SCIENCE@home

Freshwater small pelagic fish and their fisheries in the major African lakes and reservoirs in relation to food security and nutrition

J. Kolding

Published 2019 in Unknown venue

ABSTRACT

The recorded catches of most of the larger commercial fish species in Africa, such as large breams (Cichlidae), carps (Cyprinidae) and perches (Perciformes), which have been the focus of fisheries management, have not changed greatly over the past three decades. In contrast, the landings of small species of herring (Clupeidae), carp, bream and characin species – mostly zooplankton feeders, predominantly living in open waters of African lakes and reservoirs – in short, “small pelagic fish”– have steadily increased. These fisheries have developed in addition to the fishing of, and sometimes as a reaction to, decreased catch rates of larger species, introductions and the creation of large water bodies such as reservoirs. They now represent nearly three quarters of the total inland fish catch of the African continent, although there are known difficulties in obtaining accurate inland fishery catch statistics. Despite limited stock assessments, there are no clear examples of a small pelagic fishery being overfished. The expansion, technical development and marketing of these fisheries have nearly all been achieved by a multitude of local stakeholders with very limited scientific monitoring or management. Even though small pelagic fish species, and small fish in general, have always been part of the catch of subsistence fisheries in the large water bodies of Africa, they have conventionally been regarded by fisheries managers as resources with “low economic value” and consequently have been afforded low priority with respect to research and monitoring. As a result, there are still major gaps in our biological knowledge and understanding of the full potential of many species. Common to all, however, is their small size and corresponding high turnover rate, with most species being able to reproduce their own biomass around five times or more per year, which is at least twice the rate of the larger commercial species. This unparalleled level of production, together with the relatively simple technologies used for their capture, the reduced availability of bigger species because of heavy exploitation and an increased demand for fish, are the main reasons for the considerable increase in fishing effort on smaller species that has been observed in African inland fisheries over the past three decades. Nevertheless, due to the small size of these species and the corresponding necessity of using fishing gear with small mesh sizes, many of the fisheries are operating within the constraints of the current fisheries legislation, which is largely aimed at protecting juveniles of the larger species. Many of the capture techniques may therefore be illegal and this can cause conflict between fishers and managers. The theoretical foundation for the conventional single species legislation is increasingly challenged and there is an urgent need to examine and evaluate the fishing and management patterns from an ecosystem perspective and revise the legislation where necessary. The fishing pressure on most of the small species is only a fraction of the pressure on large fish species, and therefore there is huge potential for increased production and more balanced exploitation if the overall fishing pressure was directed away from the large fish towards the small. In fact, this is what is already happening in many African fisheries, as evidenced by the huge increase in their catches, but it is taking place without comprehensive scientific evaluation of pressures, ecosystem effects or governance. Small fish are processed, sold and eaten whole. Most of the catch is simply sun-dried which is the most environmentally friendly and energy-efficient processing technology available, requiring limited investments to obtain potentially highquality products, although rainy seasons limit year-round preservation, and spoilage through overheating and rainfall remain serious issues. In addition, small whole fish are among the most vital suppliers of micronutrients, such as vitamins, iodine,

PUBLICATION RECORD

CITATION MAP

EXTRACTION MAP

CLAIMS

  • No claims are published for this paper.

CONCEPTS

  • No concepts are published for this paper.

REFERENCES

Showing 1-100 of 154 references · Page 1 of 2

12
Next

CITED BY

Showing 1-34 of 34 citing papers · Page 1 of 1