Marine Environmental Science, Kasai Laboratory  

Conservation of Marine Environment and ecosystem
The air fills space over the land, while water in the sea. Geophysical dynamics governs both the motion of atmosphere and ocean, and their phenomena are similar. However, the characteristics of air and water are different, so that living organisms and ecosystems show different aspects between in the air and water. The unknown world is expanding under the sea, as direct observation is difficult for human. Estuaries provide valuable ecosystem service in the world. It is worth more than tropical rain forests. What happen in the sea? Why the phenomenon occurs? In our laboratory, we make observation in the filed and reveal nature in the sea, taking in information through the full five senses.


Main Building 213
3-1-1 Minato-Cho, Hakodate, Hokkaido, 041-8611, JAPAN
TEL: +81-138-40-8807
E-mail: akihide [at]


11 Sep 2021

'Watershed proportion of forest cover fostering the conservation of red-listed fish richness in estuaries' has been accepted in Conservation Biology

Lavergne E, Kume M, Ahn H, Henmi Y, Terashima Y, Ye F, Kameyama S, Kai Y, Kadowaki K, Yamashita Y, and Kasai A 

22 Jul 2021

'Intraspecific genetic variability and diurnal activity affect environmental DNA detection in Japanese eel' has been accepted in PLOSONE.

Takahashi S, Takada S, Yamanaka H, Masuda R and Kasai A

3 Feb 2021

'Distribution of Japanese eel Anguilla japonica revealed by environmental DNA' has been accepted in Frontiers Ecology and Revolution. 
Kasai A, Yamazaki A, Ahn H, Yamanaka H, Kameyama S, Masuda R, Azuma N, Kimura S, Karaki T, Kurokawa Y and Yamashita Y 

23 Nov 2020
'Factors structuring estuarine and coastal fish communities across Japan using environmental DNA metabarcoding' has been accepted in Ecological Indicators.
Kume M, Lavergne E, Ahn H, Terashima Y, Kadowaki K, Ye F, Kameyama S, Kai Y, Henmi Y, Yamashita Y, and Kasai A 

11 Nov 2020

'Traditional land use effects on nutrient export from watersheds to coastal seas' has been accepted in Nutrient Cycling in Agroecosystems

 Sugimoto R, Kasai A, Tait DR, Rihei T, Hirai T, Asai K, Tamura Y, and Yamashita Y

1 Oct 2020
An environmental DNA project collaborating with the Earthwatch Japan has started. We will collect coastal waters from all over Japan and investigate fish communities using environmental DNA. 

Earthwatch Japan
Coastal Fish eDNA Monitoring Project with Earthwatch Japan

28 Sep 2020
'Evaluation of biodiversity of five estuaries in Japan using environmental DNA metabarcoding method' has been accepted in PLOSONE

Ahn H, Kume M, Terashima Y, Ye F, Kameyama S, Miya M, Yamashita Y and Kasai A 

11 July 2020
'An illustrated manual for environmental DNA research: Water sampling guidelines and experimental protocols' has been accepted in Environmental DNA

Minamoto T, Miya M, Sado T, Seino S, Doi H, Kondoh M, Nakamura K, Takahara T, Yamamoto S, Yamanaka H, Araki H, Iwasaki W, Kasai A, Masuda R and Uchii K 

24 June 2020
'Estimating fish population abundance by integrating quantitative data on environmental DNA and hydrodynamic modelling' has been accepted in Molecular Ecology.
Fukaya K, Murakami H, Yoon S, Minami K, Osada Y, Yamamoto S, Masuda R, Kasai A, Miyashita K, Minamoto T and Kondoh M

6 March 2020

'The effect of temperature on environmental DNA degradation of Japanese eel' has been accepted in Fisheries Science.

Kasai A, Takada S, Yamazaki A, Masuda R and Yamanaka H 

25 November 2019
'Quantitative estimation of the ecosystem services supporting the growth of Japanese chum salmon' has been accepted in  Deep Sea Research Part II 

Karasawa Y, Ueno H, Tanisugi R, Dobashi R, Yoon S, Kasai A and Kiyota M 

13 October 2019
'Correlation of changes in seasonal distribution and catch of red sea bream Pagrus major with winter temperature in the eastern Seto Inland Sea, Japan (1972-2010)' has been published in Fisheries Oceanography 

Yamamoto M, Omi H, Yasue N and Kasai A

10 September 2019
'Winter monsoon promotes the transport of Japanese temperate bass Lateolabrax japonicus eggs and larvae toward the innermost part of Tango Bay, the Sea of Japan' has been published in Fisheries Oceanography.

Suzuki K, Fuji T, Kasai A, Itoh S, Kimura S and Yamashita Y

Research areas

  • Anthropogenic impacts on marine ecosystems
  • Biodiversity using environmental DNA 
  • Material cycle and marine ecosystem using stable isotope
  • Numerical modeling of marine ecosystem and transport of eggs and larvae


  • Scientific paper
  • Book
  • Report
  • Presentation
  • Keynote address

Laboratory Member

  • Professor
  • Researcher
  • Student

Research Photos

  • Field Observation
  • Laboratory
  • Observed fish
  • Social alignment
  • Investigation scenery