Bio-survey of Plankton as indicators of water quality for recreational activities in Calabar River, Nigeria

With the increasing recognition of Calabar as a global tourist destination, the suitability of Calabar River for recreational activities by tourists was investigated. The aim was to use phytoplankton and zooplankton characteristics to assess the water quality of the Calabar River. Phytoplankton and zooplankton samples were collected from four stations along the river and carried in plastic containers at 4oC to the laboratory for taxonomic and diversity index analyses. Water samples were also collected from the sampling stations for physico-chemical analysis. In total, 331 phytoplankton individuals were identified from sixty-six species in sixty genera and six taxonomic groups. The most abundant taxon was Bacillariophyceae 212 (64.05%), followed by Cyanophyceae 42 (12.69%), Chlorophyceae 40 (12.08%); Dinophyceae 16 (4.83%); Chrysophyceae 12 (3.63%) and Xanthophyceae 9 (2.72%). Similarly, the diatoms were highest in species richness (54.55%) followed by Cyanophyceae (18.18%), Chlorophyceae (12.12%), Dinophyceae (6.06%), Chrysophyceae (4.55%), and Xanthophyceae (4.55%). Among the zooplankton, the Copepods were the most abundant (54.89%). Others were Protozoa (14.13%), Polychaeta larvae (7.07%), Cyclopoida (5.43%), Cladocera (5.43%), Arthropoda (4.89%), Ostracoda (3.26%), Rotifera (2.72%), Malacostraca (1.09%), and Foraminiferida (1.09%). The copepods were highest in species richness (13), representing 36.11% of the total. The other zooplankton taxonomic groups were Protozoa (16.67%), Cyclopoida (11.11%), Ostracoda (8.33%), Rotifera (8.33%), Cladocera (5.56%), Malacostraca (5.56%), Arthropoda (2.78%), Polychaeta larvae (2.78%), and Foraminiferida (2.78%). We did not observe any preponderance of harmful phytoplankton or zooplankton in the Calabar River during the study. The river showed no evidence of stress beyond her carrying capacity, and there was no evidence of any harmful environmental conditions that is detrimental to recreational activities in the Calabar River. We assess Calabar River as being biologically suitable for contact recreational activities, from the point of view of her plankton characteristics.