Without exception, existing data was such as to make impossible the use of global or structural models for estimating the state or potential of stocks. An effort still has to be made to improve the quality of catch and effort statistics, particularly for industrial fisheries. If CECAF standards are applied, the kind and quality of data they collect will mean that highly relevant scientific opinions can be formed. Given the importance of inshore artisanal fisheries, at least in certain countries, it would be desirable to improve the estimates of their overall catches, and assess the percentage, in number and weight, of the demersal portion of the catch.
Setting up a statistical data collection system so that more exact data can be had for assessment purposes being generally a slow process, especially in countries where research facilities are poor, the best thing would be to have at the same time recourse to more survey information - trawler and acoustic survey information - so as to directly assess how the changing pattern of the biomass is affected by fishing. Given the shortage of resources (vessels, people, funds) in each country, the promotion of this kind of research implies more intensive cooperation at the regional or subregional level. Concerning pelagic stocks the recent (November 1978 and March 1979) RV Capricorne surveys off Sierra Leone, Guinea and Guinea-Bissau offer a good example of what can be expected from a pooling of resources. On the operational level, preliminary exchanges of information on national programmes should make it easier to carry out joint activities.
A global approach to the productivity of the main ecosystems should prove particularly fruitful. Better use of existing data and knowledge (exploratory surveys, sediment charts, general knowledge of hydrology and ecology, such as the nature and distribution of communities) and the comparison of ecosystems which are rather well documented would likely make it possible to draw up productivity indexes including such factors as bottom type, hydro-climatic factors, sediments of land origin, intensity and duration of the upwelling, and so forth. Data from past exploratory surveys, especially the GTS survey and those done in Ghana in 1969-70, should be reviewed again in this new light. Sampling plans used up to now should be reviewed and perhaps improved. Very inshore ecosystems (0-10 m in coastal strip, mouths of mangrove-infested rivers) have never received special study and deserve special attention, especially in those countries where their contribution to fish production may well be considerable, as in Nigeria, Cameroon and Equatorial Guinea.
