International Journal of Fisheries and Aquatic Studies 2015; 2(6): 391-394 Determination of Seasonal Cyclicity of Gonad by Studying Its Histology during Pre-Spawning and Spawning Period of Anabas testudineus (Bloch) In Natural Environment release_va6yh47pfrc3zknhxjeuhcsjmm

Abstract

The present study attempts to understand the histology of gonads of Anabas testudineus (Bloch) collected from natural environment of Mohanpur in West Bengal. From the study of histological characteristics the gonadal cycle of A. testudineus was found in preparatory phase and spawning phase. During January to February, tunica albuginea was thick and seminiferous lobules were not dense and less spermatogenic activity was seen. During this period, primary and secondary spermatogonia are visible. Histological observations revealed that testicular and lobular wall were thin. The lobules were filled with spermatozoa and sperm cells. During January and February, more number of immature oocytes stages like stage I, stage II and stage III are observed. This stage was characterised by the formation of minute yolk vesicles (early yolk vesicles) in the peripheral ooplasm. In the oocytes, at late perinucleolus stage the oocytes were observed with increased ooplasm. During March to June, the ovaries were very much enlarged and reached their maximum size and occupied the whole body cavity. In this phase, the ovarian wall became thin and the oocytes of late yolk vesicle stage and early yolk stage were found more in number than the late perinucleolus stage and early yolk vesicle stage. During this period, the oocytes showed an increased in size and ovaries are filled with ripe eggs.
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