Microcystin concentrations in Nile tilapia (Oreochromis niloticus) caught from Murchison Bay, Lake Victoria and Lake Mburo: Uganda
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Date
2010
Journal Title
Journal ISSN
Volume Title
Publisher
Hydrobiologia
Abstract
Catches of the economically important
Nile tilapia (Oreochromis niloticus L.) from two
eutrophic tropical lakes in Uganda, Lake Mburo and
Murchison Bay, Lake Victoria, were examined to
determine the presence of microcystins (MCs) in gut,
liver and muscle of the fish. Analysis for MCs (RR,
LR and YR) in both fish and water samples was by
liquid chromatography coupled with mass spectroscopy
(LC-MS) method. Physico-chemical parameters
were also measured to establish the status of both
lakes. MC-RR was the most prominent MC detected
in Lake Mburo and Murchison Bay samples, there
was no evidence of significant seasonal variation in
the concentration of MCs in fish tissue. MCs were
detected in all water samples from both study lakes.
The mean concentration of MCs in water was found
higher in dry times for Lake Mburo (P\0.05) and
higher in wet times for Murchison Bay (P\0.05).
MC concentrations in the fish guts were positively
related with MC concentrations in water samples
from Murchison bay (P\0.05), no such correlation
was found in Lake Mburo. In eutrophic tropical lakes,
fish seem to have a high tolerance to the toxicity of
cyanotoxins including MCs. However, there is a
possibility of accumulating these toxins in their tissue
with the threat of transferring them higher up in the
food chain. Due to a low sample size and short
sampling period, the results can only serve to
highlight the potential risk of MC accumulation in
Nile tilapia in these lakes. Further studies are needed
for the purpose of risk assessment.
Description
Keywords
Microcystins, Lake Victoria, Lake Mburo, Nile tilapia
Citation
Semyalo, R., Rohrlack, T., Naggawa, C., & Nyakairu, G. W. (2010). Microcystin concentrations in Nile tilapia (Oreochromis niloticus) caught from Murchison Bay, Lake Victoria and Lake Mburo: Uganda. Hydrobiologia, 638(1), 235-244. DOI 10.1007/s10750-009-0047-8