Cognitive costs of captivity: hatchery-reared marbled rockfish have impaired spatial cognition

Hatchery-reared fish typically display marked behavioral differences compared to wild conspecifics. For reef-dwelling species, spatial cognition is critical to navigate complex and dynamic habitats. If captive rearing influences these abilities in fish reared for release into nature, then optimization of rearing environments and practices may be necessary. We compared hatchery-reared and wild marbled rockfish ( Sebastiscus marmoratus ) in laboratory spatial cognition tests aimed at investigating differences in navigation strategies, behavioral lateralization, and cognitive flexibility. These tests were complemented by neuroanatomical analyses of brain regions involved in spatial processing. Hatchery-reared fish showed no consistent turning directionality, whereas wild fish had a general population-level lateralization (right-turning bias). In maze tests, wild fish navigated significantly faster and achieved higher success rates than hatchery fish. During reversal learning, wild fish adapted more efficiently, demonstrating better cognitive flexibility. Both hatchery-reared and wild fish predominantly relied on egocentric (turn-based) strategies, with limited use of allocentric (landmark-based) cues. No significant differences were detected in the relative volumes of the telencephalon or cerebellum, or in neuronal density. These findings indicate that captive rearing can impair spatial cognition and behavioral flexibility in fish, which could reduce environmental adaptability and may help explain the poor post-release survival of hatchery-reared reef species.