The lake is known internationally for the spectacular variety of its endemic cichlid fish fauna. It is composed of a remarkable and genetically-diverse demersal community with a contrastingly simple pelagic community. The demersal community includes almost 300 fish species of which over two-thirds are endemic. The pelagic fish community is composed of six endemic, non-cichlid species (see Fig. 1): two schooling clupeids, Limnothrissa miodon (Boulenger, 1906) and Stolothrissa tanganicae (Regan, 1917), and their major predators, four members of the genus Lates (Centropomidae), L. stappersii (Boulenger, 1914), L. angustifrons (Boulenger, 1906), L. mariae (Steindachner, 1909), and L. microlepis (Boulenger, 1898).
Most fishing is done at night as virtually all fishing methods (e.g. purse seines, lift-nets, beach seines and scoop-nets) rely on clupeids being attracted to light. Fishing activities, therefore, practically cease every month during the full moon. There are three recognizable types of fisheries on Lake Tanganyika, as described below.
Fishing effort and catch
- The semi-industrial fishery was started in 1954, when Greek fishermen introduced the purse seine. A typical industrial fishing unit consists of 16 to 20 m long steel vessel, a purse seine and auxiliary steel boat, 5 lamp boats and a total crew of 30-40 fishers.
- The artisanal fishery in the northern part of the lake uses mainly catamarans, 'Apollos' and to a lesser extent trimarans, although the latter have totally disappeared from Burundi. A typical catamaran fishing unit consists of two (three for trimarans) 6-7 m long mainly wooden plank hulls, a lift net (55 - 65 m circumference), 6-7 lamps and an average of 4.7 fishers. 'Apollo' is a large catamaran: 7-9 m long canoe, lift-net of up to 100 m of opening circumference, 14-19 lamps and an average of 8-11 fishers. There are very few catamarans in the Zambian part of the lake; the majority of artisanal fishing units in the south are beach seines operating at night, with lights, mainly to catch clupeids. A few 'chiromila' (boat seine) units are also active in these waters.
- The traditional/subsistence fishery uses many different fishing gears (gill-nets, hook and line, scoop-net, longlines, traps, mosquito-nets, etc.). Although these gear are generally less efficient than artisanal gear, many people are involved in their use around the lake.
A major decline of the catch per-unit-unit-effort (CPUE) has been recorded over the last ten years for the semi-industrial as well as the traditional fisheries within Burundi waters. The average CPUE/night for the semi-industrial fishery in Burundi decreased from 1173 kg/night/unit in 1983 to 150 kg/night/unit in 1993 and now appears to be unprofitable. However, the artisanal lift-net fishery, due to the use of bigger nets, better fishing lamps and the choice of more productive fishing grounds, manages to maintain its CPUE at a profitable level. For example, the CPUE for 'Apollos' was 300 kg/night/unit in 1993. [ see table ]
The lake's commercial fishery in recent years is essentially based on the two clupeids (ca. 65% by weight) and L. stappersii (ca. 30% by weight). Clupeids are generally the most abundant species, although there is often an inverse relationship in catch numbers between clupeids and L. stappersii. The total fish catch for Lake Tanganyika for 1995 was estimated at 178 700 mt, shared as follows: Burundi 21 000 mt, Tanzania 55 000 mt, DRC 90 000 mt and Zambia 12 700 mt. The value of the catch has been estimated at approximately $US26 million.
Over one million people are dependent on the Lake Tanganyika fisheries including almost 45,000 fishers and their families and those involved in fish processing and marketing.
Considerable differences exist in the level of post-harvest fisheries development around the lake. There is an extensive and costly infrastructure (cold stores, processing plants, refrigerated trucks, etc,) in Mpulungu, Zambia, and to a lesser extent in Kalemie, DRC. No such facilities are available elsewhere, notably in Bujumbura and Kigoma.
Clupeids and juvenile L. stappersii are either sold fresh or sun-dried at most local landing sites. Adult L. stappersii and other larger fish are sometimes smoke-dried by local processors before sale. Improved methods of brine washing and rack drying have been introduced but are rarely used. Energy-intensive industrial techniques of cleaning, brining, freezing, and (sometimes) smoking are practised only at processing plants in Mpulungu and in Kalemie. Recently, the canning of clupeids and L. stappersii was developed in Zambia. External marketing of catches in excess of local needs is difficult and complex due to transportation problems. With the exception of the very north of the lake, most roads are tangential. The shores are steep and few roads link the populations around the edges of the lake, particularly the extensive shorelines of DRC and Tanzania. Fish, particularly clupeids, are thus traded along the coast by 'water-taxis' or by the ferries M/V Liemba and M/V Mwongozo at ports between Mpulungu and Bujumbura. Major outlets for dry fish are the 'Copperbelt' complex of large towns in Zambia, the DRC cities of Lubumbashi, Bukavu and Goma, and in Rwanda.