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Clearly, the most important question to pose in a study devoted to methods of controlling fishing effort is: why should fishery managers seek to control fishing effort at all?

Certainly the control of fishing effort is not a new phenomenon. Pearse (1980) indicates that trawling in France was controlled as early as the 17th century and most industrial fishing nations have a history of attempts at effort control. Depending on one's preference, the reasons for controlling fishing effort may be sought either in theory or practice or both.

Michael Graham in 1949 was one of the first people to examine both the empirical evidence and the underlying theoretical reasons for the need to control fishing effort. Since Graham many others, but most noticeably Hardin (1968), have considered the necessity for controlling access to commonly owned property.

The basic development of the economic ideas is due to Gordon (1954). Gordon's analysis depends on simple economic theory and predicts, in effect, that when a fishery is uncontrolled the following pattern of activity occurs. Initially, as the fishery develops, fishermen experience high catch rates on the abundant resources and make high profits. This attracts other fishermen into the industry and encourages those already there to increase their investment. Increasing fishing pressure then reduces the fish stock and increases competition amongst the fishermen for the dwindling resources. This reduces catch rates and hence profits to a level where the earnings merely cover the costs of the labour and capital employed, or, in the jargon of economics, to a level where the economic rent (value of landings minus costs of catching and delivering the fish) is completely dissipated.

This “open-access” result contrasts markedly from that which occurs where a fishery is the property of a sole owner (Scott, 1955). In this case the ability of the sole owner to collect a rent creates a significant incentive for the fish stocks to be husbanded for future as well as current use. It also leads to harvest of the resource at much lower cost.

Theoretically the steady state of an open-access fishery may or may not be at a level where the fish stock is below the level where it produces its Maximum Sustainable Yield (MSY). However, it is often the case in high value fish resources that this bio-economic equilibrium occurs at an effort level well above the MSY level, at a point where the resource is severely depleted.

This simple picture of the bio-economic equilibrium should not be viewed as providing an exact empirical description of events in a fishery. In a particular situation a number of complicating factors alter the details, if not the general picture of the open access fishery. Most importantly it should be recognized that both the fish stock and the fishery based on it will be subject to a number of exogenous factors. Those factors will tend to shift and alter the yield, revenue and cost curves, and a true deterministic equilibrium does not exist; indeed the concept of an equilibrium is best viewed in the real and stochastic world as a metaphor in which the long-term average behaviour of the system is described.

There are a number of economic disadvantages to a bio-economic equilibrium of this sort. The first and most obvious is that the fishing industry will be operating at a level of excessive costs and hence society will be failing to obtain the appropriate benefits from its fishery resource. An additional implication of Gordon's analysis has been highlighted by Clark (1977). Clark notes that as the industry tends towards the equilibrium the more efficient fishermen with high opportunity costs, i.e., the ability and opportunity to work elsewhere, will leave the industry. Those remaining will be the less efficient, who have little opportunity to work elsewhere. Doucet (1984) documents this problem for fishermen in the Bay of Fundy, and other examples may be found in a number of isolated fishing communities.

Apart from these economic disadavantages, there can also be major problems of conservation. In certain pelagic fisheries there is a tendency for catch rates to remain at a high level even though the fish stock is being reduced. The consequences of this increasing “catchability” with decreasing stock size are that severe over-exploitation of the fish stock may occur. Dramatic cases in point are the fisheries for the anchoveta off Peru and herring in the North Atlantic (Saetersdal, 1980; Ulltang, 1977; Butterworth, 1983; Troadec, Clark and Gulland, 1980).

It should be emphasized that conservation problems are not restricted to pelagic species, for the phenomenon of over-fishing, in a biological sense is ubiquitous.

For most species major declines in productivity have been produced when a reduction in the spawning stock has been associated with lower than normal recruitment. It is inappropriate in this document to deal with the stock and recruitment problem in any detail. Nevertheless, certain problems are worth highlighting. Firstly recruitment is highly variable (Hennemuth, Brown and Palmer, 1980) and although the variability differs significantly between groups (Beddington and Cooke, 1983) for most stocks it is largely unpredictable. The various models of stock-recruitment relationships from Ricker (1958) through to Shepherd (1982) add understanding of the possible patterns of recruitment, but are useless for predictive purposes (Garrod, 1983). The important point is that as stocks have been reduced there is a tendency for recruitment to decrease, although this decrease may be small for moderate levels of stock reduction. However, it is extremely difficult, due to the nature of fisheries' data, to fix on some stock level where significant change may be expected. Hence arbitrary assignment of some target escapement level (below which the stock should never be reduced) appears to be the most appropriate method of ensuring against poor recruitment.

The above ideas apply to separate stocks, but in some cases the productivity of whole communities can be reduced; for example, where a trawl fishery is capable of catching a whole selection of species from the fish community. Examples of such fisheries occur in the Gulf of Thailand, in the waters off Indonesia and Malaysia (Pauly, 1979a; Majid, 1984).

These considerations appear to suggest that the major problem is one of ensuring that the biological productivity of the resource remains high. However, it should be emphasized that a simple set of regulations aimed at ensuring the conservation of the biological stocks, even if successful, will not solve all the economic or social problems. In such situations, although catastrophic declines are now less likely to occur in the resource, nevertheless the open access character of the fishery means that the industry will tend to develop to a level where economic rent is dissipated and a catch is taken at a level of investment where the average level of profit in the industry is low.

In some sense this paper can be considered as a warning. For a number of the developed countries, many of the problems outlined above have already occurred. There is considerable over-capacity in the fishing industry, in the sense that the fishing power of the fleets far exceeds that required to take the typical catch levels. Furthermore many fish stocks are over-exploited, in the sense that their capacity to produce a sustainable yield has been substantially reduced.

One of the mistakes made in certain countries has been to treat these problems of the fishing industry with subsidies. Originally this was thought to be a simple and effective way of alleviating hardship in low income communities. It was not recognized that such subsidies have an unfortunate disturbing effect on the position of the bio-economic equilibrium. When the industry is benefitting from subsidies, the equilibrium occurs at greater levels of economic inefficiency, as subsidies often mean that capacity stays within rather than leaves the industry (Brochmann, 1984a).

It is sometimes claimed that, prior to the almost universal adoption of exclusive economic zones (EEZs), the pre-law of the sea conditions of open access were responsible for many of the problems of over-exploited fish stocks and over-capitalized industries. To some extent this is true, but it cannot be emphasized too strongly that such threats can also occur within individual nations' EEZs. This matter is reconsidered below, but it is useful to highlight one problem in this Introduction.

In the development of a fishery there is a major problem caused by the speed at which fishing capacity can increase. In the past this increase in capacity has often out-stripped the ability of the regulating authority to institute controls and the ability of the scientific community to assess the effect on the resource. Classic examples abound, but the anchovy fishery in Peru is probably the most well known (Glantz and Thompson, 1981).

With the adoption of EEZs, many countries have sought to develop their fishing industry with the help of bilateral assistance agencies, international development banks and other agencies. In principle such assistance is welcome, and properly applied, can be highly successful. Nevertheless, it should be noted that such programmes of development can aggravate the tendency for investment to outstrip monitoring and control capabilities. These matters are considered in more detail below.

A final problem of the bio-economic equilibrium, which occurs in the absence of regulation, concerns the competition between different sectors of the fishing community. In a situation of open access it can often be the case that capital-intensive vessels are at a competitive advantage; albeit that the overall level of economic rent is zero. With access controlled to the fishery, less capital-intensive vessels may well be more cost effective (Tillion, 1984).

Such problems are posed in dramatic form in the competition between industrial fisheries operating offshore with trawlers and artisanal fisheries restricted to the narrow coastal strip. These conflicts have resulted in dramatic fishery regulations: the banning of trawling in Indonesian waters is a recent example (Sardjono, 1980).

Having dealt with the whole set of problems that occur if fisheries are unregulated, it is clearly reasonable to ask: what are the solutions? A number of techniques of controlling fishing effort have been attempted, with varying success. In the remaining sections of this report these various techniques are considered and assessed. However, in order to assess the techniques, it is necessary to consider first the sorts of criteria that must be satisfied. This is dealt with in the next section.

Having reviewed the various techniques, and having dealt with the problems of assessment of the success, or failure, of different methods, in the final section we analyse the opportunities for controlling fishing effort in several major types of fishery.

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