Artisanal Fisheries of the Chad Basin: The information-base.
(Percentage (%) of total publications)
GENERAL APPRAISALS (FISHERIES) (18%)
A broad base of information on the general status of the fisheries is available since 1900 ranging from accounts by early travellers to local and national government reports, and appraisal studies by international agencies (e.g. FAO). The latter have increased in recent years as development initiatives have proceeded. Common themes include the economic and social significance of the fisheries, the potential for development, the dynamic nature of production due to the natural hydrological cycle and climatic influences (e.g. Sahel drought), and management problems.
FISHERIES RESOURCES AND PRODUCTION (14%)
Fisheries resource assessment and production estimates are complicated by the poorly-understood dynamic and fluctuating nature of the water features in the Chad Basin. Best estimates of annual production by ORSTOM indicate that landings rose from 10,000t in 1960 to over 200,000t by 1974 as a result of the unregulated introduction of new technology (e.g. nylon nets) and an increase in effort, high levels of commercialization and the concentration of stocks in Lake Chad with the onset of drought. Post-1974 annual landings fell to 10,000–20,000t, although by 1987 with a rejuvenation of Lake Chad apparently underway, landings had probably increased. The maximum sustainable yield of “normal” Lake Chad is calculated to be 180,000t/yr. based on stock density estimates. Contemporary fisheries production in the Chad Basin has not been subject to any significant degree of management or regulation. Monitoring and formal fisheries statistics are almost non-existant.
FISH RESOURCE SURVEYS (3%)
The very limited numbers of surveys undertaken in both Lake Chad and major rivers indicate a high standing stock of fish which is multi-species in nature and subject to periodic variations in species composition and biomass due to the hydrological cycle. Fish resources of Lake Chad have been monitored continuously on a limited basis since 1960 by the Lake Chad Research Institute (Nigeria).
FISH BIOLOGY (27%)
Studies of fish biology account for the single largest number of publications on Chad Basin fisheries. However, of the 100 endemic species less than 10 have been studied in any great detail. The characin Alestes baremoze, one of the most abundant and commercially-important species, was studied intensively by the ORSTOM team based at N'Djamena in the 1970s and is best-known, to the extent of establishing models for production and population dynamics.
FISHERIES ECOLOGY (10%)
A number of detailed studies of Chad Basin fish communities were completed by the ORSTOM team at N'Djamena with special reference to trophic relationships, food types and energy flows. In addition, the cyclical migrations of fish between the floodplain, river and lake environments and the accompanying changes in population composition has has been well-documented. Special attention has also been given to the impact of the Sahel drought on the fish communities. Lacustrine species were replaced by swamp species as water levels fell and open water disappeared.
FISHING TECHNOLOGY (9%)
Early accounts detail the highly diverse forms of fishing gear and techniques used in the Chad Basin to exploit the wide range of habitats and the dynamic fish populations. However, by 1970, and in-part due to fisheries development initiatives, many of these traditional techniques had been replaced by nylon gillnets with an accompanying massive increase in fishing effort (600%). Traditional reed boats (kadei) have also been replaced by plank-built craft. Motorization, although promoted in the 1970s, has not been sustained due to breakdown problems and the high cost of spare parts.
FISH PROCESSING (9%)
Traditional methods of fish processing (e.g. sun-drying, smoking) have always predominated in the Chad Basin. However, it has been recognised that they are not entirely appropriate for treating the large volumes of fish now moved commercially; significant post-harvest losses have been incurred due to insect infestation and general decay. Although a number of detailed investigations, sponsored by the FAO, have identified the nature of the problem, attempts to introduce improved processing methods, including the use of salt, ice and a new design of smoking kiln, have had little impact.
FISH COMMERCE AND MARKETING (5%)
The provision of road infrastructure into the Chad Basin, coupled with the increasing demand for fish from urban southern Nigeria, has promoted a vigorous commercial trade in Chad Basin fish since the early 1960s. In the early 1970s, it was estimated that 50% of all fish landed was exported out of the region. The development of this trade has been documented in a number of detailed studies between 1960 and 1980 which involved the collection of significant quantities of primary data by Nigerian, FAO and ORSTOM workers. These data have also been used as indirect measure of fish landings during this period. Despite the impact of the Sahel drought on landings, the trade continues today and is likely to have a major impact on the future evolution of the fisheries.
FISHERIES ANTHROPOLOGY (1%)
The anthropology of fisheries production in the Chad Basin has barely received any attention. From the limited number of studies which have been undertaken and from general observations from many sources, it is clear that the ethnic composition and cultural characteristics of the indigenous peoples may be as diverse, dynamic and complex as the fisheries resources which they exploit. A greater understanding of the essential anthropological aspects of these peoples should be an essential component of any future multi-disciplinary study of the Chad Basin fisheries.
RESEARCH METHODOLOGY (4%)
Many workers have recognised the essential requirement for the development of specific methodology for use in studying the complex Chad Basin fisheries and have undertaken appropriate research. A primary focus has been the effectiveness of sampling fish populations in a dynamic and unpredictable aquatic environment. Other studies have addressed methods for analysing variation in catch data and the collection of statistics in general. Many of the studies (above) which have involved significant collection of primary data have incorporated an element of research into the methodology to be used. However, given the poorly-understood nature of tropical multi-species fisheries in general, there is much scope for further work on research methodologies.