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The literature on reliable indices, suitable bio-indicators, taxonomic level, frequency of measurements, and replications on benthic macroinvertebrates remains scarce in Malaysia. In addition, no review study was conducted using bibliometric analysis related to this discipline. Thus, this review aimed at gap and bibliometric analysis of publications on benthic macroinvertebrates as potential biological indicators. Sixty-six relevant scientific research papers from 2011 to 2022 were selected from the different databases. Then, descriptive and inferential statistical analyses were performed to assess the most reliable potential bio-indicators for river assessment and monitoring. Visualized statistics regarding bibliographic coupling analysis of authors, journal proceedings, and organizations were analyzed. The findings revealed that publications on invertebrates had no significant relationship in the last ten years (r = 0.241; p > 0.05). Most publications on macroinvertebrates in Malaysian rivers were found in the Scopus database (53.57%). Therefore, research articles must be published in journals included in the Journal Citation Report (JCR) to improve their quality further. Besides, benthic macroinvertebrates are commonly identified only up to the family level (47%) due to incomplete tropical benthic macroinvertebrates identification keys. As such, using environmental DNA methods with the power of next-generation sequencing has come in handy in bioindicator species identification. Among the potential bio-indicators found in Malaysian rivers are Chironomidae (9.11%), Baetidae (8.87%), and Hydropsychidae (8.62%). Based on the approaches utilized in analyzing benthic macroinvertebrates as bio-indicators, in-depth research such as bioassay and toxicology tests are necessary to realize the potential bio-indicators fully. Many studies focused on recreational rivers in Peninsular Malaysia. Therefore, research studies will be expanded to include urban rivers and rivers in S

Fish farming activities are essential to the economy of many countries. However, the discharge of fish farm effluents into nearby rivers can negatively impact benthic macroinvertebrates and water quality. In Malaysia, the correlation between water quality and benthic macroinvertebrates in areas impacted by fish farming has not been discussed comprehensively. Hence, this research investigated the connection between benthic communities and water quality in the Rawang sub-basin of the Selangor River using several statistical methods. Based on ease of accessibility and proximity to freshwater fish farms, and by using a random sampling method, seven sampling sites in six rivers were chosen including one reference site. Sampling of benthic macroinvertebrates and river water was carried out between April 2019 and March 2020. Principal Component Analysis (PCA) revealed that fish farming operations influence various water quality parameters such as dissolved oxygen (DO), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), pH, and ammonia-nitrogen. Canonical Correspondence Analysis (CCA) revealed that families Aeolosomatidae, Chironomidae, Lumbriculidae, Naididae, Planorbidae, and Tubificidae are tolerant to organic pollution. Their abundance was correlated with high BOD5, COD, turbidity, TSS, and ammonia-nitrogen. On the other hand, the families Caenidae, Gomphidae, Aytidae, Leptophlebiidae, Thiaridae, and Viviparidae are sensitive to organic pollution and were correlated with DO concentration. This research revealed that the correlation between benthic macroinvertebrate communities and water quality in the area is affected explicitly by fish farms.

This study aimed to evaluate benthic macroinvertebrates assemblages using the application of ecological indices in the Rawang sub-basin of the Selangor River with reference to determining the impacts of aquaculture practices on benthic macroinvertebrates. In total, seven sampling sites were selected, namely Guntong (SR1), Guntong’s tributaries (SR2, control site), Kuang (SR3 and SR7), Gong (SR4), Buaya (SR5) and Serendah (SR6) Rivers. Sites were selected using a random sampling technique and the accessibility and proximity to aquaculture farms. Macroinvertebrates were sampled from April 2019 to March 2020 using an aquatic kick net, a hand spade, and a D-frame dip net. Water samples were also taken. Twenty-seven families belonging to the Annelida, Mollusca and Athropoda phyla were identified using taxonomic keys. Tubificidae was found to be the most dominant family (36.79%) followed by Chironomidae (28.84%). The highest number of individuals from family Tubificidae was recorded in Gong River, where effluent was discharged from an aquaculture farm. The total abundance of benthic macroinvertebrates increased with increased proximity to the aquaculture farm. Based on Biological Monitoring Working Party score value, the water quality of sampling sites in close proximity to the aquaculture farm was polluted as compared to the control location. Family Biotic Index score showed that all sites were substantially polluted with organic pollution, with the control site being much less polluted. In conclusion, benthic macroinvertebrates assemblage was affected by effluent originating from aquaculture farm outlets. It is therefore necessary to conduct aquaculture farming using methods that are deemed to be environmentally friendly.