Ovulation and initial rearing of Steindachneridion parahybae (Siluriformes: Pimelodidae) larvae from different accumulated thermal units

Abstract

Steindachneridion parahybae is an endemic catfish to the Paraiba do Sul river basin classified as critically endangered. Little is known about the reproductive management of this species in captivity, adopting for this practice empirical measures. The objectives were to:(1) determine suitable Accumulated Thermal Units (ATUs) at the moment of ovulation in January 2011 and 2012; (2) follow initial larvae rearing in 180, 240 and 300 degreehours. Nine selected females were divided into three experimental groups of three specimens each (replications), distributed at pre-established times: 140, 160, 180, 200, 220, 240, 260, 280 and 300 degree-hours. The females were induced with two doses of 0.5 and 5.0 mg kg -1 of dry carp pituitary, respectively, at an interval of 12 h. The extruded oocytes were kept at average water temperature of 22.35 ± 0.53°C (2011) and 21.88 ± 0.15°C (2012). Fertilization and hatching rates were: 84.22 and 71.33 % at 174.2 ATUs in 2011, and 55.58 % and 36.13 % at 251.0 ATUs in 2012. In January 2012, 900 larvae were distributed in three replications (triplicate) consisting of 100 larvae each and were fed: 120 (second day), 300 (thirdfourth day), 600 (fifth-eighth day), and 1,200 Artemia salina nauplii per larva (ninth-15th day), six times a day. The larvae exhibited mean weight of 523.67 ± 54.42, 496.67 ± 61.98 and 475.00 ± 22.83 mg, length of 17.75 ± 0.57, 17.58 ± 0.51 and 17.45 ± 0.25 cm and survival of 63.95 ± 24.50, 71.71 ± 6.61 and 79.65 ± 0.82 %, when hatched in 180, 240 and 300 ATUs, respectively. The larvae body parameters did not show significant differences at these degree-hours.

Inseminating dose and water volume applied to the artificial fertilization of Steindachneridion parahybae (Steindachner, 1877) (Siluriformes: Pimelodidae): Brazilian endangered fish

“…The oocytes were collected after a period of 320 degree-hours (14h after second hormonal induction and water at 22.9°C), registered from the last hormonal injection onward Okawara et al, 2015). Sample was performed by stripping, which consists of gentle abdominal massage in cephalocaudal direction.…”

Reproductive physiology of Rhamdia quelen is improved by dietary inclusion of probiotics

“…Approximately 12 h after fertilization, thee samples of 100 eggs were collected from each experimental unit in triplicate, in order to estimate the Fertilization Rate ( FR = number of viable eggs x 100/ total number of eggs ), considering only the oocytes that presented translucent appearance (Okawara et al., 2015). Relative fecundity ( RF = number of eggs liberated x total weight of the females ) was calculated according to Godinho (2007).…”

Biodiversidade e conservação da ictiofauna ameaçada de extinção da bacia do rio Paraíba do Sul

“…Nós temos avançado no entendimento dos aspectos fundamentais da biologia reprodutiva e do desenvolvimento de S. parahybae em cativeiro. Estudos de Caneppele et al (2009) e Honji et al (2013, estabeleceram o protocolo de indução artificial à reprodução de S. parahybae em cativeiro (respectivamente, de reprodutores selvagens e de origem de cativeiro (F1)); desenvolvimento embrionário e larval (Honji et al, 2012a;Lopes et al, 2015), e a qualidade dos gametas de S. parahybae tem sido descrito também (Honji, 2011;Sanches et al, 2013Sanches et al, , 2014Sanches et al, , 2015Caneppele et al, 2015;Okawara et al, 2015). A reprodução dessa espécie em cativeiro ocorre entre novembro e março, apresentando desenvolvimento oocitá-rio sincrônico, no entanto, durante o período reprodutivo apresenta uma desova em diferentes grupos, ou seja, entre os meses de novembro e março, as fêmeas de S. parahybae podem desovar várias vezes durante o período reprodutivo (Honji, 2011).…”