Environmental DNA metabarcoding offers a unique perspective on circum-Antarctic fish community dynamics

Area of Science:

• Marine Biology
• Environmental DNA (eDNA) Metabarcoding
• Southern Ocean Ecosystems

Background:

• Antarctica's unique biodiversity is crucial but challenging to monitor due to its extreme environment.
• Effective biomonitoring methods are vital for the ecologically and economically important Southern Ocean.
• Environmental DNA (eDNA) metabarcoding offers a promising solution for monitoring in difficult-to-sample environments.

Purpose of the Study:

• To investigate fish species diversity and assemblages in the Southern Ocean using eDNA.
• To compare fish communities across Prydz Bay (PB), Cosmonaut Sea (CS), east Antarctic Peninsula (AP), and Amundsen-Bellingshausen Sea (ABS).
• To assess the utility of eDNA for understanding fish community dynamics in remote marine ecosystems.

Main Methods:

• Collected 121 eDNA samples from 65 stations across four distinct Southern Ocean regions.
• Utilized eDNA metabarcoding to identify fish species present in the samples.
• Analyzed fish species diversity, assemblages, and distribution patterns using statistical methods including cluster analysis.

Main Results:

• Detected 40 fish species across the studied areas, with regional variations in species richness (PB: 30, CS: 31, AP: 26, ABS: 31).
• Found significant differences in fish assemblages among the four regions, with the highest alpha diversity in the AP.
• Observed higher species richness and alpha diversity closer to land and in surface and bottom water layers.

Conclusions:

• eDNA metabarcoding is an effective tool for assessing fish diversity and community structure in the Southern Ocean.
• Fish assemblages vary significantly across different regions of the Southern Ocean.
• Sampling surface and bottom waters is recommended for comprehensive eDNA-based fish monitoring in challenging environments.