GnRHa-induced spawning of wild-caught spotted rose snapper Lutjanus guttatus

Dose-dependent effect of a single GnRHa injection on the spawning of meagre (Argyrosomus regius) broodstock reared in captivity

“…Optimal GnRHa doses have also been found in similar studies on sea bass (Lates calcarifer) (Garcia, 1989), gilthead seabream (Sparus aurata) (Barbaro et al, 1997) and spotted rose snapper (Lutjanus guttatus) (Ibarra & Duncan, 2007). It has been demonstrated that GnRHa stimulates spawning in fish with arrested maturation by releasing LH from the pituitary, which in turn stimulates oocyte maturation and the fish to spawn (Zohar et al, 1995;Mañanos et al, 2002;Podhorec et al, 2012).…”

“…Duncan et al (2012) and Mylonas et al (2013a) measured oocyte diameter immediately before hormone application. Stress is accepted as one of the principal factors that cause reproductive dysfunctions and that affect a GnRHa spawning protocol (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010). For example, the stress of capture has been shown to negatively affect reproductive endocrinology, decreasing estrodial and testosterone and oocyte development increasing oocyte atresia in red gurnard (Chelidonichthys kumu) (Clearwater & Pankhurst, 1997), female striped trumpeter (Latris lineate) (Morehead, 1998) and snapper (Pagrus auratus) (Cleary et al, 2000).…”

“…The Gaussian regression analysis of egg and larval quantity or yield indicated that 15 µg kg -1 was the optimal dose applied; where significant differences were observed the 15 µg kg -1 dose exhibited a significantly higher number of eggs and larvae and a significantly higher percentage of egg viability and generally the highest egg quantity (number of eggs and larvae), the highest egg quality (fertilization, viability and hatching); and highest larval quality (larvae with reabsorbed yolk sac) were obtained from the broodstock treated with the 15 µg kg -1 dose. It has been indicated that the aspects to be considered in the development of a GnRHa induced spawning protocol are: (a) stage of ovarian development measured as oocyte diameter (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010), (b) levels of stress related to husbandry and manipulations to administer the GnRHa (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010) and (c) the GnRHa dose (Ibarra & Duncan, 2007;Mañanos et al, 2008). The GnRHa protocol should identify a minimum oocyte diameter that needs to be attained or surpassed by the maturing fish before successful spawning can be obtained with the administration of GnRHa (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010).…”

“…It has been indicated that the aspects to be considered in the development of a GnRHa induced spawning protocol are: (a) stage of ovarian development measured as oocyte diameter (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010), (b) levels of stress related to husbandry and manipulations to administer the GnRHa (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010) and (c) the GnRHa dose (Ibarra & Duncan, 2007;Mañanos et al, 2008). The GnRHa protocol should identify a minimum oocyte diameter that needs to be attained or surpassed by the maturing fish before successful spawning can be obtained with the administration of GnRHa (Ibarra & Duncan, 2007;Mañanos et al, 2008;Mylonas et al, 2010). In the present study, oocyte diameter was >0.5 mm in all female meagre at the start of the experiments and 89% of females treated spawned at least once indicating that the minimum required oocyte diameter was surpassed and was not a factor that affected spawning success.…”

Effects of temperature and salinity on growth and survival of the Pacific red snapper Lutjanus peru (Pisces:Lutjanidae) juvenile

“…Ibarra-Castro & Duncan (2007) detailed the commercial importance of snapper species, and other authors have explained the interest of aquaculture and fishing industries in developing snapper culture (Tucker & Jory, 1991;Leu et al, 2003;Dumas et al, 2004;Ogle & Lotz, 2006;Boza-Abarca et al, 2008;Castillo-Vargasmachuca et al, 2007;Boza-Abarca et al, 2011;CastilloVargasmachuca et al, 2012;Alvarez-Lajonchere et al, 2012). Growing this species in cage protected sites or open sea (Bergheim, 2012) and ponds on land has been considered as a future possibility.…”