Ontogenetic Plasticity in Shoaling Behavior in a Forage Fish under Warming.

This article investigates how shoaling behavior and thermal sensitivity change across the ontogeny of zebrafish (Danio rerio), a small freshwater forage fish, under two temperature conditions (28°C and 32°C). The study finds that shoaling performance improves from larval to juvenile to adult stages, characterized by increased cohesion (decreased mean separation distance) and reduced tail beat frequency and head-to-tail amplitude, which enhance locomotor efficiency. Warming affects metabolic rates and swimming kinematics differently across life stages, with juveniles showing unusually high thermal sensitivity in resting metabolic rates, while larvae exhibit increased tail beat frequency at higher temperatures and speeds, indicating lower efficiency. These results highlight complex interactions between temperature, development, and collective behavior, suggesting that early life stages may be more vulnerable to warming, which has implications for the survival and resilience of shoaling fish species under climate change.