Center for Marine Biodiversity and Conservation

There are significant questions about how the physiology and behavior of marine fishes will respond to elevated carbon dioxide concentrations in future ocean conditions, an issue referred to as ocean acidification. Marine fish are the most vulnerable to changes in ocean chemistry at the egg and larval stage because of their thinner skin and heightened exposure to environmental conditions. This study investigates the impacts of elevated carbon dioxide for the swimming behavior of larval white seabass, Atractoscion nobilis. White seabass larvae were reared to 7 days post fertilization under variable carbon dioxide concentrations with the control infused with 380ppm CO2 (close to current atmospheric conditions) and the treatment with 2500ppm CO2. The larvae were filmed in shooting session on days 4-7, and these films were analyzed using imagej particle tracker, an image analysis tool to attain information form the trajectories of each larval movement. Three categories were used to determine swimming conditions; distance traveled along each trajectory, mean swim speeds, and maximum swim speeds. Overall, the results from t-tests showed that there was not a signification difference between the control and treatment for all three categories. The elevated swimming activity of the treatment larvae compared to the control throughout the experiment was a surprising result. There was no observational evidence that the larvae were disoriented under the elevated carbon dioxide as compared to the control and there was no impact for the survival rate to day 7. These results indicate that marine fish larvae may express resilience to changes in swimming behavior from ocean acidification.