Reproductive biology of the protandric hermaphrodite fat snook Centropomus parallelus Poey 1860 in a tropical estuary, northeastern Brazil

Reproductive biology of the fat snook Centropomus parallelus Poey, 1860 (Teleostei, Centropomidae) and implications for its management in the southern Atlantic Ocean

“…Considering the parameters (relative frequency of reproductive stages and gonadosomatic index) used to determine the reproductive period, results indicated that the reproductive activity of C. parallelus occurs during the austral spring and summer (from September to March) (Figure 1a), confirmed by histological indicators of eminent spawning (e.g., late germinal vesicle breakdown, hydration and postovulatory follicle). The co-occurrence of different oocyte development stages was similar to those described for Centropomus medius (Maldonado-Garcia et al, 2005), C. undecimalis (Peters et al, 1998) and C. parallelus (Assis et al, 2019;Chaves & Nogueira, 2019), thus confirming the group synchronous development and multiple spawning pattern (Figure 1b). The individual in sexual transition showed residual male tissue (secondary spermatogonia) oocytes in primary growth phase (Figure 1c), supporting previous studies that demonstrate protandric hermaphroditism in fat snook.…”

“…Assis et al . (2019) reported a significantly earlier onset of sexual maturity for males (141 mm) from a tropical estuary in the north‐eastern region, whereas Chaves and Nogueira (2019) recorded higher values of L 50 for males (194.7 mm) in Guaratuba bay during 2007/2008, in southern Brazil. The size at sexual maturity of females showed values slightly different among studies: 224 mm (Assis et al ., 2019) and 200.4 mm (Chaves & Nogueira, 2019).…”

“…The proportion of males was higher than females in the 132–290 mm L T classes (χ 2 = 4.79, P < 0.05), whereas females outnumbered males in all L T classes >291 mm (χ 2 = 4.59, P < 0.05), suggesting a protandrous hermaphroditism pattern (Table 1). Overall sex‐ratio did not differ significantly (χ 2 = 1.07, 1.23 females:1 male, P > 0.05), however the sex‐ratio was slightly biased towards females (median of the distribution of females' proportion 0.445) when compared with the estimates provided in the literature (Santos, 2014; Chaves & Nogueira, 2019; Assis et al ., 2019) through a conjugate beta‐binomial model (Gelman et al ., 2004).…”

Maturation of female common snook Centropomus undecimalis: implications for managing protandrous fishes

“…At 7.4 years, 93%–96% of females were mature. Similarly, the length at maturity ( L 50 ) based on sex ratios has been found to be higher than that based on female maturity in such protandric species as fat snook Centropomus parallelus (Poey 1860) (de Assis et al ., 2019) and striped sea bream Lithognathus mormyrus L. (Kallianiotis et al ., 2005). In the present study, A 50 based on proportions of mature and immature females was 4.1–4.9 years, suggesting that female fish are contributing to the population as females 2–3 years earlier than had been presumed based on sex ratios.…”

“…Assessing hermaphroditic species is a challenge because of age and length‐specific sex ratios that vary as a result of differential fishing and mortality (Provost & Jensen, 2015). For protogynous species, various methods have been suggested for treating sex change in stock assessments ( e.g ., Provost & Jensen, 2015), but too little attention has been paid to the problem in protandrous species (but see Taylor et al ., 2000; Kallianiotis et al ., 2005; Novoa‐Pabon et al ., 2015; de Assis et al ., 2019). The present study addresses this lack of attention by describing an immature female phase in a protandrous hermaphrodite, thus disproving a commonly held assumption, and by demonstrating how the inclusion of the immature female phase may impact the calculations of basic life‐history parameters such as age at maturity.…”