Presentation Information
[P01-049]Environmental DNA Monitoring Reveals Changes in Coastal Communities Associated with Shifts in the Kuroshio Extension Pathway
○Kaito Shin1 (1. Tohoku University (Japan))
Keywords:
Environmental DNA (eDNA),Coastal fish communities;,Ocean current
[Purpose] Changes in ocean current pathways are increasingly becoming a major driver of recent marine environmental change. In coastal areas, shifts in current pathways are known to cause rapid and localized environmental fluctuations. However, the effects of such abrupt environmental changes on coastal biological communities remain poorly understood. In this study, we investigated temporal changes in coastal fish communities in the Sanriku region of Japan, where a rapid increase in seawater temperature has been observed in association with recent shifts in the pathway of the Kuroshio Extension.
[Methode] Community composition was analyzed using environmental DNA (eDNA) metabarcoding data. eDNA allows the detection of many species because of its high sensitivity. In addition, this method’s simplicity and non-invasive nature enable surveys to be conducted more frequently than with conventional sampling approaches. In the Sanriku region, we conducted the surveys at 54 sites over multiple years. Multivariate analyses were performed to examine patterns in community composition.
[Results] Comparisons of seasonal communities between 2023 and 2024 revealed that community composition differed significantly between years in the Sanriku region. This difference was significant across all seasons. Species that increased from 2023 to 2024 included southern species such as Canthigaster rivulata and Lateolabrax latus. Notably, L. latus had not been previously detected in the Sanriku region.
[Consideration] The observed shifts in community composition and the increased detection of southern species suggest that different coastal fish communities occurred in the Sanriku region in 2024. However, these community changes could not be fully explained by local temperature changes alone. The increase in southern species may reflect changes in dispersal processes mediated by ocean currents, possibly associated with shifts in the pathway of the Kuroshio Extension that altered fish transport processes. In this presentation, additional analyses of Kuroshio Extension pathway variability will be conducted to further examine the relationship between ocean currents and coastal fish communities.
[Conclusion] This study revealed a clear shift in coastal fish community composition in the Sanriku region between 2023 and 2024 based on large-scale environmental DNA surveys. The observed community shift was accompanied by an increase in southern species, which may reflect changes in dispersal processes associated with shifts in ocean current pathways. These results suggest that the state of ocean currents can play an important role in structuring coastal fish communities. Furthermore, our findings highlight the potential of eDNA-based monitoring for detecting links between marine community dynamics and changes in oceanographic conditions such as current pathway variability.
[Methode] Community composition was analyzed using environmental DNA (eDNA) metabarcoding data. eDNA allows the detection of many species because of its high sensitivity. In addition, this method’s simplicity and non-invasive nature enable surveys to be conducted more frequently than with conventional sampling approaches. In the Sanriku region, we conducted the surveys at 54 sites over multiple years. Multivariate analyses were performed to examine patterns in community composition.
[Results] Comparisons of seasonal communities between 2023 and 2024 revealed that community composition differed significantly between years in the Sanriku region. This difference was significant across all seasons. Species that increased from 2023 to 2024 included southern species such as Canthigaster rivulata and Lateolabrax latus. Notably, L. latus had not been previously detected in the Sanriku region.
[Consideration] The observed shifts in community composition and the increased detection of southern species suggest that different coastal fish communities occurred in the Sanriku region in 2024. However, these community changes could not be fully explained by local temperature changes alone. The increase in southern species may reflect changes in dispersal processes mediated by ocean currents, possibly associated with shifts in the pathway of the Kuroshio Extension that altered fish transport processes. In this presentation, additional analyses of Kuroshio Extension pathway variability will be conducted to further examine the relationship between ocean currents and coastal fish communities.
[Conclusion] This study revealed a clear shift in coastal fish community composition in the Sanriku region between 2023 and 2024 based on large-scale environmental DNA surveys. The observed community shift was accompanied by an increase in southern species, which may reflect changes in dispersal processes associated with shifts in ocean current pathways. These results suggest that the state of ocean currents can play an important role in structuring coastal fish communities. Furthermore, our findings highlight the potential of eDNA-based monitoring for detecting links between marine community dynamics and changes in oceanographic conditions such as current pathway variability.
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