Fish Unlimited: How Maximum Sustained Yield Failed Fishermen

Crown Copyright, with permission of Cefas
Michael Graham, Britain’s chief fisheries scientist after World War II, cleans a fish. Graham advocated restricting fisheries as they developed so that scientists could study the interaction between fish and fishing gear.

The 1930s were a difficult time for the fishing industry. Prices dropped as the Great Depression eroded markets. Fishermen in Europe’s North Sea had an even more difficult problem—falling catches. There had been more than 44,000 British fishermen in 1914, but by 1940, there were fewer than 32,000. Men could no longer make a living fishing.

The problem, according to Britain’s chief fisheries scientist, Michael Graham, was that as soon as fishermen began fishing, stocks started to decline.1 To compensate, fishermen bought bigger nets and engines, but after a certain point, profits would slide. Graham thought the solution was to regulate fishing so that only larger, older fish could be caught. In 1943, he drafted what he called the Great Law of Fishing, a simple declarative statement that summarized the major problem of global fishing: “Fisheries that are unlimited become unprofitable.”1 While some thought that fishermen needed to conserve stocks so their sons could fish, Graham believed fishermen had to change the way they fished so they themselves could continue to make a living.

While Graham viewed the problem in biological terms, policymakers saw that restricting fishing had the potential to compromise the longstanding territorial claims that fishing represented. With the development of marine refrigeration during the 1930s, boats had begun to fish farther from home and stay longer at sea, drawing a host of complaints. Iceland had long been unhappy about European boats fishing off its shores. Mexico and Peru complained about American tuna boats. And the Americans complained about Japanese boats entering the international, salmon-rich waters off Alaska’s Bristol Bay.

Throughout World War II, the Northwest salmon industry tried to prod the State Department into ensuring that once the war ended, the Japanese boats would not return to North American waters. The Truman fisheries proclamation of September 1945 declared that the United States had the right to establish conservation zones in the ocean in order to protect fish stocks that were fully developed. The proclamation did not go far enough for the salmon industry, which wanted Japanese boats explicitly banned from American waters, but it went far enough to cause enormous problems for the tuna industry.

Throughout the 1930s, American tuna boats had ranged south from San Diego, looking for small baitfish like anchovies, which they would use to attract high-seas tuna. A month after the Truman proclamation, Mexico adopted a 200-mile territorial zone. Argentina, Chile, and Peru followed. Iceland acted in 1948, Costa Rica in 1949. The Soviet Union claimed a 12-mile limit and began seizing boats that violated it. Such territorial claims turned fishing into a thorny, foreign policy issue for many countries.

Increasing Cold War tension also caused considerable trouble for the American fishing industry. If countries could restrict fishing, they would set a precedent for other restrictions, perhaps on military vessels. The State Department opposed tariffs on fish imported from its allies, making the fishing industry one of the first to have jobs sacrificed for foreign policy concerns.2 Canadian fishermen, for example, were paid less for the fish they shipped into New England ports. The United States also imported fish from Iceland and Norway as part of its Cold War strategy. The State Department wanted to maintain a wartime air base in Iceland and to provide a market for Norwegian fish so they would not be sold to the Soviet Union. The State Department also wanted to reestablish the Japanese fishing industry and end the American occupation. But the Northwest salmon industry didn’t want Japanese fishing boats back in North American waters. The Southern California industry was equally worried that cheap Japanese tuna would replace American canned tuna on supermarket shelves. When Mexico began seizing American shrimp boats in the Gulf of Mexico, the industry united in demanding that the State Department represent its interests.

By the mid-twentieth century, the world’s fisheries had become contested territories, a trend that was clearly going to continue as improved technology and consumer demand drove fishermen further from their home waters. It became clear to both the industry and the foreign policy experts that the U.S. government would need to play a greater role in protecting the interests of American fishermen. Secretary of State George C. Marshall agreed, and in 1948 created an undersecretary position for fishing. The industry pushed for it to be filled by a University of Washington ichthyologist, Wilbert McLeod Chapman.

Chapman had spent eighteen months during the war stationed in the Pacific, scouting for fish stocks to feed American troops. He returned to the U.S. with a desire to expand American fishing into parts of the Pacific pioneered by Japanese fishermen. Postwar military strategy called for a network of bases throughout the Pacific, and Chapman felt that an American fishing fleet would complement the military’s plans.3

Within months of arriving in Washington, D.C., Chapman crafted the U.S. Policy on High Seas Fisheries. The policy acknowledged that fishing should be regulated in the North Atlantic and affirmed the American right to fish without restrictions off Latin America for baitfish and tuna. It also justified the exclusion of Japanese fishermen from Bristol Bay. The policy was based on a philosophical idea known as Maximum Sustained Yield (MSY). Chapman noted it would “make possible the maximum production of food from the sea on a sustained basis year after year.”4


The Maximum Sustained Yield curve, as published in the Bulletin of the U.S. State Department in 1949. Although the concept drove fisheries management for decades, it was a theoretical construction with no experimental or observational backing.

A month after announcing the MSY policy, the United States signed a fisheries treaty with Mexico. Eleven European countries and Canada agreed on January 25, 1949 to regulate fishing in the North Atlantic through the International Commission for North Atlantic Fisheries (ICNAF). On May 31, 1949, the United States and Costa Rica established the Inter-American Tropical Tuna Commission. All of the new treaties and the two commissions they created were based on the idea that fisheries would be managed to produce Maximum Sustained Yield.

Although Chapman’s high seas policy appeared to conform to the standards of peer reviewed science, the critical document was not actually published in a refereed scientific journal. Rather, it appeared in the Bulletin of the U.S. State Department and contained no formal references. The graph that supported the MSY theory has no numerical scale on the axes—it was a theoretical construction with no quantitative dimension. And it provides no quantitative evidence—indeed, there is no evidence at all—to demonstrate or otherwise justify that the logistics curve bears any relationship to nature and how populations grow and decline. As Chapman presented it, MSY was just an idea, a concept with limited theoretical basis and no experimental or observational backing. The mathematical formulas to establish MSY levels would not be published until 1954.

At the heart of fishery science is the idea that removing some mature fish frees up food and other resources for faster-growing small fish. In dense populations, fish were old and slow growing, resulting in a small annual “crop.” Thinning out the old population through intense fishing replaced the old, slow-growing fish with younger, fast-growing individuals, increasing the weight of the crop, just as thinning trees increased the yield in a forest.5 Fishing produced the conditions that allowed the population to respond; scientists could predict the maximum number of fish that could be taken on a sustained basis, year after year. Or so they thought. But in fact, predicting the catch has turned out to be considerably more difficult than mid-twentieth-century fisheries scientists thought.6

The High Seas Policy briefly quelled various territorial problems related to fishing. However, in 1951 the International Court of Justice at the Hague upheld a Norwegian decision to extend Norway’s waters to four miles offshore. This ruling allowed Norway to nationalize a large area that was formerly regarded as part of the high seas and that constituted an important British fishing area.7 The Norwegian decision was followed by a 1952 report from the International Law Commission (ILC) recommending the creation of an international framework under the Food and Agriculture Organization of the United Nations. The report also recommended that territorial limits be extended from three miles to six.8 That same year, Chile, Ecuador, and Peru asserted wider territorial limits and their right to manage their own waters.9 Two years later, Aristotle Onassis challenged this declaration by sending his whaling fleet into Peruvian waters, where the Peruvian Navy promptly seized it. A Peruvian court found the fleet had been whaling illegally and issued a $3 million fine, paid by Onassis’s insurer, Lloyds of London, which drew Britain into the territorial dispute.10

As the tensions over international fishing escalated, the United States organized a conference in Rome in April of 1955. The conference was designed to head off the Latin American attempt to create international law on a regional basis. It was also an attempt to ensure that restrictions on fishing boats would not set a precedent that would allow nation states to restrict other activities in their waters.11 The United States portrayed the meeting as an effort to provide scientific and technical advice to the ILC. In reality, it was a political meeting orchestrated by the State Department. Despite objections, especially from Britain’s Michael Graham, the meeting voted to adopt MSY as the goal of international fisheries management.

MSY enabled fishing to continue apace until scientists could prove that overfishing had occurred. Only at that point could restrictions such as mesh sizes, area closures, and time closures be introduced to slow the catch. Policymakers in Rome saw fish stocks as essentially resilient, stable populations that had “surplus” individuals that could safely be harvested. There would be little harm if a few too many fish were occasionally taken. Fish bounced back. In fact, according to the proponents of MSY, fishing created the conditions that allowed the stocks to respond. When fishing became unprofitable, fishing would stop, an assumption that did not take into account the increasing subsidies that governments were pumping into their fishing industries.

The State Department and its scientists presented MSY as a policy to conserve stocks, but it allowed the long-range fleets of developed countries to continue to fish where they pleased in the high seas for another two decades. It shaped the fisheries management process by privileging the American preference for bilateral or multilateral agreements, usually with limited jurisdiction and enforcement. It thwarted the creation of an international fisheries agency with broad regulatory authority and enforcement powers. MSY also confined fisheries science to a narrow approach that focused on estimating harvest points in fish populations.12

The ILC adopted the technical recommendations from the Rome meeting in 1956. Two years later, at the start of the Law of the Sea process, MSY was formally adopted as a legal principle. MSY is reflected in most of the postwar fisheries and whaling agreements. As global fish catches steadily increased during the 1950s and 1960s, fishermen and policymakers believed they had adopted a conservative and sustainable fishing regime. But governments were pouring money into fisheries, enabling the technologies developed during the war, such as sonar and radar, to be applied to commercial fishing. The first factory processing ship appeared in 1954. It was capable of fishing and freezing the catch, turning the waste into meal, and staying at sea for weeks at a time.

Ironically, when Garrett Hardin’s “Tragedy of the Commons” paper appeared in 1968, it had the effect of sanctioning still more growth, despite mounting evidence of trouble. The “tragedy” thesis implied that it was impossible to control the “commons.”13 By persuading scientists and the public that overuse of resources was virtually a law of nature, Hardin’s analysis drew attention away from the deliberate government policies that had helped to produce the prevailing situation. Fishing steadily expanded into a powerful global enterprise, operating on the high seas, essentially out of sight, and, for most people, definitely out of mind.

It is generally argued that MSY was a step forward in recognizing that the great sea fishes were exhaustible. However, I argue the opposite. MSY, as it came to be implemented, created a false sense of security in the minds of the public and politicians. There have been various modifications of MSY, replacing the word maximum with other words, such as optimum, or economic, but the modifications have not been substantial enough to prevent fish populations from being overly exploited.

The existence of MSY in its multiple realms—politically, scientifically, and legally—has reinforced the perception that it is based in science, rather than in policy. Its legal constraints have limited the ability of scientists to translate the growing body of ecological knowledge into effective action to conserve stocks. The focus of MSY is on estimating harvest, not on maintaining the population structure of stocks so they can withstand the constant and dynamic changes in the world’s most volatile realm, the great world ocean. The controversial history of the adoption of MSY has been largely forgotten, and so has any understanding of the context in which the decisions were made at the Rome conference.

Despite multiple studies recommending that fishing fleets be downsized, it is very difficult to actually do it. Scientists have to prove that stocks are overfished before regulations can be implemented. And there is fierce resistance when biological models indicate declines. In 1996, scientists working for the Pacific Fishery Management Council, which sets seasons off the coasts of Washington, Oregon, and California, completed new assessments on six commercially-important rockfish species. All were showing signs of decline: two were at less than 10 percent of virgin biomass, triggering provisions of the Sustained Fisheries Act, which had just been passed by Congress. The Department of Commerce declared the fishery a disaster in 2000.

Since then, the council has been engaged in the intensive process of restructuring not only its largest fishery, but smaller sport and commercial fisheries that take a few of the overfished stocks, a problem called bycatch. Environmental groups have also weighed in: Ecotrust authored a groundfish restructuring report in 2003.14 Also in 2003, the trawling industry agreed to participate in an innovative program whereby the federal government contributed approximately $10 million in federal funds and a $36 million loan to help fund a buyback program. Ninety-one vessels and their licenses were retired from the industry. Taxes on the catches of the remaining vessels will repay the buyback costs.15 A vessel monitoring system was implemented in 2007 to ensure that boats were not fishing in closed areas. Fishermen also pay for onboard observers to monitor the catch composition. Six committees were created and have been holding a long series of meetings to determine how the industry could be restructured so the remaining boats could fish profitably.16 The idea is to make the industry more efficient, but also more flexible, perhaps through the use of individual quotas to fishermen and fisheries cooperatives. Implementation is scheduled for next year. But several of the eight stocks currently overfished are long-lived, deepwater fish that only reproduce under certain ocean conditions. The rebuilding schedule calls for widow rockfish to recover by 2015; for yellowtail rockfish, the estimate is 2084.17 Nevertheless, even if they are not perfect, such schemes represent the most realistic solution to fishing problems in the Pacific and other fisheries.

Managers are groping to cope with the realization that MSY has tended to lead to the overharvest of stocks. In New Zealand, managers calculate MSY, then set harvest levels at two-thirds of those values. The European Union is currently looking at its fisheries policies with an eye to reducing their catch. These are all positive steps. The key, as Michael Graham argued back in 1943, will be to regulate the number of boats on the ocean. Fewer boats would mean that fishermen could retain much of the fish they catch, reducing the number of dead fish that are thrown overboard because of catch restrictions. Such programs will be expensive and will sometimes encounter strong opposition from fishermen who are reluctant to comply. Nevertheless, governments and the industry must take firm steps to reduce the number of fishermen. This is the only way to ensure that the remaining fishermen can make a decent living from their profession without further decimating the world’s stocks.