Gilthead seabream, Sparus aurata (Linneaus, 1785) is one of the significant commercial fish species in the Mediterranean Sea. It shows a different annual seasonal distribution characterized by migrations to coastal and estuarine areas. Its number has increased in recent years, especially in the areas of shellfish farming where it has also causing significant damage. The study of the daily and seasonal frequency of gilthead seabream, Sparus aurata (Linnaeus, 1758), in the estuary of the Krka River, in the bay of Martinska near Šibenik, was conducted in 2019 using an underwater video camera with cable power. The seasonality of the appearance of individuals was analyzed in the context of the ethology of basic physiological processes, primarily spawning and feeding. The highest numbers were found in January, and the lowest in November. The highest daily activity was in the afternoon. Unlike research with classical fishing techniques, the underwater camera assessment method is non-invasive and allows constant monitoring. The use of an underwater camera has proven to be a valuable tool for ichthyological research. In order to collect detailed data on the seasonal changes in abundance of species, it would be desirable to conduct continuous monitoring and expand the research by correlating abiotic ecological parameters (salinity, temperature, etc.).