Widespread concern has been expressed over the state of world fisheries resources. Garcia and Newton (1997) reported that nearly 70% of the worlds fisheries are either overexploited or nearly fully exploited. This serious state of affairs is the result of a growing world demand for fish, coupled with a fleet harvesting capacity that is increasing more rapidly than is the catch of fish. Gréboval and Munro (1999) have reported that from 1970 to 1990, world industrial fisheries harvesting capacity grew at a rate 8 times greater than the rate of growth of world catches. Milazzo (1996) reported that fishing fleets, taken on a global basis, have continued to grow while sustaining economic losses, and that such a situation could not have existed were it not for government subsidies to the fisheries. In a word, the worlds fishing fleets are larger than needed to harvest the sustainable catch, and unless this situation is addressed, the fisheries resources of the world will be further overfished. Capture quotas and fishing effort limitations can serve to slow this over-exploitation, but so long as fleets continue to grow, the probability of sustaining such measures will decrease. As fishing success for individual vessels continues to decrease, and subsidies continue to be given to the fishing industry, pressure to ignore or circumvent management measures will mount to the point that governments will find it difficult to support them.
These issues have been the subject of discussion among many governments and international organizations. At the Twenty first Session of the FAO Committee on Fisheries (COFI), held in Rome in 1995, it was noted that overexploitation, due primarily to excess capacity of fishing fleets, was threatening the sustainability of the living marine resources of the ocean. The meeting called on governments and international organizations dealing with fisheries to urgently review the capacity of fishing fleets under their jurisdiction and, where appropriate, to reduce that capacity.
Acting on the recommendation of the 1997 session of COFI, the FAO Fisheries Department convened a Technical Working Group on the Management of Fishing Capacity. This group met in La Jolla, California, on 15 - 18 April 1998 (FAO, 1998), and addressed the issues of how to define, measure, and control fishing capacity. Technical documents, prepared by invited experts, dealt with such questions as defining fishing capacity, determining the optimal capacity for any particular fishery, and deciding the objectives of a limited access programme. Following this action the Second Session of COFI, held in 1999, stressed the importance of holding a technical consultation to discuss the measurement of fishing capacity. As a result, a Technical Consultation on the Measurement of Fishing Capacity was held in Mexico City, on 29 November - 3 December 1999 (FAO, 2000). The objectives of the consultation were to review various issues related to the measurement of fishing capacity with a view to facilitating the monitoring and assessment of fishing capacity world-wide, and to advice on simple and practical methods for the measurement of fishing capacity and the assessment of any imbalance between actual and desired levels of capacity. Building on the work of the La Jolla Working Group, the Technical Consultation arrived at the following definitions:
Fishing capacity is the maximum amount of fish that can be produced over a period of time by a fishing fleet if fully utilized, given the biomass and age structure of the fish stock and the present state of the technology. Fishing capacity is the ability of a vessel or vessels to catch fish.
Target fishing capacity is the maximum amount of fish that can be produced over a period of time by a fishing fleet if fully utilized, while satisfying fishery management objectives designed to ensure sustainable fisheries.
Relative fishing capacity is the ratio between the current fishing capacity and the target capacity.
Furthering their earlier initiative to address the problem of excessive fishing capacity, the 1999 session of COFI adopted an International Plan of Action (IPOA) for the Management of Fishing Capacity, to be elaborated in the FAO Code of Conduct for Responsible Fishing. The objective of the IPOA is for states and regional fisheries organizations, to achieve worldwide an efficient, equitable, and transparent management of fishing capacity, preferably by 2003, but not later than 2005.
These actions are the first steps in clearing a path and setting a series of standards for the community of nations to undertake action to reverse the trends of a growing fishing fleet and expanding overexploitation of the seas living resources. Although not addressed specifically, tuna fisheries are no exception to these conditions of high demand, heavy exploitation, and growing capacity. Nearly all of the major tuna stocks of the world are fully exploited and some, such as Atlantic bluefin and southern bluefin, are severely overexploited (Deriso and Bayliff, 1991). The only region which might support a significant expansion of tuna fishing is the western and central Pacific (Klieber, Argue and Kearney, 1987). In other areas tuna fleets are apparently larger than needed to take the available harvest. In many of those areas where the stocks are fully exploited, the same amount of fish could most likely be harvested with smaller fleets, resulting in lower costs of production, greater economic returns, and on occasion lower prices for consumers. It seems clear that if there is to be rational management of the worlds tuna resources programmes to control the size of the global tuna fleet must be evaluated, and where necessary instituted.
However, because of the complex nature of world fisheries for tunas, it will be difficult to develop a system of controls and measures to which all nations will agree. Additionally, even though the Mexico City consultations arrived at a series of definitions of fishing capacity, consensus on these is so far lacking. Tuna fishing is prosecuted by a variety of vessel sizes and types, and unless output can be measured in economic terms it will be difficult to equate the output of one class of vessel with that of another. Also, about 80 nations are involved in tuna fishing, some catching tunas only in their coastal waters and others wherever tunas occur. However, the raw materials from these divergent fisheries enter a common market and derive from common stocks, which migrate over expansive areas of the worlds seas. The apparent objectives of many of these nations can be quite different as well. Some nations may wish to maximize employment, while others may wish to maximize economic returns. Many times these objectives can be confused or frustrated, particularly in those cases where foreign investors bring vessels under the flag of a coastal state, but few or none of the profits from such operations are kept in that coastal state. This complicates interpretation and application of economic models such as the Gordon-Schaefer model described by Greboval and Munro (1999), which state, as an objective, maintaining fishing capacity at the levels that will provide maximum economic rents. Finally, tuna fisheries are multi-species fisheries. Normally a single vessel will capture at least two species during a single trip, and many vessels capture up to three or four species during a trip. Frequently one of the species being captured is overexploited or fully exploited, while the other species are under exploited and capable of sustaining greater yields if greater fishing pressure is applied. Any programme to control fishing capacity must deal with all of these issues if it is to be acceptable and successful.
The purpose of this paper is to examine several of these problems. In doing so, trends in the production of tuna over the last several decades will be presented, and information on the status of the various stocks of tuna, where available, will be discussed. A discussion will also be given of the fleets that capture tuna, including the types of vessels and where available, some indication of their numbers.
For certain fisheries, where data are available, the relationship between production and capacity will be examined in order to identify situations that might indicate a need for capacity controls. Based on these results, a general discussion of what mechanisms might be available for designing such controls will follow. Finally, areas will be identified where data and information for examining the capacity problem is lacking, and recommendations made for filling those gaps.
There are of course, many approaches to managing fisheries such as catch quotas, closed areas and seasons, and restrictions on the types and amounts of fishing gear that can be employed to catch fish. Controlling capacity is only one means of managing fisheries, and it is this approach that will be the focus of this paper.