Sensitivity of crabs Callinectes sapidus and C. similis and the gastropod Stramonita haemastoma to hypoxia and anoxia

Abstract

Tolerances of juvenile blue crab, lesser blue crab and adult southern oyster drill to long-term (28 d) hypoxia and short-term (10 d) changes from normoxia to hypoxia and back to normoxia were monitored at 24°C and 30 ‰S. C. sapidus was very sensitive to hypoxia with a 28 d LC50 of 106 Torr O2. All C. sapidus in 25 and 0 Torr O2 died within 6 d of exposure. C. similis exhibited lesser sensitivity to hypoxia with a 28 d LC50 of 43 Torr O2 . All crabs exposed to anoxic water died within 3 d of exposure. S. haemastoma exhibited a 28 d LC50 of 11.5 Torr O2. Under anoxia, initial death occurred in S. haemastoma after Day 11 and complete mortality occurred by Day 22. No significant difference occurred in the feeding rates of blue crabs exposed to normoxia, 119 and 73 Torr O2. Feeding rates in the lesser blue crab exposed to 50 and 25 Torr O2 were significantly lower than in crabs exposed to 119 Torr O2 and normoxia. Growth and molting rates in both species of crabs were significantly higher in the normoxic exposure. -from Authors