Influence of Physico-chemical Variables on Fish Abundance in Ibikpe Creek, Niger Delta, Nigeria

Abstract

The relationship between physico-chemical parameters and fish abundance in Ibikpe Creek, Niger Delta, Nigeria, was investigated using monthly data collected from June to December 2025. Pearson correlation analysis, canonical correspondence analysis (CCA), and hierarchical cluster analysis (HCA) were applied to evaluate the associations between twelve physico-chemical variables and the abundance of 16 fish species. Brycinus nurse showed the strongest species–environment correlation, with nitrate (r = 0.880, P < 0.01), while Coptodon mariae showed a strong positive association with phosphate (r = 0.799, P < 0.01) and negative associations with water temperature and pH. Hemichromis fasciatus exhibited the highest number of significant correlations among the investigated species. The first three CCA axes explained 53.58% of the variation in the species–environment relationship, with Axis 1 accounting for 22.19% and showing the strongest association with nitrate (0.90). HCA grouped fish species into three clusters according to their shared associations with environmental variables. The findings indicate that nitrate and phosphate were among the strongest measured environmental correlates of fish abundance patterns in Ibikpe Creek. However, because nutrient sources were not directly measured, these relationships should be interpreted as observational associations rather than evidence of direct causation. The study provides baseline information for continued water-quality monitoring and future ecological investigations.