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River area biota investigation

Last update date July 15, 2020

Investigation summary

At environmental science research institute, we evaluate general water regime commencing with the river quality of the water of area of the sea in the city and investigate creature inhabiting river and the sea in the city for the purpose of having by showing the change of biota, citizen's raise interest in river and sea every about three years from 1973.
In river area, we investigated the 14th in 2014, 2015.
There is creature which came back to river of Yokohama while disappearing like sweetfish by improvement of the quality of the water by the sewer spread, improvement of river environment by fishway setting once during these nearly 40 years. The number of the classes of naturalized species increases while fish and prawns, types of brachyuran to come and go in river and the sea increased, and attention is necessary for future trend.

Investigation point

Investigation point is 6 water system 41 spots (the 2015 results) of river flowing through the city.

  • The Tsurumi River water system (12 spots)
  • Katabira River water system (four spots)
  • Large Okagawa water system (seven spots)
  • The Miya River water system (two spots)
  • Chamberlain river water system (three spots)
  • The Sakai River water system (13 spots include suburbs one spot)

Investigation contents

We investigate fish, benthos, waterweed, adhesion algae, the quality of the water and carry out the quality of the water evaluation of river from creature.
In late years we investigate one spot once each in the summer in winter.

Example of river living thing

Working papers

Accumulation, exhibition of living thing data

It is map to introduce point of creature investigation of river which Yokohama-shi goes to.
In the Tsurumi River, Katabira River, great Okagawa, the chamberlain River, you can see photograph of 6 water system 41 spots, the quality of the water evaluation result by biological indicator.

Inquiry to this page

Environmental Planning Bureau policy coordination department environmental science research institute

Telephone: 045-453-2550

Telephone: 045-453-2550

Fax: 045-453-2560

E-Mail address [email protected]

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Page ID: 327-274-135

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