ICES CM 2015/A:01 Contribution to the ICES Annual Science Conference 2015 for the Theme Session 'Advancement of Stock Assessment Methods for Sustainable Fisheries' Escaping the Stranglehold by Sidney Holt (Paciano, Umbria, Italy)1 Note. This is an update of a presentation to the ICES ASC (Bergen, Norway, September 2012) entitled: Some Good and Mostly Bad about Maximum Sustainable Yield as a Management Target It is also an expansion of a Presentation in February 2015 to a special meeting of the Committee, on Fisheries of the European Parliament, on Maximum Sustainable Yield in Fisheries Management. In the process it has become a sort of manifesto. 1 [email protected] In a delightful parody of the notion of development a young, ‘activist’ distributed at a recent conference in Brussels, devoted to marine ecosystem conservation, a coffee mug bearing the slogan ‘To Maximum Sustainable Yield and Beyond’. It also carried a linear graph showing total fish biomass rising to the sky! An equivalent idea, posing as a campaign against climate change is that we can control human caused global warming by all of us consuming even more energy so long as it is generated by solar capture, wind, tides, damming more rivers or by nuclear fission, instead of by drastically reducing the production of fossil fuels and not merely the consumption of them. Even the application of an already agreed fisheries management policy, of keeping fishing mortality rates less than what would produce ‘maximum sustainable yield’ seems now to be extremely difficult for the governing Council of Ministers the EU, if not impossible. This notwithstanding the undoubted economic and resource conservation benefits of such a policy. At nearly 90 years of age I don’t have much personal interest left in saving the world. But I shall leave it with the firm belief that science, properly done and used, could do so. I am equally convinced that our political-economic system, based on property, hierarchy and greed, will not permit that. When the First World War had practically led to the destruction of industrial society the Russian Bolsheviks proposed an alternative. But Lenin and Trotsky were right, and Stalin wrong: the Revolution would fail if it did not become global. It did fail. Pope Francis seems to have similar ideas as expressed in his amazing recent encyclical Laudato Si. Here, I try to take a rational view of possible futures for sea fishing as a worthwhile pursuit and important contributor to human food supplies. But I won’t bet on any of them happening. 3 A Manifesto What is Stock Assessment? When I decided to contribute to this Theme Session I thought to begin by defining ‘Fish Stock Assessment’. I had the cosy remembrance that it was a phrase used casually by a group of scientists in late 1949 at the Lowestoft Fisheries Laboratory in England – Michael Graham, its Director, David Cushing, Ray Beverton, and myself, with Basil Parrish, our colleague at the Marine Laboratory in Aberdeen, Scotland and E.S. Russell, Graham’s predecessor. I found no documentary evidence for this, however. An Internet search for use of the term revealed about 50 major published references to it but with a great diversity of meanings and few attempts at definition. John A. Gulland, a next generation scientist at Lowestoft, popularized the phrase and his first book bore it as its title (Wiley, 1977) but with no definition. It appears again in Gulland’s next book (as Editor). ‘Fish Population Dynamics’ (Second Edition, Wiley 1998) as the title of the opening chapter by T. D. Smith: ‘Stock Assessment Methods: the First Fifty Years.’ In what I regard as the best general text on stock assessment and population dynamic – ‘Quantitative Fish Dynamics’ (Oxford U. P., 1999) T. J. Quinn II and R. B. Deriso frequently use the assessment term but in varying ways, and not defined. They do however provide a clear definition of ‘stock.’ The Aggregate of a Population that can be managed as a Discrete Unit. Michael Graham recruited most of the new post- war staff at Lowestoft from among young scientists who had been engaged in operations (British term)/operational (US term) research, groups of mathematicians, physicists, biologists, chemists and others who had used scientific knowledge and method to 2 improve strategy and tactics of the Allied military. P. M. S. Blackett, one of the founders of this new discipline, defined it succinctly as ‘The analysis of data in order to give useful advice.’ Graham regarded the new fisheries science as a peacetime application of their methods. ‘Assessment’ was a frequently used word in the literature of operational research: it seemed to be about the transition from data analysis to the offering of advice. So ‘stock assessment’ became a sort of applied population dynamics, analogous to 2 Mary Jo Nye ‘Blackett : Physics, War and Politics in the twentieth century Harvard U. P., 2004. See especially Chapter 3: Operational Research and ‘Atomic Weapons 1936-1962. 5 the well-known pairs ’pure and applied mathematics’, ’pure and applied physics’ etc. Indeed some of the interests of the stock assessment practitioners were close to the military activities, for example the theories of search for submarines and detection of enemy aircraft and laying of artillery were similar to the theory of efficient search for fish. The application of stock assessment inevitably became closely associated with the problems of managing fishing in order to correct or avoid ‘over-fishing’ but there were evidently other possible applications including the productive development of new fisheries. Here it seems pertinent to refer to one of Michael Graham’s much-quoted maxims. In his classic 1943 book (and, subsequently, in 1955, to a Conference of the United nations), The Fish Gate, Michael Graham expressed his Great Law of Fishing: “Fisheries that are unlimited become inefficient and unprofitable”. I will add that this can happen also to badly managed fisheries, and those for which the market for their products expands geographically or by virtue of a change in their use, such as by shift from human food to fish-meal and oil. Articles and books about stock assessment rarely contain clear, unambiguous definitions of ‘stock’ and, indeed, some usage is ambiguous, one being a ‘management stock’ which could be applied to all the fish in a politically designated ‘management area’ or region regardless of whether it contained a single self-contained biological population. Here I regard the term as generally applying to that part of a biologically self-contained population (of a species of fish or crustacean or mollusc) of interest to humans for exploitation now or in the future. The ‘part’ is usually defined by a lower body size –hence age – boundary, so that eggs and larvae are excluded. From that point of view the stock is an open biological system into which young animals are regularly recruited and from which there is continuous loss by death either ‘natural’ or by capture. If the stock is regarded as occupying a certain space, then it may be necessary to provide for consideration of gains and losses by immigration and emigration. Other inputs to and outputs from the open system, that are usually taken to be of second order interest, are nutrients and excreta. Recruitment is commonly enumerated as the abundance of the youngest cohort in the exploited or exploitable population, the stock. However, for the management of fishing, by some methods –such as by setting maximum 7 catch limits, it is desirable to enumerate the pre- recruits, that is the cohort that will become recruits in the next recruitment period, usually a year. Management policy At an early stage in its career, stock assessment was seduced by an evil vampire with the remarkable name Maximum Sustainable Yield – nicknamed ‘MSY. That was a political act arising from the negotiation of a peace treaty between the authorities of Japan and the USA and most of the Allied Powers, (but excluding the USSR, the Peoples Republic of China and a few others) that came into force in 1952. The US had sought to impose on Japan an abstention principle that would prohibit a country’s fishers from operating in an area regarding the coastal state claimed to be already fully utilising the specified fishery resources. Japan’s delegation wanted to know the meaning of full utilization to which the US response was ‘taking MSY’. This was the invention of a group of US biologists, led by Milner Schaefer, studying the sardine, halibut and yellowfin tuna fisheries of the US who had developed a stock assessment procedure that came to be called Surplus Production theory. MSY was defined as the peak of a parabolic or similar curve of sustainable catch against the biomass of the stock. Two other US biologists – William Herrington and Wilbur Chapman – active both in the political and commercial spheres, pursued, respectively, the ‘full utilisation’ and ‘abstention’ ideas vigorously for several years both in the Americas and in the UN System. But they did succeed in inserting it into a new International North Pacific Fisheries Convention involving the USA, Japan and Canada, but – interestingly - excluding the USSR. The US tried, but failed, to get the abstention principle inserted in the text of the document coming from a Technical Conference on the Law of the Sea convened in Rome in 1955 at the HQ of the FAO of the UN. The US did, however, succeed in putting into the report the idea that MSY is one possible target for managing fishing. No more was heard about abstention in the UN context (partly because of an emerging consensus that the concept of the Territorial Sea could be extended from three or twelve nautical miles to up to 200 miles).