Effects of Environmental Factors on Egg Development and Hatching of Pacific Halibut Hippoglossus stenolepis

Abstract

Eggs of Pacific halibut were incubated under various environmental conditions. Optimum hatching occurred over a temperature range from 6 C to 8 C, whereas temperatures of 3, 10, and 11 C were lethal. Development time from fertilization to 50% hatching varied from 250 h (9 C) to 320 h (6.5 C). Salinity effects on hatching were not as critical as temperature, as long as eggs were floating during the incubation period. Light intensity between 5 and 15 lux did not affect hatching success, but high light intensity (15 lux) and red and blue light (5 lux) produced high levels of larval abnormality. Simulated transport of unfertilized eggs indicated that the eggs can be safely moved and that fertilization rate is acceptable during the first 12 h after collection.

Culture of Atlantic halibut (Hippoglossus hippoglossus) and Pacific halibut (Hippoglossus stenolepis)

“…Optimum hatching of Pacific halibut eggs occurs over a temperature range from 6 to 8°C (Liu et al, 1993b). Incubation temperatures of 3, 10, and 11°C were lethal.…”

“…Although researchers in Norway routinely transported Atlantic halibut eggs fertilized at sea to their laboratories, it may be more appropriate to transport the gametes separately and to mix them only after they arrive at the hatchery. Liu et al (1993b) reported that 12 h of simulated transportation had no apparent adverse effect on egg mortality or fertilization rate in Pacific halibut. After 28 h of simulated transportation, egg mortality increased dramatically and fertilization rate declined.…”

“…-29 to 33.5 (Uu et al, 1993c) Not known with assurance; full-strength seawater may be appropriate Temperature CO 6 to 8 = Pacific (Liu et al. 1993b) 3 to 6 = Atlantic <9.5 during early stages = Pacific (Liu, 1991) <6 may be optimal -Atlantic (Pittman, 1989(Pittman, , 1990Bolla and Holmefjord, 1988) Up to 12 once fish are established on feed Light <15 lux white, or darkness (Liu et al, 1993b) Low light or darkness may reduce deformities; light should be provided when time of first feeding approaches (Bolla and Holmefjord,…”

“…At lower salinities (21 and 24 ppt), eggs settled to the bottom of incubators where they were exposed to debris and died. Salinities <27 ppt may be suitable if the eggs can be maintained within the water column during incubation (Liu et al, 1993b).…”

Influência da salinidade na incubação de ovos do robalo-peva (Centropomus parallelus Poey, 1860)

“…Tucker (1987) observou que os ovos do robalo-flecha Centropomus undecimalis afundavam com salinidade abaixo de 28. Liu et al (1994) observaram que os ovos do linguado do Pacífico (Hipoglossus stenolepsis) afundavam em salinidade abaixo de 30. Smith et al (1999) determinaram que os ovos do linguado Paralichthys lethostigma flutuavam somente a partir da salinidade de 31, e que a taxa de eclosão foi influenciada pela salinidade.…”