Effects of Limited Dissolved Oxygen Supply on the Growth and Energy Allocation of Juvenile Chinese Shrimp, Fenneropenaeus chinensis

Information about the effect of hypoxia exposure on energy allocation is helpful for better understanding how aquatic animals tolerate and adapt to a hypoxic environment. The growth, molting, and energy allocation were investigated in juvenile Fenneropenaeus chinensis exposed to five different dissolved oxygen (DO) seawaters (2.09 +/- 0.15, 3.10 +/- 0.29, 4.13 +/- 0.25, 4.73 +/- 0.12, and 5.48 +/- 0.09 mg/L DO) for 30 d. When DO was below 4.13 mg/L, the growth of shrimp was depressed. Feed ingestion and feed conversion efficiency decreased with the decrease of DO. Less feed ingestion was caused by lower daily metabolic energy. Higher proportion of ingested energy lost in metabolism, exuviations, and nitrogen excretion caused lower feed conversion efficiency. More energy lost in exuviations, lower survival rate, soft carapaces of dead shrimp, and cannibalism were found in oxygen deficient groups and it implicated that hypoxia could delay the shrimp recovering from molting and cause cannibalism and higher mortality. The results indicated that hypoxia was an important factor affecting the amount and fitness of shrimp stock because it could cause a high rate of mortality and growth depression.