Is spawning time of marine fish imprinted in the genes? A two-generation experiment on local Atlantic cod (Gadus morhua L.) populations from different geographical regions

Otterå*, H., Agnalt, A-L., Thorsen, A., Kjesbu, O.S., Dahle, G., and Jørstad, K. 2012. Is spawning time of marine fish imprinted in the genes? A two-generation experiment on local Atlantic cod (Gadus morhua L.) populations from different geographical regions. – ICES Journal of Marine Science, 69: 1722–1728. Spawning time (onset of spawning) in Atlantic cod (Gadus morhua L.) was monitored in an experimental setup and combined with modelled spawning time estimates from the wild. The experiment broodstock were collected from several geographical areas and kept in a common environment. Their spawning times in 2004 were compared with the spawning times of their daughters in 2009 and 2010. Daughter spawning time was highly correlated with that of the mother, indicating genetic regulation of spawning time. However, large individual variation in spawning time was observed. The modelling data suggests a north-south gradient in onset of spawning along the Norwegian coast, driven by differences in temperature, i.e. later dates of spawning in the north.