Large?scale eDNA metabarcoding survey reveals marine biogeographic break and transitions over tropical north?western Australia

Aim Environmental DNA (eDNA) metabarcoding has demonstrated its applicability as a highly sensitive biomonitoring tool across small spatial and temporal scales in marine ecosystems. However, it rarely been tested large or biogeographical barriers. Here, we scale up eDNA metabarcoding, test ability to detect major biogeographic break evaluate use regional Australia. Location North-western Australia (NWA). Methods We applied assays targeting the mitochondrial 16S rRNA CO1 genes 284 surface seawater samples collected from 71 mid-shelf, inshore, coastal nearshore estuarine sites over 700 km of NWA coastline. Results Metabarcoding detected wide range bony fish (404 taxa), elasmobranchs (44) aquatic reptiles (5). bioregional depth differentiation within inshore communities. These findings support presence break, which is purported occur vicinity Cape Leveque, demarcating border between Kimberley Canning bioregions. Inshore elasmobranch communities, well assemblages, were additionally found differ South North regions suggesting previously unrecognized subregional amongst these taxa. The overall compositional data have used update distribution information for number endangered, elusive data-deficient taxa, including sawfish (family: Pristidae), northern river shark (Glyphis garricki) wedgefish (genus: Rhynchobatus). Main conclusions high level sensitivity that was able discern fine-scale patterns large-scale, remote oceanographically complex region Importantly, this study highlights potential integrating broad-scale alongside other baseline surveys long-term monitoring approaches, are crucial sustainable management conservation biodiversity unique region.