Using vertebrate environmental DNA from seawater in biomonitoring of marine habitats

<p>Conservation and management of marine biodiversity depends on biomonitoring of marine habitats,<br> but current approaches are resource-intensive and require different approaches for different organisms. Environmental<br> DNA (eDNA) extracted from water samples is an efficient and versatile approach to detecting aquatic<br> animals. In the ocean, eDNA composition reflects local fauna at fine spatial scales, but little is known about the<br> effectiveness of eDNA-based monitoring of marine communities at larger scales. We investigated the potential of<br> eDNA to characterize and distinguish marine communities at large spatial scales by comparing vertebrate species<br> composition among marine habitats in Qatar, the Arabian Gulf (also known as the Persian Gulf), based on eDNA<br> metabarcoding of seawater samples. We conducted species accumulation analyses to estimate how much of the<br> vertebrate diversity we detected. We obtained eDNA sequences from a diverse assemblage of marine vertebrates,<br> spanning 191 taxa in 73 families. These included rare and endangered species and covered 36% of the bony fish<br> genera previously recorded in the gulf. Sites of similar habitat type were also similar in eDNA composition. The<br> species accumulation analyses showed that the number of sample replicates was insufficient for some sampling<br> sites but suggested that a few hundred eDNA samples could potentially capture &gt;90% of the marine vertebrate<br> diversity in the study area. Our results confirm that seawater samples contain habitat-characteristic molecular<br> signatures and that eDNA monitoring can efficiently cover vertebrate diversity at scales relevant to national and<br> regional conservation and management.</p>