Effects of Hurricane Katrina on benthic macroinvertebrate communities along the northern Gulf of Mexico coast

The effects of Hurricane Katrina on benthic fauna and habitat quality in coastal waters of Louisiana, Mississippi, and Alabama, USA, were assessed in October, 2005, 2 months after the hurricane made landfall between New Orleans, LA and Biloxi, MS. Benthic macrofaunal samples, sediment chemical concentrations, and water quality measurements from 60 sites in Lake Pontchartrain and Mississippi Sound were compared with pre-hurricane conditions from 2000–2004. Post-hurricane benthic communities had significant reductions in numbers of taxa, H′ diversity, and abundance as well as shifts in composition and ranking of dominant taxa. These effects were not associated with changes in chemical contamination, organic enrichment of sediments, or hypoxia and were likely due to hurricane-related scouring and changes in salinity.     

Variability in the identification and enumeration of marine benthic invertebrate samples and its effect on benthic assessment measures

Studies designed to measure anthropogenic impacts on marine benthic communities depend on the ability of taxonomists to consistently discriminate, identify, and count benthic organisms. To quantify errors and discrepancies in identification and enumeration, 20 samples were completely reprocessed by another one of four participating laboratories. Errors were detected in 13.0% of the data records, affecting total abundance by 2.1%, numbers of taxa by 3.4%, and identification accuracy by 4.7%. Paired t-tests were used to test for differences in the Benthic Response Index (BRI), total abundance, numbers of taxa, and the Shannon-Wiener index between the original and the reanalysis data. Differences in the BRI were statistically insignificant. Although statistically significant differences were observed for numbers of taxa, total abundance, and the Shannon-Wiener index, the differences were small in comparison to the magnitude of differences typically observed between anthropogenically affected and reference sites.     

Characterization of Benthic Communities and Physical Habitat in the Stanislaus, Tuolumne, and Merced Rivers, California

The primary goal of this study was to characterize physical habitat and benthic communities (macroinvertebrates) in the Stanislaus, Tuolumne and Merced Rivers in California’s San Joaquin Valley in 2003. These rivers have been listed as impaired water bodies (303 (d) list) by the State of California due to the presence of organophosphate (OP) insecticides chlorpyrifos and diazinon, Group A pesticides (i.e., organochlorine pesticides), mercury, or unknown toxicity. Based on 10 instream and riparian physical habitat metrics, total physical habitat scores in the Stanislaus River ranged from 124 to 188 (maximum possible total score is 200). The highest total habitat score was reported at the upstream site. Tuolumne River physical habitat scores ranged from 86 to 167. Various Tuolumne River physical habitat metrics, including total habitat score, increased from downstream to upstream in this river. Merced River physical habitat scores ranged from 121 to 170 with a significant increase in various physical habitat metrics, including total habitat score, reported from downstream to upstream. Channel flow (an instream metric) and bank stability (a riparian metric) were the most important physical habitat metrics influencing the various benthic metrics for all three rivers. Abundance measures of benthic macroinvertebrates (5,100 to 5,400 individuals) were similar among the three rivers in the San Joaquin watershed. Benthic communities in all three rivers were generally dominated by: (1) Baetidae species (mayflies) which are a component of EPT taxa generally considered sensitive to environmental degradation; (2) Chironomidae (midges) which can be either tolerant or sensitive to environmental stressors depending on the species; (3) Ephemerellidae (mayflies) which are considered sensitive to pollution stress; and (4) Naididae (aquatic worms) which are generally considered tolerant to environmental stressors. The presence of 117 taxa in the Stanislaus River, 114 taxa in the Tuolumne River and 96 taxa in the Merced River implies that the benthic communities in these streams are fairly diverse but without a clear definition of benthic community expectations it is unknown if these water bodies are actually impaired.     

Empirical assessment of incorporating sediment quality triad data into a single index to distinguish dominant stressors between sites

Benthic infaunal community structure, sediment contamination, and sediment toxicity data (Sediment Quality Triad) were condensed into a single index based on the area of tri-axial plots, which were examined in relation to various habitat parameters. The purpose was to assess its utility for evaluating the relative impact of contaminants versus other stressors on benthic communities. The regression relationship between the areal index and the Effects Range?CMedian quotient (ERMq) was used to separate contaminant-impacted sites from sites impacted by hypoxia in Chesapeake Bay. Regression using the areal index and bottom oxygen confirm the utility of the approach. Data from Delaware, Galveston, and Biscayne Bays were also examined to determine if the approach may be effective in other estuaries.     

Relating Benthic Infaunal Community Structure to Environmental Variables in Estuaries using Nonmetric Multidimensional Scaling and Similarity Analysis

In 1994, 19 stations were sampled (2 replicates/station) with Young grabs in association with the EMAP-Estuaries Carolian Province Base Monitoring in Florida. A total of 295 unique benthic infauna taxa and 9647 individuals were identified and enumerated. Environmental data (bottom-water quality, sediment grain size, sediment metals, and organics) and benthic community data were analyzed using hierarchical agglomerative cluster analysis and ordination via nonmetric multidimensional scaling. Bray-Curtis similarities and Euclidean distance were used as the distance measures for biotic and abiotic data, respectively. Multivariate analyses were complemented by examining incremental contributions of benthic taxa to similarity values using a percentage similarity technique. A low-salinity site in a tributary to the St. Johns River had benthic communities uniquely different from those of moderate-to high-salinity sites. A diverse assemblage of polychaetes, gastropods, bivalves, amphipods, sipunculans, and phoronids was consistently associated with relatively unimpacted sites in the Indian River Lagoon. Infaunal community structure in the northern portion of the study area was influenced by the nearby Atlantic Ocean. Community shifts in association with latitudinal gradients and concentrations of sediment metals and organics were apparent. The nonparametric multivariate techniques used in this study were particularly effective at delineating and defining fine-scale community differences.     

城镇化对西苕溪大型底栖动物群落的影响

于2004—2010年5月对西苕溪流域20个参照点,5个中度干扰点以及2个重度干扰点的底栖动物进行了调查,共鉴定出74科190属226个种;受干扰后,底栖动物群落物种丰富度、EPT物种丰富度、Shannon-wiener多样性指数和B-IBI指数显著下降,BI指数显著升高。CCA分析结果表明,参照、中度和重点干扰样点的底栖动物群落差异明显。城镇化引起的溪流水温上升、营养盐升高、泥沙输入量增多和堤岸固化是导致溪流底栖动物群落退化的主要原因。     

Assessing the Effects of Non-Point Source Pollution on American Samoa’s Coral Reef Communities

Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels.     

Influence of anthropogenic transformations of river bed on plant and macrozoobenthos communities

This study describes the influence of urban area on plant communities and benthic invertebrates inhabiting the S?upia River (northern Poland). Ten plant communities and 37 macrozoobenthos taxa were determined during four seasonal samplings at 25 sampling sites (October 2005 and January, April, and August 2006). The obtained data set was statistically evaluated in order to reveal the influence of anthropogenic transformations on the investigated communities against the background of other abiotic factors. Multivariate regression tree (MRT) method was used for vegetation, while for benthic fauna, both MRT and artificial neural network (ANN) methods were applied. The following explanatory variables were used: season, water temperature, and salinity; location of a sampling site; degree of human impact on the riverbed; microhabitat; and substrate type. MRT analyses showed significant differences in plant community structure depending on the location of a sampling site, indicating the influence of anthropogenic pressure, while macrozoobenthos composition differed significantly only between seasons. The overall ANN model proved the importance of type and location of a sampling site for the approximation of benthic fauna density. Additionally, influence of the explanatory variables on the consecutive macrozoobenthos taxa was analyzed on the basis of separate ANN.     

Littoral diatoms as indicators of recent water and sediment contamination by metals in lakes

We studied the response of benthic diatoms to recent metal contamination in littoral cores collected at 25 sites in 11 lakes situated at different distances from a smelter in the Rouyn-Noranda mining region (Quebec). Diatom response was described in terms of density, diversity, and taxonomic composition of the entire assemblages and as abundance of individual indicator taxa. Metal concentrations were measured in sediment and in the overlying water (as total dissolved and as free-ions). Sediment metal contamination was significantly higher in lakes located <10 km from the smelters than in lakes farther away. Such difference was not significant when metal concentrations in the overlying water were considered. Metal contamination did not affect diatom density, which indeed was highest in the most contaminated lake. Diversity (either measured as number of taxa or as Shannon and evenness indices) was instead significantly higher in lakes close to the smelter than elsewhere. Redundancy analysis indicated that diatom composition changed along a gradient in alkalinity (CO?) and one in sediment metal contamination (Cd, Hg, Cu). We identified three diatom taxa (Fragilaria construens var. venter, F. construens var. pumila, and Brachysira vitrea) that increased in relative and absolute abundance with metal contamination. Benthic diatom responses at the community (density, diversity, assemblage composition) and population levels (abundance of selected benthic taxa) were stronger to the sediment metal contamination than to the contamination of overlying water. Comparisons with available literature indicated that, for monitoring recent sediment contamination, diatoms in littoral sediments are preferable to invertebrates that mostly respond to overlying water. Diatoms in littoral cores are therefore unique as tools for monitoring recent contamination of lake sediments.     

A survey of benthic invertebrates in the Suwannee River,Florida

Benthic invertebrate communities were surveyed in a 233 km reach of the middle and lower Suwannee River in Northwestern Florida in the winter 1987 and early summer 1988 to determine their abundance and distribution as potential foods of the Gulf sturgeon, Acipenser oxyrhynchus desotoi, and to determine the effects of possible natural and human-induced disturbances to the communities. In substrates of the tidal oligohaline to mesohaline lower reach of the East Pass site I (km 2) and site II West Pass (km 5) near the Gulf of Mexico, densities of tube dwelling and free swimming amphipods, polychaetes, oligochaetes, and dipterans in the PONAR grabs were moderate (100–999 {iex} individuals/m²) to abundant (1000–9999 {iex} individuals m^–2). Also, at sites I and II, low (10–99 {iex} individuals m^–2) to moderate densities of dipteran Chironomidae and olive nerite snail were collected in hardboard multiplate artificial substrate samplers. Diversities of benthic invertebrates in both grabs and hardboard multiplates were relatively low. Baetid mayflies were moderately abundant in the dip net samples. Upriver from sites I and II, the transition of an oligohaline tolerant benthic community to a freshwater one was abrupt due to strong freshwater flow. At sites III (km 48) and IV (km 89), benthic invertebrate populations were low to moderate in hardboard multiplate and dip net samples. In the middle reach (km 101 to km 233), aquatic insects were predominant and included; chironomids, mayflies, and beetles, and also, freshwater gammarid amphipods, gastropods, and the Asian clam. In winter, the bottom substrates at sites VII (km 153) and VIII (km 205) contained diverse and dense populations of Chironomidae (5932 m^–2), the greatest density for a major taxonomic group recorded in this survey. Crayfish were collected in low densities only in artificial substrate samplers from sites IV to IX. Leeches were widespread in the study area. Empirical Biotic Index values that reflect impacts of organic wastes on benthic invertebrate communities were within a narrow range, 3.16 to 6.38, and indicated slightly enriched to enriched water. Of the total 186 benthic invertebrate taxa, 82% had quality values 0 to 5 that indicate overall clean water conditions. The predominant benthic invertebrates in the Suwannee River were detritivorous and the communities reflected oligotrophic to mesotrophic waters.     

An approach for identifying the causes of benthic degradation in Chesapeake Bay

We developed an index to differentiate between low dissolved oxygen effects and sediment contamination effects for sites classified as degraded by the Chesapeake Bay Benthic Index of Biotic Integrity (B-IBI), using discriminant analysis. We tested 126 metrics for differences between sites with low dissolved oxygen and sites with contaminated sediments. A total of 16 benthic community metrics met the variable selection criteria and were used to develop a discriminant function that classified degraded sites into one of two stress groups. The resulting discriminant function correctly classified 77% of the low dissolved oxygen sites and 80% of the contaminated sites in the validation data.     

Trace Element Contamination in Benthic Macroinvertebrates from a Small Stream Near a Uranium Mill Tailings Site

Direct measurement of the accumulation of non-radioactive traceelements in aquatic biota near uranium mining or processing sites has been relatively rare, with greater focus on the radiological activity in the adjacent soils and groundwater. To evaluate the potential ecological concern associated with trace elements at a former uranium mill site in southeasternUtah, benthic macroinvertebrates were collected and analyzed for 17 trace elements from multiple locations within a small on-site stream, Montezuma Creek, and a nearby reference stream. Key questions of this study relate to the spatial and temporalextent of contamination in aquatic biota, the potential ecological risks associated with that contamination, and the usefulness of benthic macroinvertebrates as a monitoring tool at this site. Composite samples of similar macroinvertebrate taxa and functional feeding groups were collected from each site over atwo year period that was representative of normal and dry-yearconditions. In both years, mean concentrations of arsenic,molybdenum, selenium, and vanadium were significantly higher (afactor of 2–4 times; P < 0.05) in macroinvertebrates collectedfrom one or both of the two Montezuma Creek sites immediatelydownstream of the mill tailing site in comparison toconcentrations from reference locations. Mean uraniumconcentrations in invertebrates immediately downstream of themill site were more than 10 times higher than at reference sites.The site-to-site pattern of contamination in Montezuma Creekinvertebrates was similar in 1995 and 1996, with mill-relatedtrace elements showing a downstream decreasing trend. However,nine of seventeen contaminant concentrations were higher in thesecond year of the study, possibly due to a higher influx of deepgroundwater during the drier second year of the study. Apreliminary assessment of ecological risks, based on the benthicmacroinvertebrate bioaccumulation data, suggests that aquatic andterrestrial population risks are low. Benthic macroinvertebratesappeared to be sensitive integrators of trace element inputs tothe aquatic environment from a former uranium mill tailing site,and provided useful spatial and temporal patterns ofcontamination not easily obtained using conventional surfacewater or groundwater measures.     

Maximum ecological potential of tropical reservoirs and benthic invertebrate communities

The Reference Condition Approach (RCA) is now widely adopted as a basis for the evaluation of the ecological quality of water bodies. In accordance with the RCA, the integrity of communities found in a given location should be analyzed according to their deviation from the communities that would be expected in the absence of anthropogenic disturbances. The RCA was used here with the aim of defining the Maximum Ecological Potential (MEP) of tropical reservoirs located in the hydrographical basin of the Paraopeba River in the state of Minas Gerais, Brazil. Among the reservoirs, Serra Azul is used as a water supply and is located in a core area of environmental protection where tourism is not allowed and the native vegetation is conserved. The benthic macroinvertebrate communities at 90 sites located in three reservoirs were analyzed and sampled every 3 months over 2 years. The temporal patterns of the communities in the three reservoirs were analyzed (2nd-STAGE MDS and ANOSIM) and were not significantly related to seasonal fluctuations in temperature and precipitation. Twenty-eight sites belonging to the Serra Azul reservoir were selected to define the MEP of these reservoirs because these sites had the lowest human disturbance levels. The macroinvertebrate taxa present in the selected MEP sites are similar to those of natural lakes and different from the communities of disturbed sites. The biological classification of these sites revealed two groups with distinct macroinvertebrate communities. This distinction was related to climatic variables, bottom substrate type, the presence of gravel/boulders, coarse sand, silt, clay or muck, depth, and the shoreline substrate zone. These two subsets of biological communities and respective environmental conditions can serve as a basis for the future implementation of ecological quality monitoring programs for tropical reservoirs in the study area. This approach can also, however, be implemented in other geographic areas with artificial or heavily modified water bodies.     

中国北方河流底栖动物群落季节性演替对水生态环境质量评价的影响

大型底栖动物是评价水生态质量最常用的生物类群,鉴于水生昆虫的生活史特点,在一年当中群落结构会发生季节性变化,如何利用底栖动物数据准确评价水生态质量状况,反映客观实际,值得探讨。将黑龙江省2012—2015年水生生物试点监测47个采样点的108组底栖动物数据进行比较,对群落结构的相似性、物种的更替率和BMWP指数评价结果进行分析,探讨群落的演替及BMWP指数的变化规律。结果表明不同时间采集的样品底栖动物群落之间存在较大差异,评价的结果也存在差异,越是水环境质量好的区域,这种差异越明显。利用底栖动物评价水生态状况,宜选择长时间段的多个采集数据,经统计整理后,利用复合样方(年均值)的特征,评价一段时间内(如以年为单位)的水生态质量状况,使评价结果更具准确性。     

A Regional Survey of the Microbiological Water Quality along the Shoreline of the Southern California Bight

A regional survey of the microbiological water quality along the shoreline of the Southern California Bight (SCB), from Point Conception south to Ensenada, Mexico, was conducted during August, 1998, by 36 agencies under the coordination of the Southern California Coastal Water Research Project (SCCWRP). Microbiological water quality was assessed by calculating the percentage of shoreline-mile-days that exceeded bacterial indicator thresholds for total and fecal coliforms, total/fecal ratios, and enterococci. Sample sites were selected using a stratified random sampling approach, with the SCB recreational shoreline divided into six strata: high- and low-use sandy beaches, high- and low-use rocky shoreline, and perennial and ephemeral freshwater outlets. Samples were collected on a weekly basis at a total of 253 sites, beginning on August 2^nd, 1998 and continuing for five weeks. Samples were analyzed by 22 participating labs using their normal methods (multiple tube fermentation, membrane filtration, Colilert® and/or Enterolert®). All labs met testing criteria established through intercalibration exercises and quality control check samples distributed during the sampling period. Nearly 95% of the shoreline-mile days did not exceed daily and monthly bacterial indicator thresholds, demonstrating good bacteriological water quality along the SCB shoreline. Freshwater outlets, comprised mainly of storm drains, had the poorest water quality with 60% and 40% of the shoreline-miles exceeding monthly and daily thresholds, respectively. Freshwater outlets were also more likely to demonstrate exceedances by multiple indicators at a single site, and repeat exceedances at sites over the five-week period. Compared with the southern California beaches, Mexican beaches had nearly 5 times the number of exceedances for total and fecal coliforms, and nearly 8 times the number of exceedances for total/fecal ratios.     

Relations of Habitat-Specific Algal Assemblages to Land Use and Water Chemistry in the Willamette Basin, Oregon

Benthic algal assemblages, water chemistry, and habitat were characterized at 25 stream sites in the Willamette Basin, Oregon, during low flow in 1994. Seventy-three algal samples yielded 420 taxa — mostly diatoms, blue-green algae, and green algae. Algal assemblages from depositional samples were strongly dominated by diatoms (76% mean relative abundance), whereas erosional samples were dominated by blue-green algae (68% mean relative abundance).Canonical correspondence analysis (CCA) of semiquantitative and qualitative (presence/absence) data sets identified four environmental variables (maximum specific conductance, % open canopy, pH, and drainage area) that were significant in describing patterns of algal taxa among sites. Based on CCA, four groups of sites were identified: streams in forested basins that supported oligotrophic taxa, such as Diatoma mesodon;small streams in agricultural and urban basins that contained a variety of eutrophic and nitrogen-heterotrophic algal taxa; larger rivers draining areas of mixed land use that supported planktonic, eutrophic, and nitrogen-heterotrophic algal taxa; and streams with severely degraded or absent riparian vegetation (> 75% open canopy) that were dominated by other planktonic, eutrophic, and nitrogen-heterotrophic algal taxa. Patterns in water chemistry were consistent with the algal autecological interpretations and clearly demonstrated relationships between land use, water quality, and algal distribution patterns.     

Derivation of no-effect and reference-level sediment quality values for application at Saskatchewan uranium operations

To date, the majority of empirical approaches used to derive sediment quality values (SQVs) have focused on metal concentrations in sediment associated with adverse effects on benthic invertebrate communities. Here, we propose the no-effect (NE) approach. This SQV derivation methodology uses metal concentrations in sediment associated with unaffected benthic communities (i.e., from reference sites and lightly contaminated no-effect sites) and accounts for local benthic invertebrate tolerance and potential chemical interactions at no-effect exposure sites. This NE approach was used to propose alternative regional SQVs for uranium operations in northern Saskatchewan. Three different sets of NE values were derived using different combinations of benthic invertebrate community effects criteria (abundance, richness, evenness, Bray–Curtis index). Additionally, reference values were derived based solely on sediment metal concentrations from reference sites. In general, NE values derived using abundance, richness, and evenness (NE1 and NE2 values) were found to be higher than the NE values derived using all four metrics (NE3 values). Derived NE values for Cr, Cu, Pb, and V did not change with the incorporation of additional effects criteria due to a lack of influence from the uranium operations on the concentrations of these metals in sediment. However, a gradient of exposure concentrations was apparent for As, Mo, Ni, Se, and U in sediment which allowed for tolerable exposure levels of these metals in sediment to be defined. The findings from this assessment have suggested a range of new, alternate metal SQVs for use at uranium operations in northern Saskatchewan.     

Spatial scales and probability based sampling in determining levels of benthic community degradation in the Chesapeake Bay

The extent of degradation of benthic communities of the Chesapeake Bay was determined by applying a previously developed benthic index of biotic integrity at three spatial scales. Allocation of sampling was probability-based allowing areal estimates of degradation with known confidence intervals. The three spatial scales were: (1) the tidal Chesapeake Bay; (2) the Elizabeth River watershed; and (3) two small tidal creeks within the Southern Branch of the Elizabeth River that are part of a sediment contaminant remediation effort. The areas covered varied from 10^–1 to 10⁴ km² and all were sampled in 1999. The Chesapeake Bay was divided into ten strata, the Elizabeth River into five strata and each of the two tidal creeks was a single stratum. The determination of the number and size of strata was based upon consideration of both managerially useful units for restoration and limitations of funding. Within each stratum 25 random locations were sampled for benthic community condition. In 1999 the percent of the benthos with poor benthic community condition for the entire Chesapeake Bay was 47% and varied from 20% at the mouth of the Bay to 72% in the Potomac River. The estimated area of benthos with poor benthic community condition for the Elizabeth River was 64% and varied from 52–92%. Both small tidal creeks had estimates of 76% of poor benthic community condition. These kinds of estimates allow environmental managers to better direct restoration efforts and evaluate progress towards restoration. Patterns of benthic community condition at smaller spatial scales may not be correctly inferred from larger spatial scales. Comparisons of patterns in benthic community condition across spatial scales, and between combinations of strata, must be cautiously interpreted.     

Use of macroinvertebrate assemblages for assessing performance of stabilization ponds treating effluents from sugarcane and molasses processing

Wastewater discharge from sugarcane processing is a significant pollutant of tropical aquatic ecosystems. For most developing countries, monitoring of the level of pollutants is done mostly through chemical analysis, but this does not reflect potential impacts on aquatic assemblages. In addition, laboratory facilities for accurate concentration measurements are often not available for regular monitoring programs. In this study, we investigated the use of benthic macroinvertebrates for biological monitoring in western Kenya. Benthic macroinvertebrates were sampled in stabilization ponds treating wastewater from sugarcane- and molasses-based processing plants to assess their composition and abundance in relation to different concentrations of chemical variables. Optimum concentrations and tolerance values were identified for various taxa, and a biotic index was developed that combined tolerance values (ranked between 0 and 10) for the various macroinvertebrate taxa. A succession in composition and distribution of macroinvertebrate taxa was observed from the inlet to the outlet of the pond systems. Diptera dominated in the first ponds that had high concentrations of chemical oxygen demand (COD), biological oxygen demand (BOD₅), and nutrients, while intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) appeared as the concentrations dropped in subsequent ponds. The effluent quality was classified as “good,” “fair,” and “poor,” corresponding with biotic index value ranges 0–3.50, 3.51–6.50, and 6.51–10, respectively. During validation, the index grouped sites with respect to levels of measured environmental variables. The study revealed that the developed biotic index would help in monitoring the quality of sugarcane processing and molasses effluents before release into recipient aquatic ecosystems, replacing the need for costly chemical analyses.