Scope for activity in the crayfish Pacifastacus leniusculus

Area of Science:

• Crustacean physiology
• Environmental toxicology
• Aquatic animal metabolism

Background:

• Understanding the metabolic scope of aquatic invertebrates is crucial for predicting their response to environmental changes.
• Pacifastacus leniusculus, a widely distributed decapod crustacean, serves as a model organism for studying physiological adaptations.

Purpose of the Study:

• To determine the thermal tolerance and metabolic scope for activity in Pacifastacus leniusculus.
• To compare the oxygen consumption rates of crayfish with those of various fish species across a range of temperatures.

Main Methods:

• Measurement of standard and active oxygen consumption rates (VO2) at different temperatures (5-30°C).
• Determination of the incipient lethal temperature.
• Calculation of the scope for activity (Active VO2 - Standard VO2).

Main Results:

• The incipient lethal temperature for Pacifastacus leniusculus was 33°C.
• Standard oxygen consumption increased with temperature (Q10 = 2.09).
• Active oxygen consumption and scope for activity peaked at 20°C, with values comparable to moderately active fish species.

Conclusions:

• Pacifastacus leniusculus possesses a well-developed oxygen uptake ability, with a broad thermal tolerance range.
• The metabolic scope of crayfish at optimal temperatures is significant when compared to various fish species.
• These findings highlight the physiological capacity of crayfish to thrive in fluctuating aquatic environments.