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Environmental DNA Metabarcoding for Monitoring Marine Fish Assemblages and Assessing “Tropicalizing” Range Shifts in Japan
https://doi.org/10.15102/0002001106
https://doi.org/10.15102/00020011064ccda3ce-4502-4a64-adf1-94efeb2656af
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OshimaAcikbas,AyseHarukaFulltext.pdf (8.4 MB)
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OshimaAcikbas,AyseHarukaExamAbstract.pdf (64 KB)
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| Item type | デフォルトアイテムタイプ（フル）(1) | |||||||||
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| PubDate | 2026-02-12 | |||||||||
| Title | ||||||||||
| Title | 環境DNAメタバーコーディングによる海産魚類群集のモニタリングと日本における「熱帯化」分布変化の評価 | |||||||||
| Language | ja | |||||||||
| Title | ||||||||||
| Title | Environmental DNA Metabarcoding for Monitoring Marine Fish Assemblages and Assessing “Tropicalizing” Range Shifts in Japan | |||||||||
| Language | en | |||||||||
| Creator |
Oshima Acikbas, Ayse Haruka
× Oshima Acikbas, Ayse Haruka
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| Access Rights | ||||||||||
| Access Rights | open access | |||||||||
| Access Rights URI | http://purl.org/coar/access_right/c_abf2 | |||||||||
| Rights | ||||||||||
| Rights | © 2026 The Author. | |||||||||
| Rights | ||||||||||
| Rights Resource | https://creativecommons.org/licenses/by-nc-nd/4.0/ | |||||||||
| Rights | Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International | |||||||||
| Subject | ||||||||||
| Subject Scheme | Other | |||||||||
| Subject | Marine Science | Climate Change | Tropical fish movements | eDNA metabarcoding | fish genetics and genomics | |||||||||
| Description | ||||||||||
| Description Type | Abstract | |||||||||
| Description | Marine biodiversity is redistributing due to climate change, necessitating the development of effective biomonitoring tools to understand and potentially mitigate the impacts. Environmental DNA (eDNA) metabarcoding is a highly scalable and non-invasive biodiversity survey method with the potential to accumulate large amounts of both assemblage and species occurrence data. In this thesis, I applied eDNA metabarcoding to analyze the marine fish assemblages and species occurrences across Japan and discuss the findings in comparison to the syntheses of ichthyological literature and reference databases, assessing the strengths and limitations of this method. A local-scale eDNA survey of the Ogasawara Islands across short intra-island group distances detected higher prevalence and relative abundance of the Scleractinia coral genera Acropora spp. in disagreement with past reports and provided novel occurrences for fish species and coral genera, representing a successful use-case of eDNA for efficient multi-taxa surveys of isolated, data-deficient ecosystems (Chapter 2). Consolidating multiple collaborative surveys and open access sequencing datasets resulted in possibly the largest fish eDNA dataset to date for Japan, enabling a nation-wide comparative assessment of sample completeness and fish assemblage diversity and evenness standardized by sampling coverage (Chapter 3). Most of the highly frequent species were detected across varying biogeographical zones and the obtained diversity patterns were mostly consistent with literature albeit with caveats. Mostly reef-associated or benthic Actinopterygii were detected, reflecting the sampling scheme almost exclusive to nearshore surfaces. Finally (Chapter 4), analysis of the eDNA occurrence records in comparison to the historical occurrence records and northern limit estimates from Aquamaps species distribution models and IUCN expert range maps showed that eDNA can detect high numbers of spatiotemporally resolved occurrences from marginal range edges: of the total 36,282 eDNA occurrence records, 1,337 (3.7%) were marginal for 193 species with regards to IUCN and 2,410 (6.6%) were marginal for 267 species with regards to Aquamaps. eDNA-sampling obtained novel latitudinal records and helped identify potentially outdated reference distribution ranges and limits for various commercially important species (e.g. Decapterus maruadsi, Epinephelus fasciatus, Pterocaesio spp.), cryptic taxa (e.g. Entomacrodus striatus, Enneapterygius philippinus), herbivores implicated in “isoyake” barrens (e.g. Siganus fuscescens, Calotomus japonicus, Prionurus scalprum) and overwintering seasonal vagrants (e.g. Ctenochaetus striatus, Sargocentron praslin, Acanthurus lineatus). Overall, this series of studies demonstrates the power and limitations of eDNA metabarcoding as a long-term tool for marine fish diversity assessment and tracking range extensions. Its scalability enables high spatiotemporal coverage to reveal local and national-scale biodiversity patterns (Chapter 2 and 3) and possibly better track species distribution range extensions contributing to tropicalization (Chapter 4). However, integration with traditional surveys and contextualization of the findings with literature and expert knowledge are key to interpretations and optimization of this method that is here to stay. |
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| Language | en | |||||||||
| Resource Type | ||||||||||
| Resource Type Identifier | http://purl.org/coar/resource_type/c_db06 | |||||||||
| Resource Type | doctoral thesis | |||||||||
| Version Type | ||||||||||
| Version Type | VoR | |||||||||
| Version Type Resource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||||
| Identifier Registration | ||||||||||
| Identifier Registration | 10.15102/0002001106 | |||||||||
| Identifier Registration Type | JaLC | |||||||||
| Dissertation Number | ||||||||||
| Dissertation Number | 甲第227号 | |||||||||
| Degree Name | ||||||||||
| Language | en | |||||||||
| Degree Name | Doctor of Philosophy | |||||||||
| Date Granted | ||||||||||
| Date Granted | 2026-01-31 | |||||||||
| Degree Grantor | ||||||||||
| Degree Grantor Name Identifier Scheme | kakenhi | |||||||||
| Degree Grantor Name Identifier | 38005 | |||||||||
| Language | en | |||||||||
| Degree Grantor Name | Okinawa Institute of Science and Technology Graduate University | |||||||||
