GnRHa‐induced Multiple Spawns and Volition Spawning of Captive Spotted Rose Snapper, Lutjanus guttatus, at Mazatlan, Mexico

Abstract

Sexual maturation and induced spawning treatments were carried out with captive spotted rose snapper, Lutjanus guttatus. A total of 3013 × 10 6 eggs (64.7% were floating) were produced from eight treated females in 42 spawns induced with GnRHa implants during the course of the present study. GnRHa ethylene-vinyl acetate copolymer effective doses were 204 ± 11 μg/kg in June 2005, and 224 ± 13 μg/kg in July 2005. General fertilization was 50.9 ± 34.5% and 12-14 h after spawning, viability of floating eggs was 90.4 ± 12.4%. Mean incubation period at 29-31 C was 18-20 h, and mean hatching was 94.4 ± 8.2% (73-100%). Newly hatched larvae were 2.18 ± 0.15 mm in total length (TL). One month after the last hormone experiment, previously GnRHa-treated and untreated fish began spawning voluntarily. Hormone-treated breeders had higher fecundity than untreated fish, producing 72.5 million eggs versus 13.9 million eggs for the untreated fish, over the following 11 mo. Combined data of volitional spawning for total egg fertilization, viability, hatching, and larval TL were 77.7 ± 1.8%, 90.3 ± 1.3%, 87.9 ± 2%, and 2.50 ± 0.12 mm, respectively. These results can ensure the sustainability of a commercial hatchery.

The Scale‐up of Spotted Rose Snapper, Lutjanus guttatus, Larval Rearing at Mazatlan, Mexico

“…Eggs for this trial were chosen from a single night's spawning in the third month after the captive broodstock started natural spawning (Ibarra‐Castro and Alvarez‐Lajonchère 2011). A total of 480,000 eggs were collected from one spawning tank, 14 h after spawning, of which 89.6% were floating, with a viability of 96.2% (transparent eggs with a live embryo).…”

“…Fertilized eggs were obtained from the natural spawning of captive broodstock (five females with 0.91 ± 0.2 kg body weight [BW] and 14 males with 1.2 ± 0.3 kg BW). The fish were held in spawning tanks (3.5 m diameter by 1.8 m deep, 18 m 3 ) with a flow‐through system (8 tank volumes/d), strong aeration and covered by a shade cloth (to block 70% of the sunlight) suspended approximately 2 m above the tanks, at the Research Centre for Food and Development (CIAD), Mazatlan, Mexico (Ibarra‐Castro and Alvarez‐Lajonchère 2011). Eggs were collected in a 200‐L tank containing a 20‐L bin screened with 0.5‐mm mesh placed under the outflow of the spawning tanks.…”

“…All eggs were removed from the collector 12–14 h after spawning, at the embryo segmentation stage. The number of eggs floating and sinking were estimated volumetrically with a 500‐mL graduated cylinder, based on the equation E = −18.648 D + 16645; P = 0.05, R 2 = 0.9013, where E is the total number of eggs in 1 mL and D is the mean egg diameter of 50 eggs (Ibarra‐Castro and Alvarez‐Lajonchère 2011). Egg viability was recorded as the percentage of floating eggs with live embryos at that stage, from a sample of floating eggs >120.…”

“…In 2005, a captive broodstock population was established at the CIAD Mazatlan facility, and the first larvae obtained through hormone induction (Ibarra‐Castro and Alvarez‐Lajonchère 2009) enabled the conduction of small‐scale experiments to improve larviculture techniques (Abdo‐de la Parra et al 2010). Afterward, natural spawning of high‐quality eggs from the captive broodstock (Ibarra‐Castro and Alvarez‐Lajonchère 2011) enabled scaling‐up using experimental larval rearing technology (Abdo‐de la Parra et al 2010) to a new pilot‐scale plant (Alvarez‐Lajonchère et al 2007).…”

Partial Characterization of Digestive Proteases in the Common Snook Centropomus undecimalis

“…For several years many studies have been conducted to characterize digestive proteases such as in common dentex (Dentex dentex), blue discus (Symphysodon aequifasciata), burbot (Lota lota) and common carp (Cyprinus carpio) (Alarcón, Díaz, Moyano, & Abellan, 1998;Chong, Natalia, & Hashim, 2002a;Izvekova, Solovyev, Kashinskaya, & Izvekov, 2013;Farhoudi, Abedian, Nazari, & Makhdoomi, 2013). In Mexico, the culture of marine fish is based on a few species such as spotted rose snapper (Lutjanus guttatus) (Ibarra-Castro, & Alvarez-Lajonchère, 2011), totoaba (Totoaba macdonaldi) (Galaviz, et al 2015) and red drum (Sciaenops ocellatus) (Gatlin III, 2002). In the State of Tabasco one of the most important commercial species is the common snook (Centropomus undecimalis), which is considered a euryhaline species with many adequate biological characteristics for its culture (Alvarez-Lajonchère, & Taylor, 2003); nevertheless, digestive physiology related to the changes of the digestive enzyme during initial ontogeny has been briefly studied (Jiménez-Martínez et al 2012).…”