Reproduction and embryogenesis

A molecular and ecological study of Grillotia (Cestoda: Trypanorhyncha) larval infection in small to mid‐sized benthonic sharks in the Gulf of Naples, Mediterranean Sea

“…Among the indices for evaluating the physiological condition of the fishes (GSI, HIS, and SMS), only GSI was a discrete predictor in S. canicula , with a value of 29.9%, while HSI (14.2%) showed lower relative importance (Figure 6c ). GSI is a good indicator of reproductive activity of fish, while the HSI is strictly related to the gonadal maturation and in general increases at early ripening and decreases at late ripening (Rizzo & Bazzoli, 2020 ). In the present study, most of the specimens of S. canicula were in reproductive activity (70.2%) suggesting that this physiological condition can modify the immune responsiveness increasing susceptibility to parasitic infections due to an increase in circulating levels of sex steroid hormones.…”

Benfotiamine in high carbohydrate diet enhances growth and reproductive performance of the Asian native catfish Clarias macrocephalus subadults

“…In fish, GSI has often been used to indicate relative gonadal development or activity (Rizzo & Bazzoli, 2020). In the present study, dietary benfotiamine resulted in significantly highest GSI values in male and female Asian catfish isometrically associated with body weight.…”

Seasonal morphophysiological changes during the reproductive cycle of the tripletail fish Lobotes surinamensis (Perciformes: Lobotidae) in the western South Atlantic

“…This points to an asynchronous oocyte development and consequently a multiple spawning. In males, the variation in GSI values during the reproductive cycle is more subtle among the different fish species studied (Helfman et al 2009;Nóbrega et al 2017;Rizzo and Bazzoli 2020), as also observed for L. surinamensis. In addition, the general characteristics of the testes of L. surinamensis followed the same anatomical and histological patterns as those of most teleosts (Parenti and Grier 2004;Rocha and Rocha 2006;Siqueira-Silva et al 2019;Rizzo and Bazzoli 2020).…”

“…In males, the variation in GSI values during the reproductive cycle is more subtle among the different fish species studied (Helfman et al 2009;Nóbrega et al 2017;Rizzo and Bazzoli 2020), as also observed for L. surinamensis. In addition, the general characteristics of the testes of L. surinamensis followed the same anatomical and histological patterns as those of most teleosts (Parenti and Grier 2004;Rocha and Rocha 2006;Siqueira-Silva et al 2019;Rizzo and Bazzoli 2020). Another parameter measured in fish reproductive biology is the L 50 index, that according to King (2007) is the mean length at first reproduction, or at sexual maturity, and may be defined as the length at which 50% of all individuals are sexually mature.…”

“…It was observed a variation from 1.19 ± 0.24 to 3.57 ± 0.37 in females and 0.13 ± 0.03 to 0.27 ± 0.02 in males for L. surinamensis. Despite that, the evaluation of ovarian morphology in L. surinamensis revealed the presence of different developmental phases of oocytes, with low GSI values compared to values obtained from synchronous spawners, which present higher GSI values (Tyler and Sumpter 1996;Rizzo and Bazzoli 2020). This points to an asynchronous oocyte development and consequently a multiple spawning.…”