Abstract: In contrast to the situation in which animals are raised, where access to food is recognised as economically important, food availability has not been included as a parameter in economic models for fisheries management in the commons of the sea. Analogies are drawn between management of common pastureland and common fishing grounds with regard to optimising yield.

In animal husbandry, food availability is recognised as being of central importance; this applies also in fish farming. By contrast, food availability has not been included in the economic models for the exploitation of the commons of the sea, i.e. the fishing grounds. In two articles in Nationaløkonomisk tidsskrift Warming, the first economist to treat the question of the management of common fishing resources, showed how it could be ensured that the effort expended on fishing would not be too great. In the first of these (Warming 1911), he outlined how not too many fishermen should be allowed to engage in fishing in a specific area, and in the second (Warming 1931), referring to eels, how not too many traps should be laid. However, these articles did not attract attention among economists. Warming did not take food availability into account in his studies.

The management of common fishing grounds first became an issue in economics in the 1950s, with two articles in the Journal of political economy, the first by Gordon (1954) and the second by Scott (1955). Gordon (p. 127) addresses the question of nutrition, only to dismiss it as irrelevant for the yield in a common-property resource, and the food supply is never included as a parameter in his models for control of fishing effort. Scott presented his essay as a continuation of Gordon's article, but he also does not include food availability as a parameter. Ever since, studies by economists of the management of marine fishing have focussed on models of this type, without including food availability as a parameter. This can be seen from relatively recent studies from Scandinavia. Hannesson (1993) notes (p. 32) that the consequences of catches over a given period for the catch in future periods must be evaluated. In this connection, he states that the reason for variations in the growth and renewal of the stock are not well understood, but he does not explain the problem in such a way as to enable biologists to make a contribution to models for optimum fisheries management. In Chapter 3 he notes that the catch may depend on the extent to which selective fishing gear is used, i.e. gear that catches fish of a particular age and size, but his study does not include a consideration of access by the fish to food. In his analysis of variations in the size of a fish stock, he takes as an example the Norwegian-Arctic cod (section 4.23) and assumes that the growth of the fish from year to year may depend on their access to food, but states explicitly his intention to avoid taking variations in the growth of the fish into account in his study (p. 83 and again on p. 89). His last chapter (5), which deals with methods of fisheries management, makes no mention of access to food as a parameter.

Two Finnish scholars, Kaitala and Lindroos (1998), examine a game theory scenario in which three states collaborate on the management of fish stocks that cross their common borders. The biological parameter for management is the size of the fish stocks; no attention is given in this analysis to the control of other factors such as food availability.

The above examples illustrate the fact that food availability has traditionally been ignored as a parameter for managing marine fishing.

Two doctoral theses from Denmark and Norway, "Property rights based regulation of fishery: Applications and theory" by Vestergaard (1998) and "Six essays on resource rent sharing" by Matthiasson (1998), can be taken as an indication that access to food still receives no attention in economic studies of fishing in the sea in the Nordic countries. As evidence that access to food as a parameter for optimal fisheries management has been ignored in academic literature from outside the Nordic countries, we can take the collection of articles The politics of fishing (1998) in which fishing quotas are the parameter, and the article "A model of regulated open access resource use" by Homans and Wilen (1997). Homans and Wilen mention methods other than the regulation of total catch (i.e. by quotas) as instruments in optimal fisheries management, such as the control of the mesh size of nets, but they do not relate these to food availability for the fish.

Finally, concerning management models within the single species context, two studies in the Journal of environmental economics and management can be taken as examples of how food availability is ignored in the study of economic fisheries management. Danielsson (2002) discusses two types of fisheries management: catch quotas and effort quotas. His model allows for environmental factors as a cause of stochastic variation in the growth of the fish stock. Nevertheless, the food supply is not included as a parameter in the model. Weitzman (2002) analyses landing fees and catch quotas as instruments in fisheries management. He acknowledges the existence of ecological uncertainty, but even so does not include observations of food availability as a basis for regulating fishing.

In the case of competing fish species we take as an example a study by Flaaten (1991). He notes that access to nutrition may constitute a limiting factor in the competition between the species. As Flaaten shows, it is normal in models for competing fish species to reflect the fact that the size of one species influences the size of other species due to food limits, but neither Flaaten nor others examine how competition between individuals of the same species for a limited food supply can influence the stock yield.

A survey of papers from recent international conferences on managing marine fishing doesn't change the above conclusion that food availability is ignored as a parameter in that field.

Under natural conditions, life is regulated by supply and demand. The food supply is limited and undergoes fluctuations, while demand is determined by the number of living organisms in the various year-classes, and also exhibits fluctuations. Agriculture involves keeping the size of herds proportionate to the available food. A sensible sheep farmer will keep the number of sheep down in relation to the fodder at his disposal. Unless he increases the fodder crop considerably, he will have to slaughter most of his lambs in the autumn. When the sheep are grazing in the uplands, the quality of the nutrition they receive is not his sole responsibility: the body in charge of the common pasture decides how it is to be utilised. The body may not have any refined model for the management, but the way of thinking of the relations between nutrition and the result measured in slaughter weight is a model. In many ways, the utilisation of such common resources is similar to that of common fishing grounds, as will be examined below.


Management in the commons of the grazing of sheep in the uplands and of cod stock in the sea: a comparison

In agricultural science the relation between nutrition and yield in a common sheep pasture is viewed as being self-evident. Similarities for the commons of the sea are here assumed as cases of applied biology on land and on sea. This assumption can be applied until it has been disproved; we take the liberty to claim that agricultural science is more established than fisheries biology.


1. Adequate access to food from the outset

The body in charge of a common pasture must decide each spring when the sheep may be driven to the uplands. This must not be done until adequate grazing exists so as to ensure that the ewes will have enough milk for their lambs to enable them to develop properly.

The situation with regard to cod is not quite similar, since man cannot directly influence cod migration. Cod will move to a place where they find enough to eat, and will move away from a place where they do not find enough. Man does not decide whether the cod move; man does not decide when or how they concentrate in particular areas on the fishing banks, but man does influence, through his fishing and fishing methods, how many of the various year-classes will be found on the fishing banks. In this respect, management for the optimisation of cod fishing involves the observation of the condition of the cod of various ages, and rational control of fishing involves catching and killing sufficient numbers of both young and old cod so that food will be sufficiently available for all year-classes.

Primarily, it would be a task for fishery biologists to give information in a given situation, and then a task for economists to put the biological information in a model for economic management of the fishing.


2. Protecting the resource

In a common pasture in the uplands, the resource consists of vegetation. In order to protect this resource, it is important not to drive the sheep to the uplands so early as to damage the vegetation. There are grounds for believing that if this is done too early, the consequences will become apparent in the condition of the animals earlier than the vegetation will show the result. It is the responsibility of the body controlling access to the common pasture to ensure that the sheep are not driven to the uplands until the vegetation can tolerate grazing.

The marine resource that can be compared to the vegetation from which grazing animals draw their nourishment is the cod's food, which consists of various species. The nutritional conditions can be evaluated by examining the condition of cod of various ages. Man has no means of slowing the migration of the cod to the fishing banks, but he does have the means to keep the size of the various year-classes within the limits that will ensure that the cod will be in good condition. Management for the optimisation of cod fishing will involve observation of the condition of the cod, and the rational control of cod fishing will involve measures to ensure that the fish will have a sufficient supply of food to be in good condition, using fishing gear that will ensure that sufficient numbers of young fish will die and maintaining catches at a sufficiently high level.

Here, there is need for scientific advice, built on a model in which the economists can plug in estimates from fishery biologists.


3. Controlled breeding — culling of young animals

It is the responsibility of the body in charge of a common pasture in the uplands to determine when the animals are driven to the uplands, and also how many, but each individual sheep farmer is responsible for limiting the breeding of his own sheep stock. Uncontrolled breeding would result in a greater increase in the stock than can be supported by the grazing. In the autumn, the sheep farmer must decide how many sheep are to live, and the slaughter of young animals is the most significant means of achieving balance. In this, the authorities are in charge of ensuring that the number of replacement lambs is not greater than can definitely be supported on the winter fodder available. In environmental affairs, it is generally considered that nature should enjoy the benefit of the doubt when considering the consequences of situations where the outcome is not certain. In the case of sheep farming, the animals enjoy the benefit of the doubt; if this were not the case, there would be the danger of their being undernourished. Only a fraction of those that are born in the spring are allowed to live through the following winter.

The point of view on which the rational control of cod fishing must be based is that normally there is only food supply to support a fraction of the numbers of young cod that are spawned. Most of the fry and small fish die for one reason or another, and one of these reasons is a shortage of food. The greater the role played by the shortage of food in this process, the greater the evidence of malnutrition perceived in the fish that it is planned to exploit. The rational control of cod fishing must aim at using fishing gear in such a way that enough small fish will be killed so as to ensure that hunger and malnutrition will not ruin the catch potential and that those that do reach maturity will enjoy comfortable conditions in which to develop from a young age until they are fully mature. If sufficient numbers of the stock are killed, the cod will enjoy the benefit of the doubt inasmuch as those that do live longer will not suffer from malnutrition.

It is the task for fishery biologists, through research, to quantify these conditions and give advice for the economists to put in their model.


FFblaðið (Torshavn) December 16 2004 24-25

(translated from the Norwegian, with small amendmends)



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