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The concept of a generalized theory of population dynamics is probably premature and may even be illusory. The 'overfishing problem' has its roots in the economic organization of the industry. The century since the Norwegian government had hired G. O. Sars to investigate the fluctuations in the Lofoten Island cod fishery saw the development of many national and several international fishery research programs. Although these were too frequently focused on the needs for immediate answers to short-term management problems, many of the programs produced fundamental insights into the effects of fishing on marine fish and mammal populations. These insights were primarily in the area that Kyle in his 1905 analysis of overfishing termed ‘the problem of the decrease of fish.’ This problem, which Kyle had argued ‘can be solved if certain factors are known,’ was in fact solved in three different ways by the early 1950s, as described in chapters 7, 8, and 9. In 1954, three papers elaborating these three partial theories were published. Schaefer (1954a) defined the surplus production theory with his application of the logistic equation to the California sardine fishery in his paper ‘Some aspects of the dynamics of populations important to the management of the commercial marine fisheries.’ Ricker (1954) defined the spawner and recruit theory, using data from populations of herring, haddock, salmon, starfish, and fruit flies in his paper ‘Stock and recruitment.’ [ABSTRACT FROM AUTHOR]

How far … then mathematics will suffice to describe, and physics to explain, the fabric of the body, no man can foresee. The value of using mathematics in the study of biology has been advocated by philosophers and some biologists since well before the mid-1800s; the dangers of allowing its overwhelming deductive power to control the biologist's thinking has been argued just as long. Despite the purported dangers, however, in the late 1800s and the early 1900s mathematics was beginning to be applied to many biological systems. For example, Heincke in his study of the races of herring criticized his colleagues for their ‘aversion toward measurements and numbers’ while at the same time acknowledging their reticence to use this tool because, as he put it, ‘many of them have no mathematical sense, and no schooling in mathematics.’ Heincke's use of mathematics was, however, primarily statistical and descriptive of what he had measured, involving a rigor that he saw as essential if one ‘demands that his labours be regarded as a contribution to the knowledge of the true laws of nature’ (see Sinclair and Solemdal 1988 p. 195). In 1917 D'Arcy Thompson published a book titled On growth and form, which relied heavily on mathematics from a different point of view. Oriented primarily towards describing the growth of organisms, he relied on mathematical descriptions of their patterns of growth and morphology. [ABSTRACT FROM AUTHOR]

[T]he fluctuation of year classes [is] a prominent, perhaps the predominating factor determining fluctuations in the fisheries. Hjort's conclusions that the fluctuations in the catches were due, at least in part, to the large variability in the numbers of young herring and cod surviving from each year's spawning were accepted by almost all scientists by 1920. While D. W. Thompson continued to argue that herring scales could not reveal age precisely, and hence could not be relied on to reveal fluctuating age compositions as Hjort claimed, many other scientists began to demonstrate similar fluctuations in age frequency distributions for other species of fish. Armed with Hjort's answer to the question posed to Sars now more than a half century earlier, and with the results of the ‘War Experiment’ demonstrating the effects of reducing fishing intensity, scientists entered the 1920s with a sense of optimism. One cause of the fluctuations of fish populations was known, and the possibility ‘of turning our knowledge to the practical guidance of the fishermen’ (Thompson, H. 1929) by predicting future catches began to attract the interest of several biologists working in the North Sea and in North America. Three approaches were taken. One was based on monitoring the varying age distributions by directly sampling the commercial catches or, using research vessels, sampling the population itself. This approach achieved moderate success for the North Sea haddock and East Anglia herring fisheries. [ABSTRACT FROM AUTHOR]

We now come to the difficult and so far very obscure question, 'what causes the irregularities in the … fisheries … which have been observed from time immemorial?'. … [T]his phenomena, like everything else in nature, must have its natural causes, which can be found … only … from a scientific point of view. Sars' early opinion, that the question of the fluctuations in the catches was solvable but that it had to be approached from a scientific point of view, had been firmly adopted by 1890. The research programs that had been established in the preceding two decades in Russia, Norway, the United States, Scotland, Germany, England, the Netherlands, and Denmark were making rapid progress in developing the basic scientific methods needed, but were making much slower progress in developing answers to Sars' ‘obscure question’ on the causes of the ‘irregularities’ in the catches. In the 1890s fishermen had two main complaints, as Cunningham, the biologist at the Marine Biological Association (MBA) in Plymouth, outlined (Cunningham 1895a p. 54): ‘the capture of immature or undersized flat-fish, and the decrease in the supply of the more valuable kinds of these fish.’ The fishermen's argument was that the former caused the latter, and hence, that suitable regulations on the catching of small fish would remedy the problems of the fisheries. The fishermen's first concern, the effects of the capture of small or immature fish, was often referred to as the ‘small plaice problem.’ [ABSTRACT FROM AUTHOR]

[P]robably all the great sea-fisheries, are inexhaustible.… It is a mistake to suppose that the whole ocean is practically one vast store-house. The differences in opinions about the causes of the fluctuations in the catches of fish described in chapter 1 came into clearer focus in London between Monday 18 June and Friday 20 July 1883. The occasion was the Great International Fishery Exhibition, and two of the most influential scientists in England offered their opinions on the effect of fishing during public lectures. Thomas Huxley argued that humanity's efforts could have no effect on subsequent catches, while Ray Lankester argued that catching female fish resulted in the absence of the young fish that they would have produced, and that this absence had an effect. These two opinions had important economic and political consequences, and were similar to ideas expressed in a report on the state of fisheries laws commissioned by landlocked Austria a few years earlier (Peyrer 1876 p. 670). He noted arguments by some that ‘the disregard of all protective measures, and of all regulations limiting the methods of fishing, will, in the end, prove disastrous to the salt-water fisheries, in the same way as with our river and lake fisheries,’ while others demanded ‘complete freedom from all those limitations which only quench the spirit of enterprise.’ [ABSTRACT FROM AUTHOR]