The influence of light colour on the behaviour of Atlantic cod in an experimental setting

Fishing technologies often exploit the visual sensitivity of target species to alter their behaviours. Atlantic cod ( Gadus morhua Linnaeus, 1758) are an economically important species, commonly targeted by fisheries in the North Atlantic, yet the behaviour of adult Atlantic cod in reaction to the simultaneous presentation of various light stimuli has not been assessed in an isolated setting to determine if there is a preference for certain light qualities. To assess the influence that artificial light may have on the behaviour of Atlantic cod, we investigated the movement of wild-caught cod in a laboratory setting with green, blue, and white light with a blank control presented in paired choice tests. We predicted that green light would have the greatest influence on cod behaviour and that they would preferentially spend more time in proximity to that light condition. The findings show that cod behaved consistently across trials and across experimental sessions, and that the right side of the arena was preferred regardless of the colours of light presented. These findings indicate that cod do not prefer to spend more time in proximity to certain colours of light in an artificial environment, which has direct implications for animal husbandry, fisheries research, and behavioural ecology.