Рыболовство во внутренних водоемах

Small pelagic fishes and fisheries in African inland waters. CIFA Technical Paper No. 14.

Overview of inland fisheries

This is a brief review of small pelagic fishes and fisheries of Africa's large lakes and reservoirs. Small pelagic fishes have an important role to play in increasing Africa's inland water fish supply because the available potential generally has been underutilized. Pelagic communities in African inland waters usually consist of small zooplanktivorous species and a group of predators which feed upon them. In addition to being small these prey fishes usually have a short life-cycle and high productive potential. There are four major families which include pelagic species with actual or potential fishery importance in Africa. The general biological characteristics of these species are discussed and the major pelagic fisheries in Africa are described.

Productive inland fisheries based on small fish are found in various parts of the world. A well-known example is the fishery for the small cyprinid Mirogrex terrasanctae on Lake Kinneret which dates from biblical times. Another interesting example is from the Philippines where highly productive fisheries were based on the goby Mistichthys luzonensis which, at 12.5 mm mean length, is the smallest commercially exploited fish.

Small fish have not been intensively exploited in African waters although there are some traditional fisheries which utilize them. The long-established one based on the Lake Tanganyika clupeids is well-known and Poll's description of it as “de quelque sorte le sport national des indigènes du Tanganyika” suggests that is played an important social as well as economic role. Clupeids were also taken in the West African rivers, as in the “Atalla” fishery of the lower Niger. In Lake Chilwa, the small cyprinid Barbus paudinosus was a major component of the fishery and Barbus spp. are regularly exploited in African rivers.

There has been a recent upsurge of interest in the small pelagic fish of African lakes and their commercial value is becoming more apparent. There appears to be two main reasons for this. The first is that the rapid growth of Africa's human population has led to increased exploitation of many inshore fish stocks. In Lake Victoria, for example, the tilapia stocks were thought to have been over-exploited as early as 1960 and increased fishing pressure since then has left the pelagic stocks, mainly the cyprinid Rastrineobola (Engraulicypris) argentea, as the only possible avenue for fisheries expansion apart from Haplochromis.

The second factor is the considerable increase in surface water resources brought about by the construction of several large reservoirs during the last three decades. In some of these, productivity was depressed because no indigenous fish could colonize their pelagic waters. Pelagic fish of the great lakes seemed to be good candidates for introduction into these lakes and the success of the Tanganyika sardine Limnothrissa miodon in Lake Kariba showed the possibilities of translocating and commercially fishing such species. The establishment of such fisheries might compensate local populations, to some extent, for the loss of traditional homes and other social problems caused by large reservoirs.