Diurnal vertical movements in black sea bass (Centropristis striata): Endogenous, facultative, or something else?

Abstract Fishes commonly exhibit diel rhythms in movements with consequences to feeding, reproduction, predator evasion, and resting. Such behaviors are conceived as plastic, persisting for phases (days to weeks), and then becoming disrupted, masked, and altered by changed environmental or ecological conditions. In telemetered black sea bass Centropristis striata (family Serranidae), we documented a remarkable 4‐month record of persistent diurnal vertical movements. Within the U.S. Mid‐Atlantic Bight June–October 2019 setting, biotelemetry data of 31 fish were examined through time series analysis and generalized additive modeling. Sun altitude played a dominant role throughout the series, where movements were diurnal. Thermal conditions were uniform until a September hurricane caused a 10°C rise in inhabited waters within the span of six hours, the result of water column mixing. This and other storms caused short‐term disruptions (