Effects of carbon dioxide exposure on feed intake and gonad growth in green sea urchin, Strongylocentrotus droebachiensis

The effects of carbon dioxide (CO2(aq)) on gonad growth and feed intake in green sea urchin, Strongylocentrotus droebachiensis, were examined. Adult sea urchins with a mean (S.D.) live weight of 50.0 (11.2) g were exposed to two levels of carbon dioxide (CO2(aq)), (1.1 (control) and 18.1 mg l− 1), for 56 days at 6.0 °C and 33‰.Gonad growth was significantly reduced in the high CO2 concentration group compared to the control group. In the high carbon dioxide treatment, gonad growth was 67% less than the control treatment. Weekly feed intake and total feed consumption were significantly reduced in the high concentration group. The reduction in gonad growth was attributed to a decrease in feed intake and impaired feed conversion efficiency. The present study demonstrates that adult green sea urchins show low tolerance to increased carbon dioxide levels, and are unable to maintain high gonad growth facing such conditions.