Effects of hypoxia on feed intake and gonad growth in the green sea urchin, Strongylocentrotus droebachiensis

The effects of oxygen content 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 51.0 (12.2) g were reared at oxygen levels of 4.0, 6.0 (hypoxia) and 9.5 mg l− 1 (normoxia), for 54 days at 8.0 °C and 33‰.Gonad growth and total food consumption were significantly higher in the control group (normoxia) compared with the hypoxic groups at the end of the experiment. Weekly feed intake and total feed consumption were significantly reduced in the two hypoxic groups. The reduction in gonad growth was attributed to a decrease in feed intake and impaired food conversion efficiency. Overall, our findings suggest that adult green sea urchins show low tolerance to hypoxia, and are unable to maintain high gonad growth facing such conditions.