title: Temperature-mediated survival, development and hatching variation of Pacific cod Gadus macrocephalus eggs.
abstract: Laboratory-validated data on the survival, development and hatching responses of fertilized Pacific cod Gadus macrocephalus eggs from the northern Japan stock were determined through an incubation experiment. The optimum temperature for survival until hatching ranged from 4 to 8°C. No significant difference in development rates was found between the populations from Mutsu Bay, Japan, and western Canadian coastal waters even though the samples may belong to different G. macrocephalus stocks. Gadus macrocephalus larvae hatched asynchronously from egg batches despite incubation under the same environment during their development. Both incubation temperature and temperature-mediated hatch rank affect size and yolk reserve. These data suggest that variations in water temperatures within an ecological range markedly influence the development rates, survival and hatching of the eggs, as well as the stage at hatch larvae of G. macrocephalus. Asynchronous hatching and the production of offspring with variable sizes and yolk reserves are considered evolutionary bet-hedging strategies that enable the species to maximize their likelihood of survival in an environment with variable temperatures.
authors.affiliation: The Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, CAFS, Qingdao 266071, China.
authors.forename: X
authors.initials: X
authors.lastname: Bian
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Sakrai
authors.forename: X
authors.initials: X
authors.lastname: Jin
authors.forename: T
authors.initials: T
authors.lastname: Gao
authors.forename: R
authors.initials: R
authors.lastname: Wan
authors.forename: J
authors.initials: J
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D002170:Canada; D004530:Egg Yolk; D048388:Gadiformes / Q000502:physiology*; D007564:Japan; D007814:Larva; D008954:Models, Biological; D012044:Regression Analysis; D013696:Temperature; D013997:Time Factors; D015053:Zygote / Q000254:growth & development*
keywords: Mutsu Bay; asynchronous hatching; daily mortality; hatch rank; stage duration; temperature-dependent