Ms Ayşe Haruka Oshima Açıkbaş1, Prof. James Davis Reimer2, Prof. Timothy Ravasi1
1Okinawa Institute of Science and Technology, Onna, Japan, 2University of Ryukyus, Nishihara, Japan
Biography:
Ayşe Haruka Oshima Açıkbaş is a PhD candidate at the Okinawa Institute of Science and Technology, where she is studying environmental DNA methods in marine biology. Her research focuses on understanding range-shifts in marine species along Japanese coastlines through eDNA metabarcoding. Under the supervision of Prof. Timothy Ravasi and other experts, she has been involved in fieldwork and lab work, including surveys of isolated islands and monitoring nearshore reef sites. Ayşe has contributed to research on marine biodiversity and participated in various conferences and projects, such as the TARA JAMBIO Blue Carbon Project. Her work is documented in publications and presentations at international symposia.
Abstract:
The marine realm is undergoing rapid transformations due to global climate change at multiple interlinked levels from the biogeochemical make-up of the oceans to the distributions of organisms. Range shifts of marine fish species under the changing ocean conditions lead to novel assemblage compositions, with anticipated and observed downstream effects on ecosystem services. Frequently cited as one of the drivers of such marine range shifts, western boundary currents (WBCs) have been shown to create ocean warming hotspots and transport tropical species poleward from tropical to temperate regions along latitudinal gradients. The Kuroshio Current is one such WBC that flows along the Pacific coastline of Japan, where reports of non-native tropical species and their successful overwintering in sink locations continue to accumulate. As Japanese coastal ecosystems continue to drastically shift, there is need to closely monitor and understand these changes to mitigate their impacts. Here, we conducted a comprehensive environmental DNA (eDNA) metabarcoding survey targeting the fish assemblages of Japan’s tropicalizing habitats in order to characterize this temporal process. A comprehensive eDNA databank has been established and is open for use by collaborators who wish to focus on different taxa to achieve a wider picture on the phenomenon. We introduce our analyses of the fish assemblages from sampling sites both directly under and removed from the influence of the Kuroshio Current, and discuss the proposed tropicalizing effect of the Kuroshio Current.