Anish Dua

Comparative morphometrics of two populations of giant river catfish (Mystus seenghala) from the Indus river system

Giant river catfish (Mystus seenghala) from the Beas river were compared with a population in the Sutlej river of the Indus river system using 28 morphometric characters. Discriminant analyses and a univariate anova were used to explore these data. Allometric transformation of each measurement was done to eliminate correlations with size. The stepwise discriminant analysis retained nine variables that significantly discriminated the Beas samples from the Sutlej samples. Using these variables, 91.2% (original) and 89.0% (cross validated) of fish were classified into their correct samples. Misclassification was higher for the Sutlej samples (12.5%) than for the Beas samples (6.3%). The results of the discriminant analyses showed that variability in the Beas samples was more homogeneous and provided a more characteristic picture of the group than the Sutlej samples. The univariate ANOVA revealed significant differences between the means of the two populations for 12 of the 28 transformed morphometric measurements.

Scales of Freshwater Fish Labeo rohita as Bioindicators of Water Pollution in Tung Dhab Drain, Amritsar, Punjab, India

This study examined the impact of municipal wastewater on scale morphology of freshwater fish Labeo rohita. Fish were exposed to sublethal concentrations (17.7, 26.6, or 35.4%) of municipal wastewater for durations of 15, 30, and 60 d. Recovery experiments were also performed for a duration of 60 d. Scales were extracted after respective exposure periods, cleaned, and processed for scanning electron microscopy. Results showed concentration- and exposure duration-dependent alterations in the morphology of scales. Severe damage was observed at the anterior and posterior portions of scales in the form of lepidontal breakage and uprooting, destructions at the base of circuli and radii along with complete structural loss in the focal region and adjacent circuli and radii, and alterations in structure of tubercles. Data indicate that scales of fish L. rohita may be employed as bioindicators of water pollution and could be incorporated into water monitoring surveillance.

Genetic variability analysis of Giant river cattish ( Sperata seenghala ) populations from Indus river system by RAPD-PCR

The Giant river catfish, Sperata seenghala (Sykes) is commercially very important fish species of South Asia. Genetic variability between its populations collected from two rivers i.e. river Sutlej and river Beas of Indus river system in India were examined using randomly amplified polymorphic DNA analysis. Total 38 fish samples were collected from river Sutlej whereas 46 fish samples were collected from river Beas. Total 40 primers were screened, out of these 7 were selected for studying polymorphism which produced a total of 64 RAPD loci in two populations. Percentage polymorphic loci calculated following 95% criterion was 89.06 % for Beas population as compared to 95.31 % for Sutlej population. Moderate level of genetic divergence (genetic distance of 0.0486) between both the populations suggests distinct population substructure of giant river catfish in both the rivers.

Colour changes in Labeo rohita (Ham.) due to pigment translocation in melanophores, on exposure to municipal wastewater of Tung Dhab drain, Amritsar, India

The present study was aimed to evaluate the effect of municipal wastewater of Tung Dhab drain on morphology of scale melanophores in freshwater fish Labeo rohita (Ham.). Chronic, non-renewal toxicity tests were performed with sub lethal concentrations (17.7, 26.6 and 35.4%) of wastewater for exposure durations of 15, 30 and 60 days. Recovery experiments were also performed for duration of 60 days. The scales were removed, processed and diameters of melanophores were measured using an ocular micrometer. The results showed concentration and duration dependent changes in melanophore morphology (size and dendricity) in experimental fish as compared to control fish. The values of mean melanophore size index (MMSI) varied from 5.37 ± 0.49 (17.7%) to 12.12 ± 0.81 (35.5%) in comparison to control values of 4.32 ± 0.32 and 4.55 ± 0.29 for 15 and 60 days respectively. The recovery experiments suggested that observed dark colouration due to pigment translocation is reversible, even after chronic exposure for 60 days.

Municipal wastewater-induced histopathological lesions in gills of freshwater fish Labeo rohita – A SEM study

The fingerlings of fish Labeo rohita were subjected to chronic (15, 30, and 60 days) and recovery (60 days) experiments for histopathological studies using sublethal concentrations (35.4%, 26.6%, and 17.7% v/v) of municipal wastewater of Tung Dhab drain, Amritsar, India. Control fish were maintained for same exposure periods using tap water. Scanning electron microscopic studies exhibited dose- and duration-dependent alterations on gill surface ultra-structure. Control fish exhibited functionally normal gills with normal mean degree of tissue change. Fifteen different types of lesions were identified out of which 9, 5, and 1 were of the stage I, II, and III, respectively. The mean degree of change values in the treated groups ranged from 14.8 ± 0.5 (17.7%, 15 days) to 116. ± 17 (35.4%, 60 days) demonstrated gill damages of slight to irreparable lesions. The recorded alterations were epithelial lifting and intraepithelial edema, reduction of water spaces, lamellar fusion, lamellar telangiectasia, swelling and fusion of filaments, sloughing of lamellar epithelium, hypertrophy and hyperplasia of mucous and chloride cells, and necrotic lamellae. The recovery experiments showed positive improvement as the intensity of damage was less than recorded for 60 days of treatment. This study clearly indicated toxicity of drain water to fish at cellular and organ level. The study recommends environmental agencies to make and enforce decisions regarding improvement of water quality of Tung Dhab drain, and further incorporating histopathological studies as an analytical tool.

Assessment of Water Quality of Tung Dhab Drain—An International Water Channel—Using Multivariate Statistical Techniques

Different multivariate statistical techniques were applied to interpret the temporal variations in water quality of Tung Dhab drain, Amritsar, India and further to identify water pollution sources. Data was collected seasonally for a period of two years (2012-2013) using 34 water quality parameters. The recorded values for variables like turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand, oil & grease, nitrate as N, lead, chromium, nickel and zinc were much higher than the recommended permissible discharge limits into inland waters. Significant correlations were found in between different physicochemical parameters ( p ≤ 0.05; p ≤ 0.01). Cluster Analysis (CA) grouped four sampling seasons into two clusters. CA confirmed that the water quality of rainy season was different from other three seasons in terms of similarity and distance indices. Principal Component Analysis/Factor Analysis (PCA/FA) explained minerals, organic, agricultural and industrial pollutants responsible for deterioration of drain water quality. The present study will help environmental agencies to make and enforce decisions regarding improvement of water quality of Tung Dhab drain.