FAO has regularly published descriptions of trends in fisheries based on computerised statistics available since 1961 at the earliest. Recently, the statistics of world fishery landings as published in the FAO Yearbook of Fishery Statistics - Catches and Landings for the period 1950-1969 have been completely revised to include estimates of missing data, to disaggregate landings by fishing areas and to take account of political and other changes during this period. As a consequence, the time series in the database have been extended backwards by 20 years so that the period covered in computerised form is now 1950-1994. These landing statistics are based on reports from national authorities, supplemented with statistics from regional fishery organisations and other sources. Where data were missing or were considered unreliable, FAO included estimates based on the best available information from any source such as project documents, industry newspapers, or in the worst case, repeated figures from another year.
The extended time series describe landings from capture fisheries and aquaculture production for fish, amphibians, turtles, crustaceans, molluscs, tunicates, arachnoids, echinoderms and other aquatic invertebrate species, both inland and marine, and were first presented in a publication containing a graphical summary and the data set summarised by species groups on diskette (FAO 1995a). World production of these species has increased from about 20 million tonnes in 1950 to about 110 million tonnes in 19942. This is a measure of the vast bulk of aquatic production (in live weight) used for human food and animal feeds, and does not include production of aquatic mammals, crocodiles and alligators, pearls, mother-of-pearl, shells, corals, sponges and aquatic plants, much of which does not go for food and feed uses. Statistics for 1950-1969 for this latter group of species and products are still being reworked and will be disseminated later. The extended time series include data for 1047 species items, 247 countries and 28 fishing areas.
2 Discards, estimated for the recent years at about 27 million tonnes, not includedThe first estimates of world fishery production were provided in 1945 by the Technical Committee for Fisheries of the United Nations Interim Commission on Food and Agriculture (FAO 1945) and these indicated that the total marine harvest was 39,000 million pounds (or 17.7 million tonnes), of which 37,000 million pounds was commercial landings and the remainder subsistence and recreational landings. Even then, one third of the total landings were destined for reduction to fish meal and oil. At that time only the North Pacific and North Atlantic fisheries were well developed and these areas accounted for 47% and 46% of the total commercial harvest, respectively, with the southern parts of those Oceans accounting for 1% each and the Indian Ocean for 5%. The same report stated that there were considerable possibilities for fisheries expansion, mainly off Central America, off Peru and Chile, in the Caribbean, off west Africa and off Australia, New Zealand, the South Pacific Islands and the East Indies. It recognised, however, that some stocks were already overfished and pleaded that the benefits of stock recovery in European waters during the Second World War should not be lost once normal fishing activity resumed. It stressed the essential need for fisheries conservation based on scientific evidence, particularly at a regional level, and recommended that FAO promote the collection of basic fishery data and analysis of them.
In the 50 years since that report was prepared, fisheries have developed rapidly with the result that there are now few underexploited resources and an increasing number of overexploited ones (see below). The challenge of implementing effective management has proved much more difficult than the authors of the report could have expected.
Not since Gullands (1971) analysis has there been an estimation of the fishery potential of the oceans based on historical landings data, and given that Gulland was using FAO landing statistics for 1953-1968 (less than half the time period currently available), it is appropriate to review estimates of potential in light of the major developments which have taken place since. During the period for which Gulland had data, landings were increasing at about 6% per year (Figure 1), and Gulland estimated that the potential for traditional marine fish species was about 100 million tonnes per year. This estimate of fishery potential was consistent with estimates made earlier by several other authors (Moiseev 1969, p. 203), most based on less rigorous analyses than those of Gulland. In fact the growth rate for marine production observed by Gulland soon fell, although some growth was maintained, and despite fisheries developing on non-traditional species, the marine fishery production has so far only reached about 90 million tonnes with capture fisheries accounting for 84 million tonnes (Figure 2).
Figure 1. Trends in world marine fish landings in relation to potential (logarithmic scale) (Gulland, 1971, Figure SI with data updated)
Figure 2. World inland and marine fishery production from capture fisheries and aquaculture
An early study of the patterns in long-term landings from fish stocks was made by Caddy and Gulland (1983) who classified stocks into four categories in order to help refine approaches to developing and managing fisheries by taking into account the consequences of different degrees of departure from the steady state hypothesis. Once stocks are classified according to their productivity patterns, the next aspect to consider is how such patterns might be responses to fishing pressure. For this purpose Caddy (1984) described an idealised fisheries cycle comprising four phases of fishery development.
This paper presents an initial analysis of trends in marine resources as described in the extended data set which covers the period of the greatest expansion of world fisheries. By grouping resources according to the pattern of their landings, relating the patterns to Caddys (1984) phases of fishery development, and estimating fisheries potential based the relative rate of growth in landings, we attempt to demonstrate that, despite the errors that undoubtedly exist in national statistics and the high level of aggregation (i.e. by 19 marine major fishing areas), the extended data set provides a surprisingly coherent and potentially useful description of the developments in the worlds fisheries at global and regional levels which can assist the appraisal of fisheries potential and so aid planning and policy-making for the future.