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Research & Reviews : Journal of Ecology

Zooplankton Assemblages and Limnological Properties of the Choba Segment, Upper Reaches of New Calabar River, Port Harcourt, Nigeria

  1. Benjamin Bameyi Otene
  2. Nnadi P. C.
  3. Ikpinima O. G

Abstract

The zoological assemblage and the limnological characteristics of the Choba segment of the upper reaches of New Calabar river, Port Harcourt was studied between March and May, 2021. Three stations were sampled for water and zooplankton using a 45 m plankton net and plastic bottles, respectively, in accordance with the APHA's standard procedure. The results showed that a total of 696 zooplankton individuals consisting of 22 species from four taxonomic groups dominated by Copepoda and Rotifera were identified. The highest zooplankton abundance (296 Org/l) representing 45.88% was observed in Station 2 while the least value (184 Org/l) representing 8.91% was observed in Station 3. The observed dominant species were Euglipha verdata, Frontonia leucas (Protozoa), Bosmina lonirusteri (Cladocera), and Mesocyclops badonical (Copepoda). Simpson dominance index ranged between 0.943 (Station 1) and 0.947 (Station 2) while Shannon index ranged between 2.968 (Station 1) and 2.995 (Station 2). The mean values of some physicochemical variables studied were, pH (6.23±0.69), dissolved oxygen (DO) (5.60±0.11 mg/l), electrical conductivity (EC)(280.00±7.0 μs/cm), sulphate (SO4) (83.00±1.00 mg/l), and turbidity (4.91±0.43 cm) which were all within the permissible limits of the World Health Organization and did not differ spatially at P<0.05 except biochemical oxygen demand (BOD), EC and NO3. With the exception of NO3, SO4, and NO3, whose maximum levels were seen in Station 2, most variables recorded their highest values in March. The presence of some pollution indicator species and exceedance of permissible limits of the WHO by some limnological parameters showed that the river is stressed. Awareness campaign should therefore be frequently carried out to regulate the level of anthropogenic activities in the area.

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