First use of oceanic environmental DNA to study the spawning ecology of the Japanese eel Anguilla japonica

Takeuchi, Aya; Watanabe, Shun; Yamamoto, Satoshi; Miller, Michael J.; Fukuba, Tatsuhiro; Miwa, Tetsuya; Okino, Tatsufumi; Minamoto, Toshifumi; Tsukamoto, Katsumi

doi:10.3354/meps12828

Cited by 35 publications

(33 citation statements)

References 44 publications

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“…This makes it unfeasible to infer the presence of Japanese eels or the occurrence of their spawning activities during eDNA oceanic surveys. Our detection of Japanese eel eDNA in the spawning area indicated that eels could be present near the water sampling sites but it did not provide evidence of the spawning activities 14 . Not enough is known yet about the nature of eDNA to be able to infer that spawning events have occurred, such as how long does the eDNA persist, how much does the eDNA concentration change between before and after spawning, and what is the effect of life history stages on eDNA concentrations.…”

Section: Introductionmentioning

confidence: 62%

“…The eDNA concentration released from Japanese eels, degradation and dilution with distance from release, and depth and time of eDNA detection all need to be factored into the water sampling design and interpretation of results of oceanic surveys in the spawning area. Our detection of Japanese eel eDNA during a previous survey using a real-time PCR system (not qPCR) after the spawning had likely finished was difficult to interpret 14 . However, the deep depths of the detections (200–400 m) suggested that the eDNA was likely from adults and not from larvae since preleptocephali can be found in the shallower waters less than 200 m. Our findings about eDNA concentration from each life history stage of the Japanese eel and from spawning activities provide valuable criteria to assist in evaluating quantitative data of eDNA that could be obtained from oceanic surveys.…”

Section: Discussionmentioning

confidence: 87%

“…These species are closely related to the Japanese eel and could be present around the spawning area of the Japanese eel. The same primers and probe also enabled us to specifically detect eDNA of the Japanese eel from a tank and the open ocean 14 . Each 10 µL qPCR reaction consisted of 500 nM of each primer, 1.9 µL of H 2 O PCR grade (Roche), 100 nM of a hydrolysis probe, 5 µL of 2 × Master Mix (Roche) and 2 µL of an eDNA extract as a template.…”

Section: Methodsmentioning

confidence: 99%

“…Another technique has been used during recent oceanic surveys we conducted in the Japanese eel spawning area, which is to analyze environmental DNA (eDNA) from water samples to search for the presence of the adult eels. The water sampling, filtration, extraction and PCR system for the eDNA analysis worked successfully on board during an oceanic survey, and we could detect eDNA of the Japanese eel from 2 L seawater samples from water depths at 250 and 400 m using real-time PCR (not qPCR) 14 . This indicated that the onboard eDNA analysis was a viable technique for identifying locations or depths where Japanese eels may be within their spawning area during an oceanic survey.…”

Section: Introductionmentioning

confidence: 99%

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Release of eDNA by different life history stages and during spawning activities of laboratory-reared Japanese eels for interpretation of oceanic survey data

Takeuchi

Iijima

Kakuzen

et al. 2019

Sci Rep

104

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To assist in detection of offshore spawning activities of the Japanese eel Anguilla japonica and facilitate interpretation of results of environmental DNA (eDNA) analysis in their spawning area, we examined the eDNA concentration released by each life history stage of artificially reared Japanese eels in the laboratory using quantitative real-time PCR (qPCR). We also compared eDNA concentrations between before and after artificially induced spawning activities. eDNA was not detected from three 30 L seawater tanks containing each single fertilized egg, but eDNA was found from other tanks each containing single individuals of larval stages (preleptocephalus and leptocephalus), juvenile stages (glass eel, elver and yellow eel) or adult stage (silver eel). The eDNA concentrations increased in the life history stages, showed a significant difference among all stages, and were positively correlated with the total length and wet weight. Moreover, the eDNA concentration after spawning was 10–200 times higher than that before spawning, which indicated that the spawning events in the ocean would produce relatively high eDNA concentration. These results in the laboratory suggested that eDNA analysis appears to be an effective method for assisting oceanic surveys to estimate the presence and spawning events of the Japanese eel in the spawning area.

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Section: Introductionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Release of eDNA by different life history stages and during spawning activities of laboratory-reared Japanese eels for interpretation of oceanic survey data

Takeuchi

Iijima

Kakuzen

et al. 2019

Sci Rep

104

View full text Add to dashboard Cite

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“…The remarkable migrations and fossorial life styles make it difficult to observe them in aquatic environments and monitor their presence or absence. A species-specific method to detect DNA from fish stomachs and eDNA has been already used for A. anguilla 25,26 and A. japonica 27 to begin to overcome these difficulties.…”

Section: Introductionmentioning

confidence: 99%

New PCR primers for metabarcoding environmental DNA from freshwater eels, genus Anguilla

Takeuchi¹,

Sadõ²,

Gotoh³

et al. 2019

Sci Rep

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Freshwater eels of the genus Anguilla comprise 16 species that include three subspecies and are characterized by their unique catadromous life cycles. Their life histories and nocturnal life styles make it difficult to observe them in freshwater and marine habitats. To investigate their distribution and ecology in aquatic environments, we developed new PCR primers for metabarcoding environmental DNA (eDNA) from Anguilla . The new primers (MiEel) were designed for two conserved regions of the mitochondrial ATP6 gene, which amplify a variable region with sufficient interspecific variations ranging from five to 22 nucleotide differences (one to three nucleotide differences between three subspecies pairs). We confirmed the versatility of the MiEel primers for all freshwater eels using tissue DNA extracts when analyzed separately. The metabarcoding combined with the MiEel primers using mock communities enabled simultaneous detection of Anguilla at the species level. Analysis of eDNA samples from aquarium tanks, a controlled pond and natural rivers demonstrated that the MiEel metabarcoding could successfully detect the correct Anguilla species from water samples. These results suggested that eDNA metabarcoding with MiEel primers would be useful for non-invasively monitoring the presence of the endangered anguillid eels in aquatic environments where sampling surveys are difficult.

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Spawning Areas

Miller

2023

Fisheries Science Series

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First use of oceanic environmental DNA to study the spawning ecology of the Japanese eel Anguilla japonica

Cited by 35 publications

References 44 publications

Release of eDNA by different life history stages and during spawning activities of laboratory-reared Japanese eels for interpretation of oceanic survey data

Release of eDNA by different life history stages and during spawning activities of laboratory-reared Japanese eels for interpretation of oceanic survey data

New PCR primers for metabarcoding environmental DNA from freshwater eels, genus Anguilla

Spawning Areas

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