Ovarian Development and Sex Steriod Hormones in the Keeled Fish <i>Liza carinata</i> (Valenciennes, 1836) From Suez Bay, Egypt

The reproductive biology and sex hormones of the rabbitfish (Siganus rivulatus) in the Suez Gulf

“…In a variety of species, the level of serum E2 begins to increase in accordance with the appearance of active maturing gonad, and reaches the highest levels at ripe stage in the ovary, and sharply declines in fish with spent gonad. (Smith Haley, 1988;Silvers et al, 1993;Kumar et al, 2015;Hefny et al, 2016 andPouresmaeilian et al, 2017) reported an increase in plasma E2 levels once spawning commences and remains high throughout the period of gonad growth.…”

“…Of these steroids, 17-β estradiol (E 2) stimulates in turn the hepatic synthesis and secretion of vitellogenin which is accumulated in the gonad. Correlations between changes in plasma levels of gonad steroids and oocyte development have been well documented in a number of freshwater species including Salmon forms (Whitehead et al, 1983 andTruscott et al, 1986), Cyprinids (Kobayashi et al, 1987), catfish Heteropneustes fossilis (Lamba et al, 1983), goldeye Hiodon alosoides (Pankhurst et al, 1986), walleye Stizostedion vitrum (Malison et al, 1994), and marine species including orange roughly Hoplostethus atlanticus (Pankhurst & Conroy, 1988;Bariche et al, 2003), Japanese whiting Sillago japonica (Matsuyama et al, 1990), Japanese sardine Sardinops melanostictus (Matsuyama et al, 1991), Common snook Centropomus undecimalis (Roberts et al, 1999), Caspian kutum (Sabet et al, 2009), catfish Hemibagrus nemurus (Adebiyii et al, 2013) and Liza carinata (Hefny et al, 2016). Fish have evolved to reproduce under environmental conditions that are favorable to the survival of the young.…”