Oceanic acidification - Hatching rates of wild and farmed atlantic cod (Gadus morhua)

Ocean acidification (OA) has been shown to affect larval development in fish but with little change in egg fertilization and hatching success when gametes alone are incubated at higher CO2 level. Little is known of the effects of OA on adult fish reproduction. In the present study we planned to examine the influence of OA on reproduction itself in the adult atlantic cod in both farmed and wild fish. In future OA scenarios it is clear that all life stages will be exposed to higher CO2 levels. It is therefore logical to look at responses of fecundity and gonad development in these stages before examining egg and larval survival from such parents. The wider significance of this project is that the influence of OA at the broodstock level is unknown within fish species and the NOFIMA infrastructure access provides a unique opportunity to study this threat to the cod populations of the future. Through pre-incubation of parents at high and low CO2 levels it has been possible to study trans-generation effects with eggs and sperm from fish with and without pre-exposure to carbon dioxide (OA)