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.