This study investigated pelagic longline and hook-and-line fisheries in the eastern part of the Adriatic Sea, mainly targeting tuna and swordfish, and observed the impact on vulnerable and sensitive groups of marine organisms caught as bycatch in the eastern Adriatic Sea. The study was conducted from April 2021 to May 2022 and two methods of data collection were used: via questionnaires and directly on the vessel by observer teams. The analysis of the collected data revealed that pelagic longline fisheries have a significant bycatch of endangered shark species, rays and sea turtles, while marine mammals and birds were not recorded as bycatch. Furthermore, a high survival rate of captured sharks, rays and turtles after release or return to the sea was found, which is important for the conservation of these species, especially considering their biology, which includes slow maturation and a low reproduction rate. It was found that sharks and rays are the most frequently caught endangered groups with a total of 71.43 %, which represents a significant proportion of the total bycatch of endangered species and indicates considerable pressure on these groups. On the other hand, sea turtles account for 28.57 % of the total bycatch. One of the most important aspects of this study is the survival rate of these groups after capture and release back into the sea. According to the data collected in this study, the survival rate for sharks and rays was 73.33 %, while the survival rate for sea turtles was as high as 83.33 %. It is important to note that marine mammals and birds were not included in the bycatch when considering vulnerable groups of marine organisms. This research has demonstrated the importance of developing and applying fishing techniques that reduce bycatch, and the importance of ongoing monitoring and research to understand the long-term effects of bycatch on different populations of marine organisms. This includes developing more selective fishing techniques, improving animal handling practices and strengthening the legal framework and oversight to ensure the sustainability of fishing activities and better protection of marine ecosystems.