Effects of emersion temperature on the oxygen consumption rates of male tanner crabs, Chionoecetes bairdi

Delivery of live crustaceans to markets has the potential to increase profits for Alaskan fishermen, but the practice has been limited in part by mortality occurring during shipment to distant markets. Protocols that select crabs more likely to survive shipment would likely further develop this niche market and evaluating the physiological stress response in crustaceans provides a logical entry point to explore this area. This study measures oxygen consumption rates (MO₂; mgO₂ g^-1 hr ^-1) of male Tanner crabs, Chionoecetes bairdi, following 15, 30 or 45 min of emersion at 8°C or -15°C followed 12 h later by a uniform handling stressor (emersion at -15°C for 10 min). MO₂ increased immediately following 15, 30 and 45 min emersion at 8°C (on average 1.5 times pre-treatment levels). All crabs survived emersion at 8°C and MO ₂ returned to pre-treatment levels within 12 hours. These animals also responded similarly to a uniform second stress test by increasing MO ₂. Crabs previously exposed to air at - 15°C for 15 min had an increased MO₂ following a standardized handling stress in a pattern similar to the 8°C groups. However, MO₂ in crabs exposed to air at - 15°C for 30 min did not respond to a uniform secondary stress treatment with an increase in MO₂. Thus, a robust increase in MO₂ to a uniform stress treatment indicates animals with a less severe stress history and likely an indicator of overall vigor.