Energetically defining the thermal limits of the snow crab

• Main Authors: P. Foyle, Ronald K. O'dor, Robert, W. Elner
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1989
• Subjects: Key words; energetics; respiration; physiology; snow crab; Chionoecetes; Crustacea; Decapoda; Chionoecetes opilio; Snow crab
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.536.1163; http://jeb.biologists.org/content/145/1/371.full.pdf

The snow crab, Chionoecetes opilio, is a cold-water species found naturally at temperatures below 5°C. Its physiology and energetics were examined to understand the metabolic limitations that restrict the snow crab to these temperatures. The species is not confined to cold water because of a limited respiratory system. Routine oxygen demand can be met even at lethal tempera-tures of 18°C (56mgO2kg~1h"1, with a Qi0 of 2-2). Blood lactate levels remain below l'Smmoll"1 and actually decline slightly with temperature. Energy budgets, which were constructed from an examination of oxygen uptake, activity and food consumption in morphometrically mature male animals between 0 and 18 °C, indicate that the snow crab is energetically restricted to cold water. Rising metabolic costs overtake caloric intake around 7°C. This is probably due to digestive metabolism which is temperature-sensitive. Food consumption increases up to 6°C but then falls. Crabs stop feeding above 12°C. Although the growth equation is positive between 1 and 7°C, it becomes slightly negative below 1°C. This observation is unexpected since snow crabs are commonly found between 0 and 1 °C. Slight temperature changes in the natural environment may, therefore, regulate growth and reproduction in this species.