal Global Change Biology, titled “Models Projecting the Fate of Fish Populations Under Climate Change Need to Be Based on Valid Physiological Mechanisms.” 7 According to these authors, gill lamellae, which transfer oxygen into the bodies of fish, are like the letters on the pages of a book, whose numbers can increase with the book’s volume. Thus, gills’ surface area growth and their capacity to extract oxygen from water go hand in hand with the fish’s volume and its metabolic requirements: the availability of oxygen should, therefore, not limit the growth or maximum size of animals that breathe underwater.
Daniel’s response, also signed by William, came quickly, and reading it, you can’t help but feel sorry for the young Norwegians who defied the old master.8 In energetic prose, Daniel advances a slew of arguments in favor of his theory. “I’ve always had trouble getting people to understand how gills work,” he tells me, “but I’ve finally found the right metaphor: they’re like the radiator in a car, the surface of which limits the capacity of the motor”—unlike letters in a book. More scientifically, Daniel and William explain that gills are organized into lamellae, and that a given gill surface can only hold so many lamellae.
As he regales me with the details of his most recent game of academic ping-pong in the fall of 2017, I can sense how much Daniel enjoys these public skirmishes. But the party wasn’t over yet: the other team parried soon after.9
Other battles rage on as well. The most striking pits Daniel against his American colleague Ray Hilborn. Yet another mustachioed scientist, he is only eighteen months younger than Daniel. Like him, he became a fisheries scientist by chance in the 1970s, and like him, he is a big name in the field, known for his many publications, prestigious works, and the awards he has won. Hilborn grew up in California and studied under Carl Walters at UBC. Since 1987, he has been a professor at the University of Washington in Seattle, only about 120 miles south of Vancouver. Well-spoken, Ray describes his first encounter with Daniel in 1988 as follows: “The first time we met, flying from Halifax to Toronto after a conference, he spent the flight outlining faults in my presentation and listing in great detail all the work going on around the world that I had not referred to, and in truth, was unaware of. I learned that when in need of a good critic, sit next to Daniel Pauly.” This anecdote can be found in the preface Hilborn wrote for Daniel’s 1994 book On the Sex of Fish and the Gender of Scientists: A Collection of Essays in Fisheries Science. Hilborn’s text is teasing but mostly laudatory, even describing Daniel as “the most widely cited fisheries scientist of his generation” (and therefore more cited than Ray himself, which is still the case today). At that time, Hilborn and Pauly were mostly in agreement about what was wrong with fisheries and about the need to improve their management. They strongly disagreed, however, about how to handle the statistics. Daniel and his team developed ELEFAN and other methods suited to the sometimes difficult research conditions in the Global South, but such approaches were often criticized by colleagues from the North, including Hilborn. Ray is, in fact, the author of the famous quote, “The Prophet Daniel is among those excluded . . . Daniel must toil in infernal heat, deprived of holy catch-at-age data and armed only with a thermometer” 10—though he probably wrote it without knowing that the target of his ire had grown up an outcast.
Ray Hilborn, a white North American conservative, and Daniel Pauly, a mixed-race alter-globalist with Marxist leanings, are worlds apart. But they share the same pride and ambition, as well as a quarrelsome nature. They crossed swords more frequently as time went by, and the tension mounted even as Daniel’s notoriety increased—in the early 2000s, the press crowned him “the Fisher King.” 11 But Daniel was not Hilborn’s only target: “Ray Hilborn and Carl Walters had been criticizing Ransom Myers for a long time,” Boris Worm tells me. The Hilborn-Walters duo were also some of Boris’s most virulent detractors in 2006 when he predicted the collapse of marine fisheries by 2048.12 But Boris chose to respond diplomatically: he swallowed his pride and invited Ray to a synthesis workshop on global fisheries. The results, which aimed for a reassuring tone, were published in Science three years later.13 Boris invited Daniel as well, but he declined in order to “avoid a pissing contest” with Hilborn. Instead, he sent Reg Watson and Dirk Zeller to represent their team.
“Since we had worked together, it was harder for Ray to come after me,” Boris told me with a laugh, “so he threw everything he had at Daniel.” When I interview him at his farm in Washington State, Ray describes himself as a rationalist who is generally skeptical about his colleagues’ work and who promotes a “pragmatic” approach to managing marine ecosystems. He freely admits that the methods and databases (FishBase, Ecopath) developed by Daniel and his team are very useful to the research community, but he knocks their reconstructions of fishing statistics as “an absolute waste of time” and marine reserves as the con of the century: “Well-managed fisheries do not need marine protected areas,” Ray declares. He is, therefore, not the least bit upset about Donald Trump’s plans to open up the largest marine protected area in the world, located in the middle of the Pacific, to American fisheries. Ray insists that the oceans need to be exploited on an industrial scale in order to feed humanity, arguing that such exploitation would be much less harmful to the planet than intensive agriculture. To achieve that end, he finds it perfectly reasonable to “massively overfish” large, predatory fish species in order to increase the yield of smaller fish. Hilborn considers the Paulyesque vision of the oceans to be “catastrophist” and says that “a major challenge for fisheries management is posed by environmentalism.” 14 According to Ray, Daniel and the NGOs who rely on his work are using the fear created by their apocalyptic vision of the state of the ocean to drum up more funding.
Funding also turns out to be an interesting topic in Ray’s case: “My attitude is, actually, I’d like to take money from everybody,” Ray tells me. “I’ve received funding from environmental NGOs . . . I’ve been very successful in these last few years at getting increasing amounts of money from the fishing industry.” This last source seems to make up the majority, however. In the spring of 2016, at the end of a European conference tour, Ray made headlines in a less-than-flattering way. The French newspaper Le Monde published a full page on him titled “Ray Hilborn, a fishing expert in the eye of the storm.” 15 The article declared that “Greenpeace has published compromising documents on an influential American fisheries scientist’s conflicts of interest.” In particular, they accused Hilborn of “taking 3.56 million dollars in funding from fishing-related interests, or 22 percent of his total funding for research and knowledge sharing” for the period between 2003 and 2015.* “According to Greenpeace,” the article continues, “no less than sixty-nine organizations with ties to the fishing sector—businesses, foundations, professional associations—have supported the famous scientist’s work . . . In addition to this funding, the scientist has also received personal payments.”
What Greenpeace denounced was not the fact that Hilborn had used funds from those sources, but that he had not systematically declared a conflict of interest in his scientific publications, in accordance with standard practice. As an example, Le Monde cites an episode in 2010 where “Ray Hilborn wrote a letter to Nature in support of the Marine Stewardship Council (MSC), an organization whose goal is to guarantee that fisheries are exploited sustainably. The well-known label had been called into question by certain researchers. Two years later, he authored, alongside several other scientists, a study that was favorable to the MSC in the journal PLoS One. In both cases, he failed to declare that, between 2008 and 2010, he had worked as a paid consultant for one of the certification companies used by the MSC.”
The association France filière pêche,* which had invited Ray Hilborn to Europe, was embarrassed. According to Le Monde, “the association states that they only compensated the researcher for his travel expenses and those of his spouse.” 16 Eighteen months later, I ask Ray to tell me about the events that followed. He says that the journal editors had looked into it, but concluded that he had done nothing wrong, and, he adds, “The University of Washington said I hadn’t violated any rules.”
Daniel and Ray are both septuagenarians now, but their intense rivalry confers a sort of eternal youth, and just a hint of mischievousness, on both of them. Ray turns out to be a good sport after all, ending our interview with the following anecdote: “Several years ago I gave the Peter Larkin Lecture at UBC, and Daniel introduced me by saying that he thought my coming to UBC was like the Pope going to Mexico and telling people they didn’t need birth control—this in reference to my skepticism of the benefits of marine protected areas in many places.”
* Ray Hilborn’s research had therefore received a total of 1.2 million dollars in funding each year.
* An interprofessional association that includes members from all sectors of the French maritime fishing industry.