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Towards aquatic assessment of Lake Tumba, DR Congo

Zanga, Norbert (2013). Towards aquatic assessment of Lake Tumba, DR Congo. Uppsala : Sveriges lantbruksuniv.
ISBN 978-91-576-9133-0
eISBN 978-91-576-9134-7
[Licentiate thesis]

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The livelihoods of most communities around the 765 km2 Lake Tumba are dependent
on fish from the lake. Artisanal fishing and other pressures on the aquatic ecosystem
are likely to have increased over the last half century. However, few monitoring
programs follow these pressures and their influence on the aquatic ecosystem. The
main objective of this thesis was to contribute to an improved understanding of the fish
population in Lake Tumba to support the development of strategies for improving the
fishery as well as assessing changes in the fish population over time.

The fish population was characterized through regular monitoring from 2005 to
2010, with an emphasis on the methodology. This monitoring was complemented by a
survey of breeding sites for Tilapia congica within Lake Tumba, and an investigation
of the relationship between land use and fish catch around islands in the Congo River.

The Catch Per Unit Effort (CPUE) and Number Per Unit Effort (NPUE) differed
between sites and seasons, and with water depth and distance from shore. The greatest
fish weight was caught between 3.0 and 4.5 m depth, which might explain the larger
CPUE during the rainy season, as the water was deeper at the fixed fishing sites. The
local population has larger catches during the dry season.

Fewer species (n=42) were found in this study than in the 1959 survey (n=65
species). However, due to the difference in fishing methods, location and effort, it was
difficult to draw strong conclusions about how much the fish population had actually

The study of T. congica identified four major breeding sites, one of which was about
10 km long, and most nests were found in conjunction with Hippo grass (Vossia
cuspidata) and Water lily (Nymphaea stellata).
The study of fish near the Congo Islands caught 29 fish species. Cultivation area was
related to erosion and the number of species nested offshore from each island.

Due to the growing demand for fish, and the likelihood of
more dramatic
environmental change in the future, there is a need for developing management and
governance strategies, as well as for scientific monitoring of the ecosystem on which to
base management. The methodological aspects of this study and the actual findings
about current fish status can be of value in this development.

Authors/Creators:Zanga, Norbert
Title:Towards aquatic assessment of Lake Tumba, DR Congo
Year of publishing :2013
Number of Pages:46
I.Zanga, L. N., Inogwabini, B.I., Wilander, A., Willén, E. and Bishop, K. (2013). The Fish of Lake Tumba: Towards documentation of a resource for livelihoods and biodiversity (manuscript).
II.Inogwabini, B.I., Mputu, D.A. and Zanga, L. (2009). The use of breeding sites of Tilapia congica (Yhys & van Audenaerde 1960) to delineate conservation sites in the Lake Tumba, Democratic Republic of Congo: toward the conservation of the lake ecosystem. African Journal of Ecology 48(3), 800-806, doi: 10.1111/j.1365-2028.2009.01180.x.
III.Inogwabini, B.I. and Zanga, L. (2013). Fish species occurrence, estimates and human activities on the islands of the Congo River, Central Africa. Environmental Biology of Fishes, doi: 10.1007/s10641-013-0136-4
Place of Publication:Uppsala
Publisher:Dept. of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-9133-0
ISBN for electronic version:978-91-576-9134-7
Publication Type:Licentiate thesis
Full Text Status:Public
Agris subject categories.:M Aquatic sciences and fisheries > M01 Fisheries and aquaculture - General aspects
M Aquatic sciences and fisheries > M40 Aquatic ecology
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Fish and Aquacultural Science
Agrovoc terms:lakes, rivers, aquatic communities, tilapia congica, animal population, population structure, freshwater ecology, biodiversity, democratic republic of the congo
Keywords:Livelihoods, fish community, breeding sites, wet season, CPUE, NPUE, management, artisanal fishing, zoning process, T. congica
Permanent URL:
ID Code:10472
Department:(NL, NJ) > Dept. of Aquatic Sciences and Assessment
Deposited By: Staff Epsilon
Deposited On:24 May 2013 06:55
Metadata Last Modified:20 Feb 2015 11:31

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