ABSTRACT This study describes the mechanism of reproduction control in the female blue gourami, Trichogaster trichopterus, as asynchronic (male dependent), multi-spawning fish. Two stages of oogenesis were observed: vitellogenesis, which was not male dependent, and maturation, which was controlled by male behavior. Before sexual behavior began, the oocytes were in vitellogenic stages and no mature oocytes were found. During nest building by the male, the oocytes underwent maturation and ovulation. The maturation of the oocytes and ovulation were related to male behavior and pheromones. Steroid glucoronides (fish pheromones) were detected in the gonads of males and females in the water in which the male had built the nest. This holding water effected oogenesis in the female and caused oocytes to mature. Levels of testosterone (T) and estradiol-17ß in females increased after spawning. 17-hydroproges terone remained low in both sexes, though it was detectable in the plasma of the female during spawning. The level of 17, 20ß-dihydroxy-4-pregnen-3-one was very low during the pre-breeding and nest-building periods; it rose significantly during spawning.
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