Desove espontáneo, ontogenia y crecimiento en cautiverio de Cynoscion squamipinnis (Perciformes: Sciaenidae) / Spontaneous spawning, ontogeny and growth in captivity of Cynoscion squamipinnis (Perciformes: Sciaenidae)

ResumenLas corvinas son especies de interés comercial que han sido sobreexplotadas en el Golfo de Nicoya, Costa Rica. El objetivo de este estudio fue describir por primera vez, el desove espontáneo y la ontogenia de las larvas de la corvina aguada Cynoscion squamipinnis en cautiverio, con el fin de realizar repoblamiento y proyectos de maricultura. Reproductores silvestres (n= 6, 1-2 Kg), fueron capturados y mantenidos en la Estación de Biología Marina Juan Bertoglia Richards (Puntarenas, Costa Rica) por un periodo de dos años (octubre 2006-diciembre 2008). Durante este periodo, el estado de madurez de las hembras (n= 3) fue registrado mediante muestras de cánula y los machos (n= 3) mediante masaje abdominal. Todos los reproductores fueron colocados juntos en un tanque de 18 t, con aireación, a una salinidad entre 33-35 ups y expuestos a una temperatura constante (29 ± 1 °C). De enero a marzo 2009 ocurrió un periodo de desove espontáneo, obteniéndose 162 000 huevos en tres desoves. El porcentaje de fertilización fue de 50-60 %, y la supervivencia después de la eclosión fue entre 60-85 %. El diámetro de los huevos fue de 0.852 mm (Desviación Estándar= 0.039), con una gota de aceite de 0.269 mm (DE= 0.016). En el desarrollo embrionario, la primera división mitótica ocurrió una hora después del desove (hdd), la segunda división 1:30 hdd, la tercera división 2 hdd, la cuarta división a las 2:30 hdd, y la quinta 3:00 hdd. La mórula fue observada a las 3:30 hdd, la blástula a las 4:30 hdd, la gástrula a las 8:30 hdd, la forma C a las 10:00 hdd, y la forma S ocurrió de las 10-19 hdd. La eclosión ocurrió 19 hdd. La larva midió 2.234 mm (DE= 0.122) de longitud total (LT), y 2.179 mm (DE= 0.119) de longitud notocordial (LN). La preflexión inició 49 hdd, la flexión 11 días después del desove (ddd) (3.767 mm LT, DE= 0.209), y la postflexión a los 14 ddd (4.015 mm LT, DE= 0.302). A los 45 ddd, los juveniles pesaron 3.68 g (DE= 1.09). El tiempo de eclosión de las larvas de la corvina aguada fue menor al de otras especies de corvina. Los tiempos de formación en las etapas embrionarias difirieron poco con respecto a los tiempos observados para otras especies de corvinas. Las diferencias observadas con respecto a otras especies, probablemente responden a las características genéticas propias de cada especie y a la temperatura de incubación de los huevos. La obtención de desoves espontáneos sin aplicaciones hormonales a los reproductores, y la producción de juveniles en cautiverio demostraron que la corvina aguada puede ser considerada en programas de repoblamiento y proyectos de maricultura.

Abstract:The croakers or drums are commercial species, which have been overfished in the Nicoya Gulf, Costa Rica. This study aimed to describe, for the first time, the reproduction and the ontogeny of weakfish, Cynoscion squamipinnis in captivity, in order to perform restocking and mariculture projects. Wild fish (n= 6, 1-2 Kg) were captured and maintained in the Estación de Biología Marina Juan Bertoglia Richards (Puntarenas, Costa Rica) for a two years period (October 2006- December 2008). During this period, maturation stage was monitored periodically by cannula samples in the females (n= 3) and gentle massage in males (n= 3). All fish were stocked in an 18 t tank, with aeration, 33-35 ups of salinity, and a constant temperature (29 ± 1 °C). The spawning period occurred from January to March 2009, producing 162 000 eggs in three spontaneous spawns. The fertilization percentage was 50-60%, and survival after hatching was 60-85%. The egg diameter was 0.852 mm (Standard deviation (SD)= 0.039), and oil drop of 0.269 mm (SD= 0.016). In the embryonary development, the first mitotic division (MD) was observed one hour after spawning (has), the second MD was 1:30 has, the third MD was 2:00 has, the fourth MD was 2:30 has, and fifth MD at 3:00 has. Morule was observed 3:30 has, the blastule 4:30 has, the gastrule 8:30 has, C shape at 10:00 has, and C shape at 12:00 has. After 19 has hatching larvae occurred. The total length (TL) of the larvae was 2.234 mm (SD= 0.122), and the nothochordial length (NL) was 2.179 mm (SD= 0.119). Preflexion stage was observed 49 has, flexion stage was 11 days after spawn (das) (3.767 mm LT (SD= 0.209)), and postflexion stage was 14 das (4.015 mm LT (SD= 0.302)). After 45 das, the juvenile weights 3.68 g (SD= 1.09). Hatch time of the weakfish larvae was minor than of others croaker species. The stages times of embrionary development were a little different from others croaker species, and probably respond to genetic characteristics of each species and the eggs incubation temperature. The spontaneously spawning without broodstock hormonal applications, and the juveniles production in captivity showed that weakfish is a potential species for restocking programs and mariculture projects. Rev. Biol. Trop. 64 (3): 991-1005. Epub 2016 September 01.

[Spontaneous spawning, ontogeny and growth in captivity of Cynoscion squamipinnis (Perciformes: Sciaenidae)]. / Desove espontáneo, ontogenia y crecimiento en cautiverio de Cynoscion squamipinnis (Perciformes: Sciaenidae).

The croakers or drums are commercial species, which have been overfished in the Nicoya Gulf, Costa Rica. This study aimed to describe, for the first time, the reproduction and the ontogeny of weakfish, Cynoscion squamipinnis in captivity, in order to perform restocking and mariculture proyects. Wild fish (n= 6, 1-2 Kg) were captured and maintained in the Estación de Biología Marina Juan Bertoglia Richards (Puntarenas, Costa Rica) for a two years period (October 2006- December 2008). During this period, maturation stage was monitored periodically by cannula samples in the females (n= 3) and gentle massage in males (n= 3). All fish were stocked in an 18 t tank, with aeration, 33-35 ups of salinity, and a constant temperature (29 ± 1 °C). The spawning period occurred from January to March 2009, producing 162 000 eggs in three spontaneous spawns. The fertilization percentage was 50-60%, and survival after hatching was 60-85%. The egg diameter was 0.852 mm (Standard deviation (SD)= 0.039), and oil drop of 0.269 mm (SD= 0.016). In the embryonary development, the first mitotic division (MD) was observed one hour after spawning (has), the second MD was 1:30 has, the third MD was 2:00 has, the fourth MD was 2:30 has, and fifth MD at 3:00 has. Morule was observed 3:30 has, the blastule 4:30 has, the gastrule 8:30 has, C shape at 10:00 has, and C shape at 12:00 has. After 19 has hatching larvae occurred. The total length (TL) of the larvae was 2.234 mm (SD= 0.122), and the nothochordial length (NL) was 2.179 mm (SD= 0.119). Preflexion stage was observed 49 has, flexion stage was 11 days after spawn (das) (3.767 mm LT (SD= 0.209)), and postflexion stage was 14 das (4.015 mm LT (SD= 0.302)). After 45 das, the juvenile weights 3.68 g (SD= 1.09). Hatch time of the weakfish larvae was minor than of others croaker species. The stages times of embrionary development were a little different from others croaker species, and probably respond to genetic characteristics of each species and the eggs incubation temperature. The spontaneously spawning without broodstock hormonal applications, and the juveniles production in captivity showed that weakfish is a potential species for restocking programs and mariculture projects.