Histopathological Effects of Mercury on Male Gonad and Sperm of Tropical Fish Gymnotus carapo in vitroC. S. Vergilio, R. V. Moreira, C. E. V. Carvalho and E. J. T. MeloE3S Web of Conferences, 1 (2013) 12004DOI: https://doi.org/10.1051/e3sconf/20130112004