Can the Baikal Amphipod Gmelinoides fasciatus (Stebbing, 1899) Have Different Responses to Light Pollution with Different Color Temperatures?

Light pollution can affect various groups of aquatic organisms. This effect will vary depending on the color temperature of the artificial lighting. However, at the moment, the issue of adaptation of organisms to light pollution and the influence of different color temperatures on them has not been well-studied. In this study, we decided to conduct a series of experiments with individuals of the amphipod Gmelinoides fasciatus from two populations and find out how individuals adapted to light pollution. The first group of individuals is from the population in Lake Baikal (Bolshie Koty Bay), and the second group is from the population in the Angara River (within the city of Irkutsk). The second population is significantly affected by light pollution. Since the middle of the last century, there has been an artificial barrier between these populations in the form of a hydroelectric power station. The experiments showed that G. fasciatus individuals developed different behavioral strategies in relation to artificial lighting with different color temperatures. In warm light, individuals tend to move to a shaded area, while in cold light, individuals may be attracted to artificial lighting, but only in small groups. These identified patterns may likely find practical use.