Southernmost records of two Seriola species in an Australian ocean-warming hotspot

Changes in marine species distributions in response to climate warming are being observed globally. However, there is great variation in the magnitude and rate of species responses. South-eastern Australia represents a global hotspot for ocean warming and, subsequently, numerous poleward extensions in marine species distributions are evident within the region. We report on two species of Carangid not previously found in this region, recorded through photo-verified observations by citizen scientists. This includes the first record of Amberjack (Seriola dumerili) in eastern Tasmania and an extension of the previously most southern reported observation of a similarly mobile congener, the Yellowtail kingfish (Seriola lalandi) along south-eastern Tasmania. Out-of-range observations may simply represent vagrant individuals; however, there is also evidence that they are often indicators of future colonisation potential. Moreover, the observations presented here are potentially representative of a range of climate-driven changes to marine biodiversity in this region and highlight the utility of community observations in acting as an effective early-warning system for reporting changes in the marine environment. Early detection and reporting of distributional changes are important for proactive environmental management, and is enhanced by establishing an informed community and mechanisms for conveying these observations to science and management authorities.