Asian Journal of Environment & Ecology

Delineating Ecologically Important Fish Habitats Using Ichthyoplankton Assemblages in the Coastal Waters of Tam Hai, Central Vietnam

Tran Cong Thinh — 2026-08-28

Fish eggs and larvae provide biological information for identifying areas associated with spawning and early development, yet ichthyoplankton remains poorly documented in tropical estuarine–coastal systems. This study examined ichthyoplankton at 16 stations in the coastal waters of Tam Hai, central Vietnam, during the dry season (April 2022) and rainy season (December 2022) to assess taxonomic composition, abundance, spatial organisation, seasonal variation, and associations with surface salinity. A total of 20,888 fish eggs and 1,812 fish larvae were collected, with 24 larval families identified. Mean fish egg density was substantially higher in the dry season than in the rainy season (634.30 ± 157.10 versus 60.18 ± 25.23 eggs/100 m³), while mean larval density was 50.28 ± 15.03 and 20.20 ± 5.71 ind./100 m³, respectively. Larval assemblage composition showed marked seasonal turnover and spatial differentiation across mangrove, transitional, and coral reef-associated habitats. Salinity was significantly associated with the abundance of four larval families: Gobiidae showed a negative association, whereas Nemipteridae, Dorosomatidae, and Terapontidae showed positive associations. The spatial separation between egg-rich and larva-rich stations indicates that early-life-stage distributions may reflect processes operating after spawning as well as habitat conditions. These findings provide baseline information for identifying areas associated with fish spawning and early development and for supporting fisheries conservation and ecosystem-based coastal management.

Assessment of Pest Pressure and the Severity of Attacks by Rice (Oryza sativa L.) Insect Pests in the Maniema Production Basins, Democratic Republic of the Congo

Adiyo Sumbu Henriette — 2026-08-28

Rice (Oryza sativa L.) production in the Democratic Republic of the Congo faces significant biotic constraints, particularly attacks by insect pests that hinder yield stability.

Aims: To evaluate the spatial variability of agro-morphological traits, pest pressure, and the severity of damage caused by insect pests to rainfed rice (Oryza sativa L.) across major production basins in Maniema Province, Democratic Republic of the Congo, to inform targeted integrated pest management strategies.

Study Design: A multi-site comparative field evaluation combining agro-morphological measurements with a quantitative phytosanitary diagnosis.

Place and Duration of Study: Agricultural fields across the production basins of Kailo, Kasongo, and Kibombo, Maniema Province, Democratic Republic of the Congo, during the crop maturity phase.

Methodology: A two-stage stratified sampling scheme was implemented across 384 rice fields (128 per basin), with 10 randomly selected plants evaluated per field (N = 3,840 plants). Recorded agronomic parameters included plant height, collar diameter, tiller count, and panicle grain load. In situ visual counts were used to assess pest abundance, infestation rate, and attack incidence. Qualitative canopy sweep sampling (n = 176) was used to identify pest taxonomic structure. Foliar and panicle attack severity were scored on a 0–9 scale to compute McKinney’s severity index (I_s). Data were analysed using ANOVA, Tukey’s HSD test, Pearson’s chi-square (χ2) test, and ecological diversity indices in R.

Results: Plant height was homogeneous across basins (1.25 to 1.31 m; p = 0.0351), whereas collar diameter, tiller count, and grain load showed significant spatial variation (p < 0.001). Orthoptera dominated the entomofauna (60.80%), led by Oxya hyla (31.25%), followed by Hemiptera (15.34%). Kailo achieved the highest grain load (139.13 ± 23.92 grains/panicle) but had high grain damage (3.66 ± 1.72 grains/sample). Kibombo emerged as the primary epidemic hotspot, exhibiting the lowest Pielou evenness (J’= 0.68), the highest mean pest abundance (1.16 ± 1.46 ind./plant; p = 8.37 times 10-13), a 57.97% infestation rate, 88.05% attack incidence, and an alarming McKinney index of 53.03% (compared to 18.05% in Kailo and 20.56% in Kasongo).

Conclusion: Entomological pressure and damage severity in rainfed rice are highly spatially dependent in Maniema. Kibombo requires urgent, localised intervention focusing on cultural controls and targeted biopesticides during tillering, whereas Kailo requires monitoring against sucking pests during grain filling.

Length-weight Relationship and Condition Factor of Labeo rohita (Hamilton, 1822) and Oreochromis mossambicus (Peters, 1852) Reared in a Floating-Raft Aquaponics System

Vikas Kumar Ujjania — 2026-09-03

Aims: To evaluate and compare the length-weight relationship and modified condition factor of rohu (Labeo rohita, T₁) and Mozambique tilapia (Oreochromis mossambicus, T₂) reared in a floating-raft aquaponics system.

Study Design: Comparative experimental evaluation of biometric performance and body condition of two fish species under floating-raft aquaponics conditions.

Place and Duration of Study: Research Laboratory (Wet Lab), Department of Aquaculture, College of Fisheries, Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan, India, for 60 days.

Methodology: One hundred fingerlings of each species were stocked separately in 400-L fibre-reinforced plastic tanks integrated with tomato (Solanum lycopersicum) saplings on floating rafts. Total length and body weight were recorded to establish the length–weight relationship using the power function W = aLᵇ. The coefficient of determination (R²) and regression coefficient (b) were estimated through log-transformed linear regression, and the modified condition factor (K) was calculated from the estimated b value.

Results: A positive length–weight relationship was observed in both species. The coefficient of determination was higher in L. rohita (R² = 0.8554) than in O. mossambicus (R² = 0.7432), indicating a stronger length–weight association in rohu. The b values were 1.9681 and 1.8742, respectively, indicating negative allometric growth in both species. The relationships were statistically significant (p < 0.05). The modified condition factor was higher in L. rohita (2.94) than in O. mossambicus (1.95).

Conclusion: Both species performed satisfactorily under the tested floating-raft aquaponics conditions, with L. rohita showing a stronger length–weight relationship and higher modified condition factor than O. mossambicus. These findings demonstrate the feasibility of rearing both species in floating-raft aquaponics, with rohu exhibiting comparatively better biometric performance.

Spatio-Temporal Assessment of Built-Up Expansion in Ghaziabad District, India Using the Normalized Difference Built-up Index (NDBI)

Sadaf — 2026-09-04

Background: Urbanisation in developing countries has considerably changed land surfaces, including through urban expansion and its effects on natural landscapes.

Aims: The present study investigates the spatial distribution and temporal variation of built-up regions.

Study Design: The Normalized Difference Built-up Index was used to map and quantify the spatial distribution and temporal variation of built-up spaces.

Place and Duration of Study: The NDBI was used to analyse spatio-temporal changes in urban expansion in Ghaziabad district, Uttar Pradesh, India, using multi-temporal Landsat imagery from 2013, 2018, and 2023.

Methodology: The Normalized Difference Built-up Index was used to assess built-up expansion in Ghaziabad district. To create NDBI maps and examine built-up growth trends, the satellite imagery was pre-processed and analysed using geospatial techniques.

Results: The findings show that substantial urbanisation occurred over the study period, especially in the vicinity of the main transport corridors and fast-growing urban and peri-urban centres. Urbanisation was associated with increased infrastructure development and land-use change, leading to declines in open space and cultivated land. The built-up space increased from 639.12 km² in 2013 to 678.70 km² in 2018 and further to 683.96 km² in 2023. Correspondingly, the number of built-up pixels increased from 710,134 in 2013 to 754,106 in 2018 and 759,961 in 2023. The total built-up space increased by 44.84 km² (7.02%) during 2013–2023, with an increase of 39.57 km² (6.19%) between 2013 and 2018 and 5.27 km² (0.78%) between 2018 and 2023.

Conclusion: The results offer important insights into the dynamics and intensity of urban expansion and may inform sustainable urban development, land management, and environmental protection in fast-growing areas.

Growth and Phenological Responses of Rice to Artificial Light at Night

V. P. Karthika — 2026-09-07

An experiment was undertaken at the Regional Agricultural Research Station, Pilicode, to study the effects of artificial light at night (ALAN) on the growth and phenology of rice. The experiment was laid out in a split-plot design, in which the absence and presence of artificial night illumination were considered main-plot treatments and five rice varieties, viz. ‘Rakthashali’, ‘Karuthanjavara’, ‘Chempav’, ‘Uma’ and ‘Jeerakasala’ were used as subplot treatments. Biometric observations were recorded on plant height, tiller number and panicle number. Crop phenological observations, such as duration to booting, heading and maturity, were also noted. The experiment was conducted over two seasons, and in both seasons, the variety ‘Karuthanjavara’ remained in the vegetative stage throughout the experimental period. Although ‘Chempav’ and ‘Jeerakasala’ reached the heading stage, they failed to achieve proper grain filling and did not produce quality seeds. In general, ALAN considerably increased the number of days required to reach the booting stage and extended the total crop duration, while reducing the duration from heading to harvest maturity compared to the non-ALAN-exposed plots. Among the five varieties evaluated, only ‘Rakthashali’ and ‘Uma’ produced harvestable grains under ALAN stress, although their crop duration was longer. ALAN also adversely affected early vegetative growth, resulting in reduced plant height and lower tiller production. One month after transplanting, the mean plant height in the ALAN-exposed main plot was 70.1 cm in autumn and 93.9 cm in summer, compared to 84.7 cm and 98.0 cm in the non-ALAN-exposed main plot. Similarly, the mean number of tillers in the ALAN-exposed plot was 6.4 in autumn and 17.9 in summer, whereas the non-ALAN-exposed plot recorded 15.5 and 28.4 tillers, respectively. In addition, panicle production was lower in the ALAN-exposed plots than in the non-ALAN plots. The ALAN-stressed main plot produced 23.4 panicles in autumn and 17.7 in summer, whereas the non-ALAN-exposed plot recorded 34.4 and 20.7 panicles, respectively. The study revealed that certain rice varieties are sensitive to extended photoperiods and confirmed that the transition from the vegetative to the reproductive phase in rice requires exposure to short-day conditions and relatively longer nights. This research highlights the negative impact of ALAN on rice growth and phenology. Even if improved cultivars tolerate minor night-light stress, extended exposure disrupts flowering schedules, grain filling and total yields in rice-based cropping systems.

Evaluation of the Physicochemical and Microbiological Quality of Borehole Water in the Urban Areas of Muzaffarpur, Bihar, India

Noor Fatma — 2026-09-08

This study evaluated the physicochemical and microbiological quality of borehole water during the post-monsoon period in Mushahari Block, Muzaffarpur, Bihar. Water samples were collected from 15 sites representing slum, residential, and industrial areas and analysed using standard APHA and BIS methods. The assessed parameters included pH, electrical conductivity, total dissolved solids, turbidity, total hardness, alkalinity, major ions, selected trace elements, and total coliforms. The borehole water was neutral to mildly alkaline, with pH values of 7.25–7.61. Total dissolved solids ranged from 466 to 1046 mg/L, while total hardness ranged from 308 to 520 mg/L, indicating substantial mineralisation and hardness. Calcium, magnesium, and alkalinity were also elevated at several sampling locations. Iron and nitrate represented the principal chemical concerns, with mean concentrations of 1.99 mg/L and 71.21 mg/L, respectively, and multiple samples exceeding BIS limits. In contrast, chloride, sulphate, fluoride, arsenic, and manganese remained within the applicable permissible limits. Total coliforms were detected in 6 of the 15 samples, demonstrating localised microbiological contamination. Overall, the observed groundwater quality reflects both geogenic and anthropogenic influences. The findings indicate that treatment, sanitary protection of water sources, improved waste-management practices, and regular monitoring are necessary before the borehole water is considered suitable for safe domestic use.

Assessment of Wetland Functional Responses to Cyperus papyrus Vegetation Biomass Harvesting Using Water Physicochemical Parameters and Macroinvertebrate Diversity in Saf Wetland, Kenya

Robert Juma Ogolla — 2026-09-09

Papyrus (Cyperus papyrus) is the dominant plant species in the floodplain and littoral wetlands of Lake Victoria, where harvesting by riparian communities may affect plant growth and wetland ecosystem functioning. This study evaluated wetland functional responses to papyrus harvesting by integrating surface-water physicochemical parameters with macroinvertebrate diversity metrics. A controlled factorial field experiment compared plots harvested frequently (monthly), moderately (every 2.5 months), and infrequently (every 3.5 months) with adjacent unharvested controls. Water temperature (WT), dissolved oxygen (DO), and electrical conductivity (EC) were measuredin situ, while triplicate samples were collected for total nitrogen (TN), total phosphorus (TP), and macroinvertebrate analyses. Data were analysed using robust two-way ANOVA in R (v4.6.0) because of heterogeneity and unequal sample sizes. Significant spatial variation was detected for EC (F = 12082.6, p = 0.001), WT (F = 31.168, p = 0.001), TN (F = 241.79, p = 0.001), and TP (F = 11.687, p = 0.006). Harvesting treatment did not significantly affect DO, EC, WT, TN, or TP. However, macroinvertebrate diversity was significantly affected by treatment (F = 4.766, p = 0.035), plot (F = 12.184, p = 0.005), and their interaction (F = 12.726, p = 0.004). Saf Wetland therefore maintained relatively stable physicochemical conditions after harvesting, although harvesting intensity influenced nutrient dynamics and macroinvertebrate diversity. Regulated harvesting is important for sustaining wetland ecological integrity and ecosystem-service provision in Lake Victoria papyrus wetlands.

Pharmaceutical Contaminants in Aquatic Environments: A Critical Synthesis of Sources, Ecological Risks and Bioremediation Strategies

Yogita Basene — 2026-08-28

Pharmaceutical residues are now routinely detected in wastewater-impacted aquatic environments because medicinal compounds and their metabolites enter sewerage, industrial effluents, agricultural drainage and receiving waters through multiple, often continuous pathways. Their environmental significance cannot be inferred from occurrence alone: risk depends on potency, exposure duration, mixtures, transformation products, species sensitivity and the capacity of treatment systems to reduce biologically active mass. This critical narrative review integrates evidence on sources, ecological effects and bioremediation, with emphasis on wastewater-impacted freshwaters and on technologies that rely substantially on microbial, fungal, algal or plant-associated processes. Literature was selected through live searches of multidisciplinary and environmental or biomedical scholarly sources, supplemented by citation searching and DOI verification. The strongest causal ecological evidence comes from whole-ecosystem work with endocrine-active pharmaceuticals, while laboratory and field studies also support concern for behavioural disruption, chronic sublethal effects and antibiotic-driven selection for antimicrobial resistance. Nevertheless, extrapolation remains difficult because monitoring is dominated by parent compounds and targeted analytes, whereas mixtures and transformation products are incompletely characterised. Conventional activated sludge provides variable and compound-specific attenuation; apparent parent removal may reflect sorption or transformation rather than mineralisation. Membrane bioreactors, adapted bacterial consortia, white-rot fungi, microalgae and constructed wetlands can improve removal under favourable conditions, but evidence is uneven across scales and frequently relies on high test concentrations or parent disappearance. The synthesis indicates that no single biological technology provides universal control. Risk reduction is more defensibly pursued through source control, robust biological treatment and targeted polishing, supported by mass balances, transformation-product screening, effect-based endpoints and antimicrobial-resistance assessment. Future research should prioritise trace-level, full-scale comparisons and standardised demonstrations that connect chemical removal to reduced biological hazard.

New Additions to the Flora of Orissa: An Updated Checklist on New Distributional Records of Plant Species to the State of Odisha from 1996 Onwards- A Literature Synthesis

Nabin Kishore Jena — 2026-09-10

Among the eastern Indian states, Odisha plays a vital role in the study of floristic diversity due to its unique geographical location, variation in geological factors, and diversity in floristic composition. The monumental work of H. O. Saxena & M. Brahmam during 1994-1996 documented a total of 2,727 species in the Flora of Orissa. In the present review, an attempt has been made to prepare a database of new distributional records of plant species in the flora of Odisha from 1996 onwards. To compile a comprehensive account of new distributional records, literature from the last 30 years (1996-2025) was searched in databases such as Google Scholar, ResearchGate, Wiley Online Library, JSTOR, Scopus, and Springer Nature using keywords such as “new additions to the flora of Odisha”, “new distributional record to Odisha flora”, “new records to the flora of Odisha”, “new records to Eastern Ghats”, and “note on the identity”. In addition, herbarium consultations were conducted at CSIR-IMMT, Bhubaneswar, RPRC-Bhubaneswar, and CNH-Kolkata. A total of 176 papers were accessed, of which 165 provided information on new distributional records of 222 plant species belonging to 71 families during the last three decades; consequently, the documented plant species composition has been updated to 2,949. Among the recorded plants, angiosperms were dominant, with 209 species (147 dicotyledons and 62 monocotyledons), followed by 11 pteridophytes in 5 families and 2 gymnosperms in 1 family. The authors of these studies deposited herbarium specimens in the herbaria of CNH, RPRC-Bhubaneswar, Utkal University, MSCB University, Berhampur University, RRL-B, CSIR-NBRI, and NBPGR. This literature synthesis serves as reference material for policymakers and conservation biologists regarding habitat protection and species conservation.