Barren environment damages cognitive abilities in fish: Behavioral and transcriptome mechanisms

Area of Science:

• Marine biology
• Animal behavior
• Neuroscience
• Environmental science

Background:

• Environmental complexity influences animal phenotypes, including behavior and physiology.
• While environmental complexity affects fish behavior, its impact on spatial cognition and underlying mechanisms remains understudied.
• Black rockfish (Sebastes schlegelii) are a typical rockfish species relevant for studying environmental effects.

Purpose of the Study:

• To investigate the effects of environmental complexity on spatial cognition in black rockfish.
• To identify the molecular regulatory mechanisms associated with environmental complexity and fish cognition.
• To compare behavioral performance and physiological status between fish in complex and barren environments.

Main Methods:

• Black rockfish were exposed to contrasting laboratory environments (complex vs. barren) for seven weeks.
• Spatial cognitive abilities (learning and memory) and behavioral patterns were assessed.
• Transcriptome sequencing of the fish telencephalon was performed to identify differentially expressed genes.

Main Results:

• Fish in the complex environment exhibited significantly better spatial learning and memory than those in the barren environment.
• Barren environment fish showed higher aggression and group dispersion, indicating altered social behavior.
• Transcriptomic analysis revealed genes related to stress response, metabolism, and neural plasticity were differentially expressed, potentially explaining cognitive deficits.

Conclusions:

• Environmental complexity plays a crucial role in shaping fish spatial cognition and behavior.
• Barren environments can impair cognitive functions and alter behavioral patterns through molecular mechanisms, including stress and neural plasticity pathways.
• This study provides insights into the behavioral and molecular basis of environmental effects on marine animal cognition.