Assessing the Water Quality of Creek Systems at Caraga State University-Main Campus, Philippines, using Macroinvertebrate-based Biotic Indices

Macroinvertebrates are widely utilized for monitoring water bodies and assessing water quality. In this study, macroinvertebrates were sampled from different gradients (upstream, midstream, and downstream) of four creeks within the main campus of Caraga State University. The study utilized a modified kick-net method to evaluate their species diversity, composition, and richness. A total of 20 taxa of macroinvertebrates from seven orders and 16 families were collected and identified across the subsampling stations. Gastropoda was the most abundant order, making up 65.51% of the total, with representatives from five families. Despite this abundance, the Shannon Diversity Index indicated very low diversity across all creek systems. However, the Pollution Tolerance Index (PTI) and the Biological Monitoring Working Party (BMWP) scores consistently showed good water quality across all subsampling stations. These results align with the Family Biotic Index (FBI) score, which suggests excellent water quality with no apparent organic pollution throughout the creeks. This study highlights the value of family-level identification in biomonitoring programs at CSU and similar environments. This method is cost-effective and practical, particularly in contexts with limited systematic knowledge of macroinvertebrates.