Behavioral thermoregulation in the American lobster Homarus americanus

Area of Science:

• Marine Biology
• Animal Behavior
• Physiological Ecology

Background:

• Water temperature significantly impacts American lobster (Homarus americanus) behavior, though direct behavioral evidence is limited.
• Understanding thermal preferences is crucial for predicting lobster distribution and responses to environmental changes.

Purpose of the Study:

• To quantitatively assess the behavioral responses of American lobsters to varying water temperatures and thermal gradients.
• To determine if lobsters exhibit behavioral thermoregulation based on acclimation temperature.

Main Methods:

• Three experiments were conducted: thermal avoidance, shelter selection, and free-movement in a thermal gradient.
• Lobsters were acclimated to either summer (15.5°C) or winter (4.3°C) temperatures.
• Behavioral responses, including avoidance temperatures and preferred thermal niches, were recorded.

Main Results:

• Summer-acclimated lobsters avoided water above 23.5°C, while winter-acclimated lobsters did not find similar temperature increases aversive.
• Lobsters selected shelters slightly above ambient temperatures, with winter-acclimated lobsters strongly preferring heated shelters.
• In a thermal gradient, lobsters preferred a niche of 16.5°C, generally selecting water 1.2°C above their acclimation temperature.

Conclusions:

• American lobsters can sense water temperature and actively thermoregulate their behavior.
• Acclimation temperature significantly influences thermal tolerance and preference.
• These findings have implications for understanding lobster habitat use and distribution patterns in response to changing ocean temperatures.