Zooplanktonic Community Assessment over Space and Time: A biomonitoring Tool in an Artificial Lake
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Date
2022
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Asian Journal of Research in Zoology
Abstract
Aims: The prime objective of this study is to determine the taxonomic composition of the
zooplankton fauna of Esa-Odo Reservoir in Osun State and determine the spatial (horizontal and
vertical) and seasonal variations in the composition, distribution abundance, and community
structure of the zooplankton community in the reservoir.
Study design: sampling stations were selected horizontally and vertically to cover the entire zones
of the reservoir. Planktonic samples were collected at two months intervals for two years.
Methodology: Samples were collected from the depth using an improvised Meyer’s water sampler.
Net and Total plankton were sampled by filtration and sedimentation methods. Planktonic samples
were preserved as 5% formalin and 1% Lugol’s solution. Measurement, enumeration, and scaled
pictures of the recorded zooplankton were taken using a photomicrograph. The taxonomic
composition of zooplankton biota was determined using identification keys. Data analysis was done
using PAST Statistical Package. ANOVA was used to determine the spatio-temporal variations.
Results: Fiftyty-three (53) pecies of total zooplankton recorded in this study belong to 4 groups:
Rotifera, Cladocera, Copepoda, and Insecta. Rotifera was the most represented group (61.21%).
Horizontally, 24 species with the highest mean abundance characterized the lacustrine; while 12
species and 10 species were unique to the transition and riverine zones, respectively. Vertically,
most species had their mean abundance decreased from the surface to the bottom of the reservoir.
Original Research ArticleOmoboye et al.; AJRIZ, 5(1): 31-47, 2022; Article no.AJRIZ.83773
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A total of nine (9), two (2) and one (1) species were peculiar to the surface, bottom and mid-depth,
respectively. Zooplankton organisms were most abundant during the dry season.
Conclusion: Esa-Odo Reservoir comprised highly diversified zooplankton fauna with great
potential to support rich aquatic community and fishery production. The reservoir can be classified
as fairly clean based on the abundance of the rotifer group. However, the lake should be subjected
to regular proper monitoring because of the presence of some pollution tolerant copepod species
identified among the zooplankton fauna.