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4.1 Historical perspective
4.2 Resource appraisals and fisheries potential

4.1 Historical perspective

The extended time series developed for the period 1950-1994 offer, for the first time, a comprehensive picture of the world fisheries over the last 45 years. Even though many of today’s fisheries have existed for centuries, they were largely undeveloped before this period, except in the North Atlantic and North Pacific. As a consequence, the new FAO time series describes the development of the world fisheries across the most important phase of their development and the changes in the level and composition of these landings help understanding some of the major characteristics of this development.

The data show the rapid increase in species diversity in reported national landings, particularly in the 1960s and 1970s, illustrating both the technological and geographical expansion of the fisheries and the increased value of some previously unspecified species on the market. The landings have increased more or less regularly, with some oscillations as expansion proceeded, but the analysis of the species composition shows that the world landings increase has been sustained by successive exploitation of new clusters of species-area combinations.

A major source of variation in fish supply from 1950 to 1994 is accounted for by a few species. It is suggested that aggregate landings of pelagic and demersal marine fish are useful indicators of overall trends in world fisheries once a few top species, which account for a disproportionately high share of the total variation, are excluded. These indicators show a continuous increase in the underlying trend in pelagic landings in contrast to that for demersal fish which has remained level since the early 1970s.

The analysis of the ratio between the landings of pelagic and demersal species has revealed interesting differences between oceans which may relate to their hydrographic conditions. The proportion of pelagics has remained stable for the Atlantic (around 50% of fish landings) and the Indian Ocean which appears to show a “deficit” in pelagics (around 45%); it oscillates strongly (around 59%) for the Pacific; and has significantly increased since the 1950s in the Mediterranean (declining sharply with the collapse of the Black Sea resources).

The landings data also reflect the spread of fisheries development from the Atlantic Ocean (in the 1960s) to the Pacific and Indian Oceans (in the 1970s and 1980s). They also show the declines in yield from the overexploited species, mainly in the Atlantic, and while environmental influences may also have had a negative impact on some of the overexploited stocks, effective management would undoubtedly lead to increases in yield. This has been demonstrated for the Northeast Arctic cod stock in the Norwegian and Barents Seas which, in contrast to most other Atlantic cod stocks, has shown a recovery in spawning stock biomass from a depleted condition to a level not seen since the 1950s following a major reduction in fishing mortality in the late 1980s (ICES 1995).

The landings from distant waters, which increased exponentially in the 1960s, but fell abruptly in 1973 with a drop in Alaska pollock catches. Further development was curtailed by the rapid increase in the number of countries which claimed extension of their national jurisdiction, as well as the increase in the price of fuel oils after the first and second oil crises in the 1970s. Distant water fishery landings declined dramatically in the 1990s with the collapse of state-owned (and heavily subsidised) fleets of Eastern Europe.

Although landings of straddling stocks have declined since the late 1980s, landings of the highly valuable highly migratory species continue to increase and several countries such as China are increasing fishing effort on these species.

A large proportion of the landings of the highly variable small pelagic species are reduced to fish meal and oil and it has often been stated that a good proportion of these landings could be diverted to food use. However, our analysis of fish utilisation and trade since 1961 and the relationship between the supply and price of fish meal, provides evidence of the progressive emergence of a proper market for fish meal, independent from the market for soybean meal to which it was originally strongly related. The impacts of this emergence and the role of aquaculture on the evolution of the market are not yet fully understood but they offer both room for hope and for concern, particularly for the food supply to the poorest populations.

The existing difficulties in utilising many small pelagic species for human food (cost of proper catching, handling and storage methods; large fluctuations in abundance affecting price stability) may be compounded by increasing competition from the fish meal market due to increasing demands from the aquaculture industry for the production of carnivore fish and shrimps for the high value markets, although this might be offset, at least partially, by some agricultural markets shifting away from fish meal (Ian H. Pike, pers. comm.). The reduction to fish meal might still be mainly operating on the surplus production of small pelagic fish, regulating indirectly the supply to the food market of the species also used for human consumption. However, if the trend of rising price for fish meal continues, the fish meal market may start “biting” on the food supply of the poorest people.

4.2 Resource appraisals and fisheries potential

The overall picture which emerges of the current state of world fisheries is consistent with what FAO has already stated in its last world review of the state of marine fisheries but, with due consideration to the numerous caveats, it differs with regard to fisheries potential. It is recognised that the type of global assessments made here cannot be as accurate as those conducted stock-by-stock using traditional stock-assessment methods. We are convinced, however, that these detailed analyses are often too fragmented to help obtaining a coherent overall picture (“the trees hide the forest”), and that a combination of analyses at both broad scale and stock level is desirable. The present analysis could therefore be used as a backdrop to the more detailed studies and reviews undertaken by FAO, area-by-area and stock-by-stock. Because of the weak statistical basis of the analyses (due to the high variability in the data), the conclusions offered should be considered as tentative and as reflecting the limited state of our current understanding, rather than as a definite statement.

Resource assessments

This analysis has described the dynamics of fisheries on the 200 top “resources” of the world and lead to the conclusion that, in 1994, about 35% of them were in the “senescent” phase (with declining landings), 25% more were in the “mature” phase at a high exploitation level, and 40% were still “developing”, while there were none remaining in the “undeveloped” phase11. The analysis of the shape of the development trajectory of the different clusters of species supporting the world fishery clearly demonstrate the rapid increase in fishing pressure on the top 200 resources of the world, the result of which is a gradual increase of the estimated number of stocks requiring management from almost none in 1950 to over 60% in 1994.

11 We are talking here of “conventional” resources as no time series of data exist for the analysis of the state of non-conventional resources such as krill, mesopelagic fish, and many oceanic squids which are usually considered under-developed.
This underlines the urgent need for effective measures to control and reduce fishing capacity and effort. A strikingly similar conclusion was reached by Garcia and Newton (1994) based on traditional stock-assessment information regularly compiled by FAO. Using a global production model, with estimates of the world capacity as a measure of fishing pressure, those authors concluded that the demersal high value species were overfished and that a reduction of at least 30% of fishing effort was required to rebuild the resources. It was also concluded that globally, when all demersal and pelagic resources were pooled together, the world fishery seemed to be operating close to it level of maximum production. This conclusion is identical to the one reached here when the fishery development model is applied to the world time series of landings.

Fisheries potential

Generally speaking, the Indian Ocean has the least developed fisheries, but nevertheless, the coastal resources in this Ocean are under severe stress in many areas and require effective management, even though potential for expansion may exist further offshore. It must also be pointed out that although the possibility of expanding Indian Ocean fisheries offshore has been repeatedly considered by the coastal countries in that area, particularly India, Indonesia, Malaysia and Thailand, no convincing evidence of the existence of such resources has ever been provided.

It is interesting to note that the estimates of the possible gains to be obtained through management or development depend on the level of aggregation in the analysis. The more aggregated the data used for the analyses, the less is the estimated potential for further increase. This is an expected result as only a disaggregation of the time series by region and stock can reveal the various situations of under-development or overfishing that exist contemporaneously in all areas. This analysis of regional resources takes the disaggregation only some way towards the stock level of detail.

(1) When the world marine landings aggregates are analysed using the fishery development model, the world resources appear fully exploited at present levels of exploitation and little may be expected beyond recent level of production which averaged 83 million tonnes in 1990-94.

(2) When the data are disaggregated by oceans before applying the same model, the relationships are statistically weaker, and as expected, the different oceans appear at different stages of fisheries development, with the sum of the results indicating a total potential of about 100 million tonnes (identical to the potential calculated by Gulland (1971)), representing a potential gain from the present of about 17 million tonnes predicted as coming mainly from the development of Indian Ocean fisheries.

(3) When the data are disaggregated further, by FAO major fishing areas, and the same model applied, the relationships are generally even weaker and the regions appear at different levels of exploitation and with different potentials. The sum of the results indicates a potential of about 125 million tonnes, with a potential gain of about 40 million tonnes on recent landings, partly from management and partly from development. Some of this additional potential is attributable to marine aquaculture production (mainly crustaceans and molluscs) as this production was included in the data. Mariculture accounted for only 6 million tonnes in 1994 but it is growing rapidly. The comparison of potentials by unit area across regions gives unsatisfactory results. This is to be expected considering the inherent differences in productivity one can expect between temperate and tropical areas, or between ocean upwelling-driven fisheries (dominated by small pelagics) and tropical river-driven shelf fisheries (dominated by demersal species). A more detailed analysis by FAO major fishing areas or other finer stratification will be needed before the results obtained at the highly disaggregated level can be accepted.

The statements made in the various sections of the paper which have implications in terms of resource assessment or fisheries outlook are summarised in Table 9. Taking all the results together, it seems reasonable to reject the assessment of world marine fishery potential based on the time series of world total landings which leads to an estimate of 82 million tonnes. The reason is that a number of more detailed analyses have shown the opposite:
(1) The analysis of the overexploited marine resources has shown that there may have been historical “losses” (of about 9 million tonnes) due to overfishing which might be recouped through management. The existence of such “losses” is supported by the analysis of the demersal fish resources (5 million tonnes loss) and of the straddling stocks (2 million tonnes loss), although there is much overlap in the composition of these classifications. The landings from distant waters have decreased by 4 million tonnes, mainly as a result of reduction of effort. Anyway, distant water fishery “losses” are probably already included in the straddling stocks losses, and so cannot be added. However, the global figure of 9 million tonnes from improvement of management of overexploited resources may be considered a minimum, assuming the degradation of the resources is reversible.

(2) In addition, the resources evaluation based on clustered groups of resources has estimated that fisheries on 40% of the major marine fish resources are still developing. Garcia and Newton (1994) had estimated that fisheries on 31% of the stocks for which assessments where available where still developing and 3% recovering. The analyses of the relative rate of increase in landings indicate that in 56% of the areas the point where the rate of increase is equal to zero has been passed (denoted “O” for “overfished” on Table 6) while 38% are still increasing. These results clearly indicate that in some areas and on some resources, an increase in landings is still possible, even though the magnitude of this increase is not known.

Table 9: Summary of analyses, conclusions and diagnostics.

Type of analysis



Trends in demersal fish

· Overall decrease

· Production stable since the 1970s

· Hiding overfishing

· Sum of peaks minus present landings

· In 31% of the FAO areas: increases

· Largely due to overfishing

· In 67% of the FAO areas: decreases

· Possible increase unknown

· Minus 5 million tonnes

· Obtainable through management?

Trends in overexploited marine resources

· Overall decrease

· Minus 6 million tonnes since 1985

· Overfishing

· Sum of peaks minus present landings

· Minus 9 million tonnes overall

· Overfishing

Trends in highly migratory & straddling resources

· Highly migratory

· Still increasing

· Some overfished

· Straddling

· Minus 2 million tonnes since 1989

· Mainly overfishing of Alaska Pollock

Trends in distant water fishery resources

· Overall decrease

· Minus 4 million tonnes since 1990

· Resources & socio-economic problems

Trends in 200 major fish resources (accounting for 77% of world marine fish landings)

· 35% resources overfished

· 60% need urgent management

· 25% resources fully fished

· 40% still developing

Assessed state of stocks in 1992 (Garcia & Newton, 1994)

· 31% stocks developing

· 69% need urgent management

· 22% stocks overfished

· 44% stocks fully fished

· 3% stocks slowly recovering

Trends by ocean

Possible additional production

· Atlantic

· Fully fished in 1980 (21.106 t.)

· No further increase

· Pacific

· Fully fished in 1999 (54.106 t.)

· Insignificant increase (+ 1.106 t.) through development

· Indian

· Developing (5.4%/year, 23.106 t.?)

· Substantial increase (+ 16.106 t.) through development to be verified

· Mediterranean & Black Sea

· Developing (2.6%/year) (2.106 t.)

· Increase through eutrophication (likelihood unknown?)

· Three estimates of global marine potential:

World Ocean

· Fully fished in 1996 (82.106 t.)

· Further increase unlikely

Sum of oceans

· Developing (100.106 t.)

· Substantial increase (+ 17.106 t.) depends on reliability of Indian Ocean estimate. Mainly development.

Sum of areas

· Developing (125.106 t.)

· Very substantial increase (+ 42.106)t mainly from management and development. Highly unreliable.

Having established that, despite the conclusions of the global assessment, the present landings could probably be increased by about 9 million tonnes from management plus some unknown quantities from further development (including in the Indian Ocean), what are the further elements available to bound the estimate of potential for increase of marine harvest? The analysis by major fishing area indicates (with many more doubts as to the statistical reliability) a more diversified situation and a potential overall gain of 42 million tonnes. Such gains would come from (see Table 6):

(1) Management of fisheries of the Atlantic for about 6 million tonnes (or 14% of total gain), mainly from the Northeast, Northwest, Southeast, and Eastern Central areas;

(2) Management of fisheries of the Pacific for 2 million tonnes (or 5%), mainly from the Northeast and Eastern Central areas;

(3) Development of fisheries of the Eastern and Western Indian Ocean, for 16 million tonnes (or 37%);

(4) Development of fisheries of the Pacific for 19 million tonnes (or 44%).

These last two potential sources of landings are not well founded statistically and are the most doubtful.

Mariculture production is included in the data used in both the global and regional assessments. It will have a negligible influence on marine fish projections (diadromous fish such as salmon are not included in the analysis) but it is important for crustaceans and molluscs. The great variations in the importance of aquaculture among regions (which are masked in the global analysis) may explain some of the differences between the global and regional projections.

Implications for management and development

The improvement in world supplies may come from improved management, from development of the few remaining under-exploited resources, and from mariculture. For the resources which are presently below their historical peak levels of production, it might be possible to return to these levels, by reducing fishing effort and, in most cases, simultaneously improving yield-per-recruit. This can be achieved by increasing significantly the age at first capture, prohibiting the exploitation of juveniles, increasing mesh sizes, and closing temporarily or permanently areas of concentrations of young fish. Examples in Cyprus and the Philippines (Garcia 1986) have shown that increases of sustainable production of 100% can be obtained in the tropics within 18 months. More recent experiences with the protection of juveniles in Morocco (on cephalopods, through a closed season-area) and Norway (on cod, through ad-hoc area closures) have also produced dramatic and rapid improvements in catch rates which tend to show that short-term benefits can also be expected in more temperate areas.

An important problem and opportunity is in the potential improvement from the reduction of unwanted bycatch. It has been estimated that 27 million tonnes of fish are discarded every year (Alverson et al., 1994), composed of species of low commercial value but also of a large proportion of juveniles. These 27 million tonnes are part of the catches, if not part of the landings, and do not appear in the data used in this study. If added to the present landings, they result in a world marine catch of more than 110 million tonnes. The benefits resulting from a reduction of unwanted bycatch through increased survival of juvenile fish can be very significant.

Increases in production would come from further fisheries expansion on those resources which are apparently still increasing their contribution to world landings (about 40% of major fish resources are classified as still “developing” in this study and Garcia and Newton (1994) estimated 32%). It must be recognised that for these resources, landings are still growing at a steady rate, it is not possible to have a reliable estimate of the potential. It would be a mistake, however, not to recognise that this potential exists.

An important question is whether, at the global level at which the analysis has been conducted, improvements in yield from both demersal predators and pelagic prey can be expected. The pelagic group contains a number of significant predators, among which are the large pelagic tunas and tuna-like species. The demersal group contains a number of small species which are prey and demersal fish eggs and larvae, during their early pelagic phases, are prey for the small pelagic species. The implications of this “looped” relationship are not easy to foresee and it is therefore impossible to establish how much of the present balance in the abundance (and potential) of pelagics and demersals results from the relative overfishing of the demersals and the resultant reduced pressure on pelagics. Neither is it possible to determine to what extent the rehabilitation of the overfished demersals will affect the survival and potential of the pelagics. The issue of resources rehabilitation at large regional scale (i.e. within a Large Scale Marine Ecosystem, LME) has never been tackled and remains, with the issue of the medium-term variations of the small pelagics, one of the key issue of the management of fisheries for the 21st century.

In conclusion, while it must be recognised that the statistical significance of the most detailed analysis in this paper is insufficient, the elements of information available indicate that an improvement of fisheries production through management is possible (about 9 million tonnes) and further increase landings can be obtained from fisheries development, of unknown magnitude, as well as from mariculture. A maximum of 42 additional million tonnes has been estimated. FAO (1995c) had indicated that 20 million tonnes more of landings might be obtainable, but this was made without a solid analytical foundation. This work indicates that there may be valid reasons to expect such an increase to be realised if: (a) degraded resources are rehabilitated, (2) under-developed resources are exploited further, avoiding, however, their overfishing and avoiding the overfishing of those resources which have already reached the highest level of sustainable exploitation they can stand, and (3) discarding and wastage is reduced.

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