Presentation Information
[ACG68-P15]Fish community structure and its environmental drivers across the Bering and Chukchi Seas inferred from eDNA metabarcoding
*Tatsuya Kawakami1, Hiromichi Ueno1, Akihide Kasai1 (1.Hokkaido University)
Keywords:
Bering Sea,Chukchi Sea,environmental DNA,distribution shift
Previous studies have highlighted rapid changes in the marine ecosystem of the Arctic Ocean. One of the prominent changes is the redistribution of marine organisms, including fish. Because fish are highly susceptible to changes in water temperature, their distribution ranges are shifting northward in the Arctic Ocean, causing the expansion of boreal species while Arctic species experience habitat contraction. The decrease in sea ice extent, occurring concurrently with increasing temperatures, may reduce barriers limiting fish distribution and lead to their expansion in the Arctic. Despite the importance of comprehending the impact of global warming on these shifts, long-term monitoring data covering vast regions are critically lacking.
This study aimed to clarify the fish community structure and its environmental drivers across the Bering and Chukchi Seas. To achieve this, we utilized environmental DNA (eDNA) metabarcoding, which comprehensively detects fish eDNA to indirectly indicate their distribution. eDNA samples were collected in the Bering and Chukchi Seas during the ice-free season (August to September) by the R/V Mirai (JAMSTEC) research cruises from 2020 to 2022. Environmental parameters were obtained via an onboard continuous monitoring system and CTD observations. Cluster analysis and indirect gradient analysis based on non-metric multidimensional scaling (nMDS) were employed to investigate community structure and evaluate correlations with environmental factors.
Results from 2020 showed that fish communities were classified into three clusters, almost exclusively composed of (1) sites within the basin area of the Bering Sea, (2) a mixture of the continental shelf of the Bering Sea and the Chukchi Sea around the Bering Strait, and (3) the shelf and shelf slope areas of the Chukchi Sea. Cluster analyses in 2021 and 2022 reproduced this structure, indicating the presence of geographical species boundaries on the shelf slope of the Bering Sea and around the Bering Strait. Indirect gradient analysis suggested that this fish community structure was associated with multiple environmental factors, such as water temperature, chlorophyll a fluorescence, and topography.
This study successfully demonstrated the utility of eDNA in capturing fish diversity, community shifts, and environmental drivers across the Bering and Chukchi Seas. Furthermore, these results provide an essential baseline for evaluating the impacts of climate change in the Arctic. Combining eDNA data with oceanographic observations will contribute to improving species distribution models, enabling more plausible predictions of fish distribution shifts in response to ongoing global warming.
This study aimed to clarify the fish community structure and its environmental drivers across the Bering and Chukchi Seas. To achieve this, we utilized environmental DNA (eDNA) metabarcoding, which comprehensively detects fish eDNA to indirectly indicate their distribution. eDNA samples were collected in the Bering and Chukchi Seas during the ice-free season (August to September) by the R/V Mirai (JAMSTEC) research cruises from 2020 to 2022. Environmental parameters were obtained via an onboard continuous monitoring system and CTD observations. Cluster analysis and indirect gradient analysis based on non-metric multidimensional scaling (nMDS) were employed to investigate community structure and evaluate correlations with environmental factors.
Results from 2020 showed that fish communities were classified into three clusters, almost exclusively composed of (1) sites within the basin area of the Bering Sea, (2) a mixture of the continental shelf of the Bering Sea and the Chukchi Sea around the Bering Strait, and (3) the shelf and shelf slope areas of the Chukchi Sea. Cluster analyses in 2021 and 2022 reproduced this structure, indicating the presence of geographical species boundaries on the shelf slope of the Bering Sea and around the Bering Strait. Indirect gradient analysis suggested that this fish community structure was associated with multiple environmental factors, such as water temperature, chlorophyll a fluorescence, and topography.
This study successfully demonstrated the utility of eDNA in capturing fish diversity, community shifts, and environmental drivers across the Bering and Chukchi Seas. Furthermore, these results provide an essential baseline for evaluating the impacts of climate change in the Arctic. Combining eDNA data with oceanographic observations will contribute to improving species distribution models, enabling more plausible predictions of fish distribution shifts in response to ongoing global warming.