Effect of lead nitrate on the ovaries of the - striped snakehead Channa striatus (Bloch, 1793)

The effect of sublethal concentrations of lead nitrate (0, 8, 18 and 28 mg l-1) on the ovaries of the freshwater murrel Channa striatus (Bloch, 1793) (average length : 20-25 cm; average weight : 50-60 g), randomly distributed (ten fishes per group) into four groups (control, Exp-1, Exp-2 and Exp-3, respectively), were studied in triplicate. Each group of fishes were exposed to lead nitrate for 90 days with the aim to assess the histoarchitectural alterations in the ovaries, at different time intervals. Loosening of connective tissue, deshaped primary oocytes, damaged epithelial layer of oocytes, decreased number of yolk granules in secondary oocytes, upliftment of epithelial layer of secondary oocytes, comparatively decreased number of primary oocytes, necrosis, damaged and irregular shaped oocytes and inflammation were common features in all the three experimental groups exposed to sublethal concentrations of lead nitrate. Severity of the above features increased with increased lead nitrate concentration and duration of exposure.

Reproductive biology of the freshwater murrel Channa punctatus (Bloch, 1793) from River Gomti of Lucknow region, Uttar Pradesh, India

A total of 187 samples of Channa punctatus (Bloch, 1793) from River Gomti of Lucknow region, Uttar Pradesh were studied during 2011. The sex ratio of 1: 0.84 was not significantly different from 1:1. Monthly variation in the gonadosomatic index (GSI) and maximum number of stage IV gonads encountered in the months of May to August indicated that the spawning season extends for about 4 months and spawning was high during the monsoon season. Absolute fecundity varied from 11000 to 28000, with an average value of 14920. Fecundity was found to be highly correlated to the total length (r = 0.9201), body weight (r = 0.9133) and weight of ovary (r = 0.8536) with all correlation coefficients being highly significant (p<0.0001). Total length (TL) of fish and weight of the ovary also highly correlated (r = 0.9551, p<0.0001). This study provides primary information on reproductive parameters of C. punctatus from River Gomti which can be utilised for management of the resource.

Phenotypic Variation in Freshwater Murrel,Channa punctatus(Bloch, 1793) from Northern and Eastern Regions of India Using Truss Analysis

Morphometric variation study was carried out using truss analysis in freshwater murrel,Channa punctatus(Bloch, 1793), to explore different phenotypic stocks ofC. punctatus.Significant variation in the morphometric analysis was observed using the truss network and multivariate analysis of the three subpopulations of freshwater murrel,C. punctatus, from the two different regions of India. Principal component analysis accounted for a total variation of 91.95% by the first three principal components. PC 1 represented the variation due to size and PC 2 and PC 3 represented variations due to shape. The 95% confidence ellipses depicted the clear isolation between the samples in scatter graph of PC 1 on PC 2. The combined groups plot (DF 1 on DF 2) based on discriminant function analysis (DFA) also validated the existence of three different subpopulations. In group classification using DFA, 100 percent of all the samples were correctly classified into their original subpopulation. These results support the existence of multiracial composition ofC. punctatusacross the different geographical isolated sites and, thus, these findings indicate the presence of three different phenotypic stocks ofC. punctatus.