Using environmental DNA analyses to assess the occurrence and abundance of the endangered amphidromous fish Plecoglossus altivelis ryukyuensis

Yoshihisa Akamatsu; Gen Kume; Masuji Gotou; Takanori Kono; Takuma Fujii; Ryutei Inui; Yoshihisa Kurita

doi:10.3897/BDJ.8.e39679

Using environmental DNA analyses to assess the occurrence and abundance of the endangered amphidromous fish Plecoglossus altivelis ryukyuensis

Biodivers Data J. 2020 Jan 14:8:e39679. doi: 10.3897/BDJ.8.e39679. eCollection 2020.

Authors

Yoshihisa Akamatsu¹, Gen Kume², Masuji Gotou¹, Takanori Kono¹, Takuma Fujii³, Ryutei Inui^{1

4}, Yoshihisa Kurita⁵

Affiliations

¹ Yamaguchi University, Ube, Japan Yamaguchi University Ube Japan.
² Kagoshima University, Kagoshima, Japan Kagoshima University Kagoshima Japan.
³ Kagoshima University, Amami, Japan Kagoshima University Amami Japan.
⁴ Fukuoka Institute of Technology, Fukuoka, Japan Fukuoka Institute of Technology Fukuoka Japan.
⁵ Kyushu University, Fukutsu, Japan Kyushu University Fukutsu Japan.

Abstract

The Ryukyu ayu Plecoglossus altivelis ryukyuensis is an endangered amphidromous fish that inhabits rivers in the Ryukyu Archipelago (Japan). Populations of the species have declined dramatically. Consequently, the Ryukyu ayu has been registered as a natural monument in Japan and monitoring surveys with direct catching are restricted legally. This restriction, unfortunately, makes monitoring of population abundances difficult and creates a barrier to both advancing understanding of the species' status and the development of appropriate conservation plans. We developed a non-invasive monitoring methodology using eDNA analyses. We designed a specific quantitative PCR assay for the Ryukyu ayu using the mitochondrial ND4 region. Using this primer/probe set, we conducted eDNA analyses in three rivers on Amami-Ohshima Island. The DNA fragments were amplified from the eDNA extracted from natural water in each river. The numbers of DNA fragments detected were positively correlated with individual counts of fish obtained by visual snorkelling surveys. Our method does not contravene restrictions and facilitates abundance monitoring of this endangered fish species.

Keywords: Monitoring methods; conservation; qPCR; stock management; threatened species.

Yoshihisa Akamatsu, Gen Kume, Masuji Gotou, Takanori Kono, Takuma Fujii, Ryutei Inui, Yoshihisa Kurita.

Grants and funding

This work was supported by JSPS KAKENHI Grant Number 16K07827. This work was supported by a grants-in-aid of "The Zoshinkai Fund For Protection of Endangered Animals, Japan."