Temperature modifies activity, inter-individual relationships and group structure in a fish

Area of Science:

• Ethology
• Aquatic Ecology
• Fish Biology

Background:

• Abiotic factors are known to influence fish social behavior.
• Limited research has specifically investigated the impact of temperature on fish behavior.
• Understanding these effects is crucial for predicting population dynamics and survival rates.

Purpose of the Study:

• To characterize the effects of different temperatures on brown trout (Salmo trutta) fry behavior.
• To investigate how temperature influences group social structure, inter-individual relationships, and activity levels.
• To assess the implications of temperature-induced behavioral changes on group cohesion and survival.

Main Methods:

• Brown trout fry were reared across five distinct temperatures: 4°C, 6°C, 8°C, 10°C, and 12°C.
• Behavioral parameters analyzed included inter-individual distances (social structure), physical contacts (relationships), and swimming activity.
• Observations were conducted at the emergence stage, a critical transition period for social behavior.

Main Results:

• Inter-individual distances, particularly nearest neighbor distance, increased with rising temperatures.
• The frequency of physical contacts between fry increased at both low (4°C) and high (12°C) temperatures.
• Swimming activity decreased significantly at the extreme temperatures (4°C and 12°C) compared to intermediate temperatures (8°C).

Conclusions:

• Temperature is a significant abiotic factor that modifies brown trout fry social behavior, including activity and inter-individual relationships.
• Altered social behavior and reduced activity at extreme temperatures can impact group cohesion prior to emergence.
• These temperature-driven behavioral changes may influence the survival and dispersal patterns of young brown trout.