Desove espontáneo, ontogenia y crecimiento en cautiverio de Cynoscion squamipinnis (Perciformes: Sciaenidae)

Abstract

Spontaneous spawning, ontogeny and growth in captivity of 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 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.

Desove espontáneo en cautiverio de la primera generación criada en laboratorio de corvina aguada, <i>Cynoscion squamipinnis</i> (Perciformes: Sciaenidae)

“…When the ovarian sample was taken, oocyte diameter was measured ranging between 0.4 and 0.6 mm in one of the marked females (4 females). However, the ovarian samples extracted from the other females did not show oocytes in the advanced stages of vitellogenesis (Boza-Abarca et al 2016a). On February 8, 2011, the first spontaneous spawning occurred, obtaining 28,500 eggs, and the process continued during the following months with a total of 34 reported spawns until October 2011 (Table 1, Fig.…”

“…Tropical species are not exposed to extreme changes of temperature and photoperiod, although it is has been verified that maintaining a constant temperature throughout the process facilitates maturation and spawning, as was the case with C. squamipinnis (Boza-Abarca et al 2016a). In this case, spawning synchronization seemed to be more related to the tides and moon phases, as well as to certain precipitation events that occurred some days before spawning.…”

“…In the case of C. squamipinnis, the two years that the adaptation process took for the samples captured in the Gulf of Nicoya to spawn (Boza-Abarca et al 2016a in press), and the ones reared in the laboratory from egg indicate that the species adapted well to the captivity conditions in the Juan Bertoglia Richards Marine Biology Station.…”

“…Spontaneous spawning of wild weakfish C. squamipinnis was observed after two years in captivity under a constant regime of temperature (29 ± 1°C) (Boza et al 2016a). Juveniles produced from these spawns were maintained under laboratory conditions.…”

“…In Costa Rica, captured weakfish, C. squamipinnis, spawned spontaneously without any hormone treatment (Boza et al 2016a), and juveniles produced were grown out (Boza-Abarca et al 2016b) and maintained in captivity as the first hatchery-produced generation.…”