Ovarian histology of the freshwater catfish (Hamilton, 1822).

Histological characterization of gonadal tissues and their development can divulge vital clues to interpret the onset and progression of the spawning period in fish species and help in wild stock augmentation to conserve the natural fish stocks. In the present study, ovarian histology of female was investigated from the Kangsha River, Bangladesh from March to November 2018. During this investigation, 54 females of was analyzed to study the ovarian development. The histological evaluation revealed five distinct stages of gonadal development (Immature, Developing, Spawning capable, Regression or spent and Regeneration or Re-developing). Six phases of oocyte development were further characterized during the gonadal development stages as under-developed, primary growth, cortical alveolar, vitellogenic, pre-mature, and mature stage. In conclusion, the gonado-somatic index and histological analysis of ovaries indicated that the peak spawning of occurs in July, and suggesting that the studied fish spawns once per breeding season. The present study recommends year round investigation of gonadal cycle and gonad developmental study of male individuals of .