Induced Spawning, Artificial Fertilization, and Egg Incubation Techniques for Green Sturgeon

Abstract

Establishment of hatchery breeding techniques for the threatened green sturgeon Acipenser medirostris is important for research and conservation hatcheries. Injections of either gonadotropin-releasing hormone analog (GnRHa) or GnRHa plus domperidone were used to induce ovulation in 13 female Klamath River green sturgeon and to induce spermiation in 19 males. Ovulated eggs were either rinsed in water or not rinsed before fertilization, and the eggs were fertilized with different milt dilutions and for different lengths of time. After fertilization, eggs either were allowed to adhere to the bottom of glass dishes or were silted for 1 h and then incubated in McDonald or upwelling jars. All broodfish ovulated or spermiated in all hormonal treatments, and the best treatment was GnRHa injected alone in a single dose of 10 lg/kg for males or in a 1lg/kg priming dose and a 19-lg/kg resolving dose for females. Females were held at 12-138C, and ovulation was observed 14 6 3 h (mean 6 SD) after the second injection. Domperidone was not required for successful ovulation and appeared to reduce the adhesion of ovulated eggs. From 49,000 to 115,000 eggs were collected from each female, and from 30 to 300 mL of milt were collected from each male. Sperm cell concentrations in milt ranged from 2.9 3 10 8 to 5.4 3 10 9 sperm/mL, and the sperm exhibited 90-100% motility for up to 5 min. In all experiments, egg rinsing improved fertilization success by 5-12%. Embryo survival to neurulation in the McDonald jars was lower (5-32%) than that in the upwelling incubators (60-82%). Green sturgeon eggs were sensitive to the high-impact rolling action at the bottom of the McDonald jars, probably due to the large egg diameter (mean 6 SD ¼ 4.33 6 0.14 mm) and thinner chorion (42 6 4 lm) relative to eggs of white sturgeon A. transmontanus (diameter ¼ 3.79 6 0.03 mm; chorion thickness ¼ 115 6 6 lm).

Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon

“…Green sturgeon larvae were F2 offspring from captive F1 broodstock originating from wild-caught Klamath River Northern DPS sturgeon (Van Eenennaam et al, 2008, 2012. The captive F1 broodstock were maintained at an annual mean temperature of 18.5 ± 1.3°C (mean ± SD) and artificially spawned at 15 ± 0.5°C at the Center for Aquatic Biology and Aquaculture (CABA) at the University of California, Davis, CA, USA.…”

Effect of Nutritional Status on the Osmoregulation of Green Sturgeon (Acipenser medirostris)

“…Juvenile green sturgeon were obtained from captive F 1 broodstock that had been reared from wild-caught Klamath River sturgeon spawned in -2000(Van Eenennaam et al 2008) and held in the Center for Aquatic Biology and Aquaculture at the University of California, Davis. The female (year 1999 class) was tank spawned with two males from the year 2000 class (Van Eenennaam et al 2012).…”

Effects of nutritional deprivation on juvenile green sturgeon growth and thermal tolerance

“…Broodstock were matured at 18.5 (±0.5)°C, then artificially-spawned at 15 (±0.5)°C under aquaculture conditions at the Center for Aquatic Biology and Aquaculture (CABA), University of California Davis (UCD) (Van Eenennaam et al 2008. Sturgeon were held in tanks or experimental holding containers supplied with aerated degassed well water through all rearing from egg incubation through experimental treatments and tests.…”