Physiological responses of postlarval and juvenile blue crabs Callinectes sapidus to hypoxia and anoxia

• Published in: Marine ecology. Progress series (Halstenbek) Vol. 194; pp. 179 - 191
• Main Authors: Tankersley, Richard A., Wieber, Maria G.
• Format: Journal Article
• Language: English
• Published: Oldendorf Inter-Research 17-03-2000
• Subjects: Anaerobic conditions; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Anoxia; Aquatic habitats; Autoecology; Biological and medical sciences; Callinectes sapidus; Crabs; Fundamental and applied biological sciences. Psychology; Hypoxia; Marine; Metamorphosis; Oxygen; Oxygen consumption; Oxygen partial pressure; Protozoa. Invertebrata; Young animals; North Carolina; United States; North America; America; ANW, USA, North Carolina, Newport Estuary; Brackish water environment; Oxygen; Anoxia; Brachyura; Estuaries; Tolerance; Environmental factor; Oxygen consumption; Survival; Young animal; Crustacea; Megalop instar; Callinectes sapidus; Arthropoda; Hypoxia; Decapoda; Invertebrata; Metamorphosis
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps194179

The influence of hypoxia and anoxia on the oxygen consumption, survivorship and rate of metamorphosis of field-caught postlarvae (megalopae) and first-instar juveniles of the blue crab Callinectes sapidus was observed under laboratory conditions. Rates of oxygen uptake by megalopae were independent of ${\mathrm{P}}_{{\mathrm{O}}_{2}}$ at oxygen tensions above 8.88 kPa. However, Pc for juvenile crabs was significantly higher than for megalopae (89.6 vs 43.2% saturation). Tolerance of blue crab megalopae of hypoxic conditions below 20% saturation (∼4.12 kPa) was greater than for newly metamorphosed juveniles. Juvenile crabs also succumbed to the effects of anoxia more rapidly than megalopae, but neither group survived exposure of >5 h. Megalopae and crabs that became immobile in anoxic water quickly recovered when returned to normoxic conditions. Metamorphosis of megalopae to the first-juvenile stage was delayed when they were exposed to ${\mathrm{P}}_{{\mathrm{O}}_{2}}$ values of 8.21 and 12.32 kPa (40 and 60% saturation). Similarly, time to metamorphosis increased significantly when megalopae were temporarily exposed to hypoxic conditions (${\mathrm{P}}_{{\mathrm{O}}_{2}}=4.12 \ \mathrm{k}\mathrm{P}\mathrm{a}$) for 4 h each day. However, there was no significant difference between the time to metamorphosis for megalopae exposed to hypoxic conditions for 2 h each day and those maintained in oxygen-saturated water. These results suggest that the presence of hypoxic and anoxic water in deep water layers and shallow near-shore habitats of estuaries during the summer months may influence the onshore migration, settlement and survival of blue crab megalopae and newly metamorphosed juvenile crabs.