Larger foraging area means greater fisheries interaction risk for juvenile yellow-eyed penguins in their sub-Antarctic range

Abstract Seabird foraging success is crucial for individual survival and therefore also for recruitment, breeding success, and population stability. However, there is limited information on the movements of juvenile seabirds, including penguins. This study investigates the foraging range of juvenile yellow-eyed penguins from Enderby Island, in the sub-Antarctic Auckland Islands, and their overlap with protected areas where commercial fishing is prohibited. Two juvenile penguins were tracked using GPS-Argos tags, and their movements were compared to those of breeding adults. Juveniles travelled up to 275.2 km from the colony, significantly farther than the maximum 46.7 km for breeding adults. Juveniles also used a much larger foraging area of 18,027 km 2 , compared to 738 km 2 for adults. Only 7% of juvenile foraging occurred within the protected area, highlighting their potential vulnerability to commercial fishing activities. Juveniles had a 17% overlap with commercial fishing areas, compared to 4% for adults. The extensive foraging range and low overlap with protected areas suggest that juveniles are at higher risk of encountering threats, which may contribute to higher mortality rates. These findings underscore the need for conservation efforts to investigate and address threats in the broader foraging areas used by juveniles. Future research should track additional juvenile penguins and study prey availability to support effective conservation strategies for this endangered species.