The farming of common carp in Africa

1. •Demand for fish in Africa outstrips
supply.
•Aquaculture can increase fish
availability (WorldFish Center, 2009), but
not until it uses better fish breeds and
species, as the case in crops and livestock
(Gupta et al., 2004).
•Common carp (exotic to Africa) is the
world’s most introduced fish species,
favoured for its fast growth rate and ease
of reproduction in ponds.
•Some African countries farm common
carp, but some fear the fish could disturb
their inland water quality, hence ban the
fish.
•Clarias gariepinus, a catfish native to
Africa, is also reported to disturb water
quality, hence banned in some countries
outside Africa.
•Both fishes feed on the bottom, but carp
changes its feeding niche in presence of a
stronger benthic fish (Rahman, 2015).
• Study done May to Aug 2018 at NAC,
Zomba, Malawi ; 4 treatments:
• Data collected monthly on turbidity,
secchi disk depth, total dissolved solids,
total suspended solids , and
other physicochemical
parameters using standard
methods on-site and/or
in the lab.
•
We thank the Regional Universities Forum for Capacity Building in Agriculture
(RUFORUM) for financial support.
1. Presence of carp and catfish in ponds brought changes in water quality, e.g. increased
turbidity, reduced secchi disk depth, etc
2.There was higher turbidity and greater changes in ponds with carp and catfish (T1, T2,
T3) than in control ponds (T4).
3.There was higher turbidity and greater changes in ponds with carp (T1) than in ponds
with catfish (T2) and in ponds with both carp & catfish (T3).
4.There was no significant difference in turbidity and other parameters between ponds
with catfish (T2) and ponds with both carp & catfish (T3).
Chirwa, E.R.*
, Kassam, D., Mtethiwa, A. & Jere, W.L.
Department of Aquaculture & Fisheries Science, Lilongwe University of Agriculture & Natural Resources (LUANAR), P.O.
Box 219, Lilongwe, Malawi
Effects of common carp (Cyprinus carpio) and the African catfish
(Clarias gariepinus) on water quality in ponds: relevance to
aquaculture enhancement in Africa
Compare the effects on water quality
caused by common carp and catfish C.
gariepinus in fish ponds.
*Corresponding author: erchirwa@gmail.com
Introduction
Objective
Materials & methods
1. Both common carp and the African catfish affect water quality in ponds
2. Common carp affects water quality more than the African catfish when the two
fishes occur in separate ponds.
3. The effects of common carp on water quality are reduced when it is cultured together
with the African catfish (polyculture).
4. Carp escapement from aquaculture into natural waters containing African catfish will
not alter water quality beyond what the catfish already does in those waters.
Conclusions
1. We suggest that in ecosystems where the African catfish naturally occurs (like in
much of Africa) common carp can be farmed to enhance aquaculture production
without compromising the water quality of the natural waters.
2. We recommend polyculture of carp and the African catfish not only to enhance
aquaculture production but also to mitigate against the possible effects of carp on
water quality.
Recommendations
1. Gupta, et al.,(eds.) 2004. Use of Genetically Improved and Alien Species for
Aquacult. & Conserv. Aquat. Biodiv. Africa. WorldFish Center Conf. Proc. 68, 113p.
2. Rahman, M.M. 2015. Role of common carp (Cyprinus carpio) in aquaculture
production systems, Front Life Sci., 8:4, 399-410.
3. World Fish Centre. 2009. Fish Supply and Food Security for Africa, World Fish
Centre: Penang, Malaysia.
Literature cited
Acknowledgements
Results