Effects of ocean acidification and paternity on the early life stages of Atlantic cod (Gadus morhua) from the south-east Canadian shelf

• Main Author: Steffen, Gregor T.
• Format: Thesis
• Language: English
• Published: 2012
• Subjects: atlantic cod; Gadus morhua; Ocean acidification
• Online Access: https://oceanrep.geomar.de/id/eprint/19993/; https://oceanrep.geomar.de/id/eprint/19993/1/-%20Effects%20of%20ocean%20acidification%20and%20paternity%20on%20the%20early%20life%20stages%20of%20Atlantic%20cod%20%20from%20the%20south-east%20Canadian%20shelf.pdf

Future climate change mainly accelerated by anthropogenic activities which emitted since the industrial era excess amounts of carbon dioxide (CO2) into the atmosphere, will modify, by CO2 absorption, ocean water chemistry. It has been shown in many studies that marine organisms are affected by this rise in subsurface seawater carbon dioxide concentration. But today’s knowledge about how marine fish species will deal with this possible stressor is not well understood. Their potential acclimatization and adaptive responses are largely unknown. Especially the knowledge that early life stages are more vulnerable than adult fish to adverse environmental conditions forces the need for acidification experiments with a focus on these sensitive stages. A triplicate crossing of gametes from seven males and one female Atlantic cod (Gadus morhua) from aquaculture reared fish of south-east Canadian shelf origin produced embryos of seven half sib families, which then were cultured in seawater under three elevated pCO2 concentrations at 800, 1400, 4000 and 400 μatm as the control, respectively. The pCO2 incubation started with fertilization and ended after the hatchlings were sampled. Survival from fertilization to early cleavage (64-128 cell stage) was negatively affected by pCO2 concentrations, with significant interaction effects with paternity. Elevated pCO2 concentrations had significant adverse effects on hatching success, but in this case neither paternal or interaction effects were significant. Time to 50% hatch and body length at time to 50% hatch could not be evaluated statistically due to high variance in replicates and an insufficient number of hatchlings but based on mean values showed a slight decrease in body length associated with an earlier hatch date in the hypercapnic treatments in relation to the control. However, ocean acidification is only one stressor associated with climate change and may act synergistically with other environmental factors. Thus, the combination with warming, hypoxia, and perhaps ...