Suchergebnisse

Environmental DNA (eDNA) is increasingly being used to assess community composition in marine ecosystems. Applying eDNA approaches across broad spatial scales now provide the potential to inform biogeographic analyses. However, to date, few studies have employed this technique to assess broad biogeographic patterns across multiple taxonomic groups. Here, we compare eDNA-derived communities of bony fishes and invertebrates, including corals and sponges, from 15 locations spanning the entire length of the Omani coast. This survey includes a variety of habitats, including coral and rocky reefs, and covers three distinct marine ecoregions. Our data support a known biogeographic break in fish communities between the north and the south of Oman; however, the eDNA data highlight that this faunal break is mostly reflected in schooling baitfish species (e.g., sardines and anchovies), whereas reef-associated fish communities appear more homogeneous along this coastline. Furthermore, our data provide indications that these biogeographic breaks also affect invertebrate communities, which includes corals, sponges, and broader eukaryotic groups. The observed community shifts were correlated with local environmental and anthropogenic differences characteristic of this coastline, particularly for the eDNA-derived bony fish communities. Overall, this study provides compelling support that eDNA sequencing and associated analyses may serve as powerful tools to detect community differences across biogeographic breaks and ecoregions, particularly in places where there is significant variation in oceanographic conditions or anthropogenic impacts. ; This research was supported by a Department of Foreign Affairs and Trade (DFAT) Council of Australian-Arab Relations (CAAR) grant to JDD, AH, MB, and AM, ARC Linkage Projects (LP160100839 and LP160101508) to JDD and MB, a Curtin University Early Career Research Fellowship (ECRF) to JDD, His Majesty's Trust Fund Strategic Research Grant (SR/AGR/FISH/18/01) to AM, and baseline research funds from the King Abdullah University of Science and Technology (KAUST) to MLB. For logistical support in Oman, we kindly thank the Ministry of Environment and Climate Affairs (collection permit number 6210/10/47), Ministry of Agriculture and Fisheries Wealth, Extra-Divers in Mirbat, and Ras Musandam Diver in Khasab, particularly Ali Hamed Saleh Al-Shaaili. The authors would also like to acknowledge staff and students of the TrEnD Laboratory, particularly Megan Coghlan and Adam Koziol, for DNA sequencing assistance; staff at eDNA Frontiers, particularly Rose Lines, Georgia Peverley, Tina Berry, and Shane Herbert, for DNA sequencing assistance; Adam Koziol and Katrina West for development of the CP1 and CP2 assays; Mahsa Mousavi Mousaviderazmahalleh and Georgia Nester for bioinformatic assistance; and Hugo Harrison for R scripting advice. This work was also supported by resources provided by the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia.

Macroalgae-dominated reefs are a prominent habitat in tropical seascapes that support a diversity of fishes, including fishery target species. To what extent, then, do macroalgal habitats contribute to small-scale tropical reef fisheries? To address this question we: (1) Quantified the macroalgae-associated fish component in catches from 133 small-scale fisheries, (2) Compared life-history traits relevant to fishing (e.g. growth, longevity) in macroalgal and coral-associated fishes, (3) Examined how macroalgae-associated species can influence catch diversity, trophic level and vulnerability and (4) Explored how tropical fisheries change with the expansion of macroalgal habitats using a case study of fishery-independent data for Seychelles. Fish that utilised macroalgal habitats comprise 24% of the catch, but very few fished species relied entirely on macroalgal or coral habitats post-settlement. Macroalgal and coral-associated fishes had similar life-history traits, although vulnerability to fishing declined with increasing contribution of macroalgae association to the catch, whilst mean trophic level and diversity peaked when macroalgal-associated fish accounted for 20%–30% of catches. The Seychelles case study revealed similar total fish biomass on macroalgal and coral reefs, although the biomass of primary target species increased as macroalgae cover expanded. Our findings reinforce that multiple habitat types are needed to support tropical fishery stability and sustainability. Whilst coral habitats have been the focus of tropical fisheries management, we show the potential for macroalgae-associated fish to support catch size and diversity in ways that reduce vulnerability to overfishing. This is pertinent to seascapes where repeated disturbances are facilitating the replacement of coral reef with macroalgal habitats. ; Maria Beger and an anonymous reviewer provided insightful comments on the manuscript. Support was provided by the WA Department of Biodiversity, Conservation & Attractions, Australian Institute of Marine Science, the Environment Conservation Fund of the Government of Hong Kong SAR (ECF15/2015 to PTYL and PKSL), the Philippine Department of Science and Technology Grants-in-Aid Program (to RAA and AAB), the Australian Research Council (DE130100688 to ASH), the Royal Society (UF140691 fellowship to NAJG), The Leverhulme Trust ( fellowship to JPWR) and the Swedish Research Council (2015–01257, E0344801).