Benthic Macroinvertebrates as Ecological Indicators in Sampaloc Lake, San Pablo City

Abstract

The diversity of macrobenthic invertebrates is an effective biological indicator to assess the ecological status of the lake environment. In Sampaloc Lake, San Pablo City, Laguna, there is limited documentation of macrobenthic invertebrate diversity and ecological patterns. A total of 8 quadrats (1m x 1m) in four established sampling stations were used to obtain samples with an abundance of 690 organisms that were classified into nine taxa (S=9). Most of the macrobenthic invertebrates found in the study were from phylum Annelida (Naididae), phylum Arthropoda (Chironomidae), and phylum Mollusca. The most abundant taxon was Naididae which is an effective indicator of water quality since they are usually found on organically polluted waters. The overall status of macrobenthic fauna in Sampaloc Lake is very low, with a biotic index of H’=1.942, corresponding to a water quality classification of “Moderately polluted”. The pollution level was supported by the Family Biotic Index result of 6.74 with the verbal interpretation “poor water quality”. The biodiversity assessment of Sampaloc Lake indicates low species diversity, primarily due to high nutrient concentration or eutrophication brought by intensive aquaculture. Ammonia levels in Sampaloc Lake exceeded the recommended level and were found to be toxic on macrobenthic fauna affecting their reproductive capacity and species diversity. Reducing anthropogenic pressures and adopting a holistic lake management approach are crucial to avert future deterioration and biodiversity loss.