Preliminary survey of harmful algal species in the Bonny Estuary, Niger delta, Nigeria

A preliminary survey of harmful algal species in the Bonny Estuary was conducted in the Dry Season (October to December) 2017, to enhance ecosystem-based management strategies for harmful algal blooms; through HAB detection. The experimental approach includes: the deployment of an ACRC GIS tool to select nine geo-reference stations; the collection of plankton samples with the plankton net to provide a qualitative account of harmful algae and a horiba water checker to investigate the physico-chemical characteristics of the Estuary. The result obtained, revealed some level of variability between the physico-chemical parameters and the stations. However, the values of the physicochemical parameters recorded ranged from 29.53 ºC to 32.30 ºC; 7.66 mg/l to 12.73mg/l; 6.66 to 7.23; 5.53ppm to 14.16ppm and 4.10ppt to 10.20ppt for water temperature, dissolved oxygen, pH, total dissolved solid and salinity respectively in the nine stations. The harmful algae recovered were a total of three classes, representing twelve genera and 12 species. Bacillariophyceae had the highest number of species (10) while Chlorophyceae and Cyanophyceae recorded the lowest number of species (1). This study therefore, provided evidence of the presence of harmful algae in the Bonny Estuary. However, the potential of these algae to cause harm either through the production of toxins or excessive accumulations of biomass is triggered by the type of strain, physico-chemical variables, and biogeography of the area. Thus, the need to plan adequate monitoring programs to develop early warning systems and models for short term forecast of Harmful Algal Blooms is highly recommended.