Volume 1 Pages 1 - 23 (May 1986)

Citation: Rowe-Rowe, D. (1986) African Otters - is their Existence Threatened?  IUCN Otter Spec. Group Bull. 1: 9 - 11

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African Otters - is their Existence Threatened?

David Rowe-Rowe

Natal Parks Board, Pietermaritzburg, South Africa

Three otter species occur in Sub-Saharan Africa. The Cape clawless otter Aonyx capensis inhabits rivers and lakes, and all streams in which there is sufficient water to support crabs, frogs, and catfish or mudfish, but is absent from the central rain forest area where the Congo clawless otter Aonyx congica is present. The spotted-necked otter Lutra maculicollis appears to be more dependent on permanent clear water than is A. capensis, and is the dominant otter in most of the large lakes as well as In some floodplain systems.

A. capensis has evolved primarily as a feeder on crabs, whereas L. maculicollis is better adapted for fish capture. Therefore, in countries which are poor in fish faunas the clawless otter is dominant and the spotted-necked otter is likely to be rare. On the other hand African floodplain rivers and most of the large lakes are particularly rich in fish, arid it is in such habitats that L. maculicollis is dominant. Very little is known about the biology of A. congica.

None of these three otters is listed in the IUCN Red Book, but this does not mean that we should complacently sit back. There are serious problems.

When threats to the continued existence of an animal are mentioned one tends to think immediately of the direct killing of the animals. In a recent survey on otter status and distribution done in 23 African countries there were no reports of large-scale killing of otters for the fur trade. In all of these countries some otters are killed for their skins, or because they are believed to be pests, or because they are regarded as competitors for fish. The survey revealed, however, that the greatest threats to otters emanate from increasing human populations and damage to the habitat.

Food production in Africa fell below population growth about 15 years ago, and the need to cope with the food demand has led to excessive rates of soil erosion following increased and often unsound agricultural practices, coupled with overgrazing by livestock. These practices are responsible for rapid soil loss, increased water turbidity, and silting, which results in greatly reduced numbers or the extermination of aquatic insects, crabs, frogs and fish. Otters which are at the end of the food chain are directly affected by the loss of these aquatic organisms.

In many areas water draining off fertilised lands can cause adverse chemical changes in streams, or could pollute them with pesticide residues, once again affecting aquatic life.

The increasing demand for agricultural land has led to many swampy areas being 'reclaimed' by draining them. This not only means the loss of an aquatic habitat, but it also affects streamflow or water quality below the area.

Associated also with increasing human populations is urban expansion which tends to produce local disturbances affecting the permeability of the soil and resulting in increased run-off. In addition, urbanisation generally leads to industrial expansion, resulting in pollution of waters downstream of the development.

But all is not lost. Otters receive total protection in six of the African countries surveyed, and in all but one country there are national parks and game or nature reserves in which otters are generally safe from disturbance. One must remember, though, that the laws protecting wildlife are only as good as the degree of enforcement, and that protection of the animal starts with conservation of the habitat.

Conservation problems in Africa are complex. The protection of wildlife by having laws and national parks is important, but more important is the simultaneous conservation of natural resources outside of national parks and nature reserves. To do this conservation authorities should start with the base of the biological pyramid and educate people in sound agricultural practices, soil conservation, water conservation, and wise use of the grasslands and forests.

Increase in human population is the greatest single threat to wildlife in Africa where the population growth rate is 3% per annum. The 1980 population of 450 million is expected to have almost doubled by the year 2000. If wildlife is to survive the human population growth must be contained - not an easy task in a continent where most of the people are uneducated. Average primary school attendance in African countries is 11% of the population, with only a further 1% attending secondary school. Furthermore, amongst the many rural people a man's status is usually still rated as being proportional to his number of wives, children and livestock.

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