Seasonal reproductive cycle of Waigieu seaperch (Psammoperca waigiensis)

Abstract

Predictive and reliable parameters of reproductive status are integral aspects of sustainable fisheries and aquaculture management. These parameters are also important for an accurate evaluation of the effects of different treatments on sexual maturation in fish farming. In the present study, we have characterized the seasonal reproduction profile and described changes in sex steroids in relation to gonadal maturation and development in female and male Waigieu seaperch (Psammoperca waigiensis). The experimental period covered a full calendar year (January–December). In males and females, we observed that plasma sex steroid hormones [oestradiol-17β (E2), testosterone (T), 11-ketotestosterone (11-KT) and progesterone (P)] levels showed monthly fluctuations during the spawning period. Particularly, plasma steroid hormone levels were positively associated with gonadosomatic index values. In addition, high levels of plasma steroid coincided with recruitment of oocytes into yolk accumulation in females. The main spawning period occurred between April and October in females, and between March and November in males. The non-aromatizable androgen, 11-KT is generally believed to be the active male-specific androgen in teleosts, and is associated with the process of spermiation, development of secondary sexual characteristics and regulation of male reproductive behaviour in most teleost species. In this study, we found relatively high amounts of 11-KT in females between May and December, suggesting an integral role in the maturation process, also for the females. A rapid peak in plasma P level was observed in November and suggests significant roles during post-spawning and/or resting periods in both female and male fish. Furthermore, all oocyte developmental stages were present within the same sampling month and also within the spawning period, demonstrating the gamete group asynchronous developmental strategy. Overall, Waigieu seaperch showed strong seasonality in reproductive development with corresponding sex steroid patterns. The data presented in this study may contribute to the understanding of the reproductive endocrinology of a tropical marine finfish with increasing industrial prospects and sustainable aquaculture of this species in a developing country, such as Vietnam.