Many tuna stocks in temperate or tropical waters are under heavy pressure. Biological overfishing has often been avoided because of economic constraints and by transferring excess effort to the surface on younger age classes, farther offshore on domes and fronts and to other areas and oceans. Overfishing could not be avoided, however, for long-lived highly valued tunas (bluefin in particular) and significant improvement of management is required for this species. The Southern Ocean may be the next and last possible geographical extension of tuna fisheries (on Allothunnus fallai) and higher catches are still possible on yellowfin and skipjack. The problem of effort control, already important in some areas and for some species (e.g. bluefin), may rapidly generalize if fishing pressure grows in response to increased size and demand of the world population.
With the emergence of the dolphin problem, tuna fisheries development is facing new constraints. Competition between traditional tuna fishing powers and emerging tuna industry in developing countries22 is increasing and the control of international effort levels may become a major problem. In the absence of explicit considerations of “equitable” allocation of resources, conflicts are bound to increase. These may lead to a re-opening of the question of the “highly migratory” status of tunas and on the rights and responsibility of coastal countries in managing these species in their EEZs.
The information on oceanic sharks is very scanty and these resources may offer more potential for immediate concern regarding their sustainable development than potential for increased production and better cooperative research is badly needed. The same can probably be said about marine turtles.
The migratory behaviour of the highly migratory species listed in the 1982 Convention is variable and the grouping looks heterogenous and perhaps even arbitrary. There are other high seas resources of similar behaviour which do not appear in that list, including some tunas and many important tuna-like species. Their situation remains therefore obscure as far as management is concerned. From a scientific and technical fisheries management perspective, it would be desirable to explore the possibility of reaching an understanding on the operational definition of the concept of highly migratory species, or to consider whether the list of highly migratory species in Annex I of the 1982 Convention could be somehow revised and updated in order to clarify exactly what are highly migratory species as opposed to straddling stocks.
Many demersal resources extending on high seas shelves (i.e., conventional straddling stocks) are fully fished if not overfished and in some cases have led to political friction (e.g., Grand Banks cod, Alaska pollock, Chilean horse mackerel). Large pelagic species (some of which are highly migratory in the sense of the 1982 Convention) represent important “straddling resources” for island countries. Progress in net-making technology should facilitate the intensification of the exploitation by island countries of some of these species, such as dolphinfish, flying fish, as well as large tuna-like species presently assumed underexploited with unknown potential. However, problems of accidental capture of low-resilience and ecologically sensitive species could emerge (e.g., with small cetaceans, turtles, etc.).
Demersal high-value straddling resources have suffered from overfishing. The situation is unlikely to improve unless innovative solutions are found and political resistance is overcome to put in place systems to collect data, promote collaborative stock assessment, elaborate and enforce management measures at international level. Limitations on removals through effort controls are required and, in some cases, sophisticated management schemes may be needed to deal with sequential fisheries. The situation in this respect looks only superficially better in the case of highly migratory stocks. Among the major issues and problems that impeded the establishment of responsible fisheries in the high seas the following are still awaiting a negotiated solution:
Improve cooperation for the compilation of reliable data, stock assessment and management on the whole distribution range of the resources.
Improve State control on their fishing vessels to operate on the high seas and regulate reflagging.
Improve enforcement capacity of regional arrangements.
Address effectively the issue the regulation of effort (effort limitations, TACs and quotas) and resources allocation.
Define the potential role of market regulations in management of multispecies and ecosystems.
Analyse the potential role and agree on possible ways of implementing cautious management approaches compatible with sustainable fisheries development.
Most of these issues will have to be addressed if the Agenda 21 Programme adopted by UNCED for the high seas has to be implemented and FAO will contribute to the process through the development of a Code of Conduct for Responsible Fisheries.
