Dandadhar Sarma

Evaluation of genetic toxicity caused by acid mine drainage of coal mines on fish fauna of Simsang River, Garohills, Meghalaya, India

Fishery ecology of the Simsang River, Meghalaya is being threatened by large scale environmental degradation due to acid mine drainage (AMD) of coal mines. In the present paper, effort has been made to evaluate the genotoxicity caused due to AMD of coal mines on Channa punctata under laboratory condition through comet assay, micronucleus and chromosome aberration tests. Water samples were collected seasonally from affected and unaffected sites of the River and physico-chemical quality of water indicated low pH (4.6), high concentration of sulphates (270mgL(-1)) and iron (7.2mgL(-1)) beyond permissible limits. Polycyclic aromatic hydrocarbon (PAH) showed highest concentration of 4-ring PAH and Benzo[a]anthracene was the most important pollutant in the water collected from affected sites. The highest and the lowest mean concentrations of PAHs were estimated in monsoon and winter season, respectively. The index of DNA damage assessed by comet assay, micronucleus and chromosome aberration tests demonstrated significant differences season wise in different sampling sites. Frequency of DNA-damaged cells was found highest in the water samples collected from affected site in monsoon season.

The complete mitochondrial genome of threatened chocolate mahseer (Neolissochilus hexagonolepis) and its phylogeny

The chocolate mahseer (Neolissochilus hexagonolepis) is an important food and game fish of North Eastern India. To study the phylogenetic status we sequenced the complete mitochondrial genome of N. hexagonolepis. The mitogenome is 16,563 bp in length and composed of 13 protein coding genes, 22 tRNAs, 2 rRNAs and one putative control region. The overall base composition was A 31.8%, T 25.0%, G 15.8%, C 27.4% and A+T content 56.9%, G+C content 43.1%. The phylogenetic analysis using the complete mitochondrial genome revealed that the chocolate mahseer belonged to same clade of mahseer group of fishes but different from genera Barbus and Acrossocheilus. The present study will be helpful for the evolution and conservation genetic studies of N. hexagonolepis.

Cytotoxic and genotoxic affects of acid mine drainage on fish Channa punctata (Bloch)

The investigation deals with the effects of Acid Mine Drainage (AMD) of coal mine on fish Channa punctata (Bloch) by examining the incidence of haematological, morphological, histological changes and DNA fragmentation in tissues of C. punctata in laboratory condition. For this study fishes were exposed to 10% of AMD for a period of 30 days. The fusion of the primary and secondary gill lamellae, distortion, loss of alignment, deposition of worn out tissues and mucous on the surface of the lamella in the gills; degeneration of morphological architecture, loss of alignment of tubules, mucous deposition in the kidney; cellular damage, cellular necrosis, extraneous deposition on the surface, pore formation in the liver are some important changes detected by scanning electron microscopy. Fishes of AMD treated group showed gradual significant decrease in TEC, Hb and, increase in TLC and DLC as compared to that of the control. DNA fragmentation observed in kidney of fishes from treated group indicates an intricate pollutant present in the AMD. The high incidence of morphological and histological alterations, haematological changes along with DNA breakage in C. punctata is an evidence of the cytotoxic and genotoxic potential of AMD of coal mines.

Schistura larketensis , a new cavernicolous fish (Teleostei: Nemacheilidae) from Meghalaya, Northeast India

Schistura larketensis, a new species of cavernicolous loach, is described from Khung, a limestone cave in Meghalaya, India. The species differs from Schistura papulifera, its only troglomorphic congener from northeast India, in having a smooth ventral surface of the head, the presence of a small cylindrical axillary pelvic lobe, and the presence of three pores in the supratemporal canal of the cephalic lateral-line system. Apart from these differences, the species can be immediately distinguished from all other species of Schistura from the Brahmaputra River and neighboring basins by the complete absence (or only vestigial presence) of eyes.

Figure 6 In Schistura Larketensis, A New Cavernicolous Fish (Teleostei: Nemacheilidae) From Meghalaya, Northeast India

FIGURE 6. Lateral view of head showing gradual reduction and loss of eyes (black arrows) with increasing size in Schistura larketensis; a, paratype GUMF 0262/2, 45.1 mm SL; b, holotype, GUMF 0261, 54.5 mm SL; c, paratype GUMF 0263/2, 63.1 mm SL; d, paratype, GUMF 0263/2, 68.1 mm SL.Scale bar 1 mm; e,graphical representation of decreasing eye diameter (ED) with respect to increase in standard length (SL).

Karyology of Puntius sophore (Pisces, Cypriniformes) from theBrahmaputra River, Assam, India

In this investigation karyotypes of Puntius sophore from the Brahmaputra River (Assam, India) are presented. Chromosome preparations were made using anterior parts of the kidney cells. The karyotype of the population under study consisted of 48 diploid chromosomes with fundamental arm number 54. The chromosomal divergences in P. sophore with different ecology and geographical distribution are discussed.