Chronology of the history of Marimo | ⑤ History of Marimo in Lake Akan and Other | Facility Guide | Marimo Exhibition Center in Lake Akan, Kushiro

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History of Marimo in Lake Akan

1897: Mr. Takiya Kawakami found some spherical green algae in Shurikomabetsu Bay of the lake.
1898: Mr. Takiya Kawakami released the Japanese name of this green alga as "Marimo" in a botanical journal.
1921: The Marimo was designated as a Japanese Natural Monument.
1924: A newspaper reported that Marimo was damaged by excessive water intake and lowered water level for hydropower generation, and by floating timber down through inflowing rivers.
1934: The area including Akan, Kussharo, Mashu and Onneto was designated the Akan National Park.
1941: The Marimo was disappeared from Shurikomabetsu Bay before this period.
1950: Dr. Misao Tatewaki reported that the Marimo was significantly damaged by drawdown in the wing season (early spring).
Local residents launched Humane Association for Marimo in Lake Akan and hosted the first Marimo Festival.
1952: The Marimo was designated as a Japanese Special Natural Monument.
1956: Dr. Yoshiji Yoshii confirmed a significant decrease in the Marimo population compared to investigations performed in 1919 and 1922.
1957: A watchman was stationed at Marimo security cottage built in previous year by Churui Bay.
1958: A large number of Marimo were washed ashore near the mouth of Churui River (May). Common reed grasses were transplanted at the lakeshore of Churui Bay (100 m in length, 7 m in width).
To prevent that Marimo was washed ashore, a long net (180 m in length) was installed at the shallow place (1 m in depth) of the Churui Bay.
Akan Town Hall and the Hokkaido Board of Education started ecological researches of Marimo during low-water level seasons (until 1961).
1961: A Marimo observation facility was newly placed on Churui Island due to a voluntary restriction on entering pleasure boats into Churui Bay.
1962: To prevent that Marimo was washed ashore, a levee (1.3 m in height, 2.6 m in width, 192 m in length) was installed on the lakeshore of Churui Bay.
1964: The Humane Association for Marimo in Lake Akan evolved into the Preservation Society of Marimo in Lake Akan with expansion of scale.
1965: A large amount of Marimo were washed ashore of Churui Bay due to a typhoon.
1966: The levee was extended by 100 m.
1973: A large amount of Marimo were washed ashore near the Akanko-onsen town due to strong north wind, and were collected and returned to Churui Bay by the residents (May).
1978: The Marimo Exhibition Center was newly built on Churui Island.
About ten thousand Marimo were washed ashore of Churui Bay due to strong wind.
1979: The Preservation Society of Marimo in Lake Akan evolved into the Conservation Society of Marimo in Lake Akan with expansion of the scale.
1984: The sludge accumulated on the lake bottom near Akanko-onsen town was removed by dredge (until 1988).
1986: Service of the newly built public sewage was started in the Akanko-onsen town.
1989: Regular testing for water quality at Marimo habitats was started in Churui and Kinetanpe Bays (until 1997).
1991: A biologist was staffed to the Akan Town Board of Education as the Marimo curator, and hosted the event that the public observe the Marimo habitat as a part of the Marimo Festival (continuing every year).
1993: Studies found that the decrease of Marimo population was caused by lack of underwater sunlight.
1994: A new event of observing Marimo habitat was started for children of the Akanko-onsen town (continuing every year).
1995: The Marimo Exhibition Center was fully renovated.
Akan Town Board of Education started the third comprehensive research project regarding Marimo and Lake Akan (until 1997).
Large amounts of Marimo were washed ashore of Churui Bay in November, and were returned to the offshore area using the flow of the Churui River by local residents.
1996: Studies found the mechanism of which the Marimo was washed ashore.
1997: Studies found a basic mechanism of which the Marimo developed into spherical aggregation.
A patent application on the method for artificial cultivation of Marimo was submitted (a joint research with Hokkaido Electric Power Company).
Lecture meeting introducing the outcomes and topics of Marimo research was held at the Marimo Festival (continuing every year).
On-ice observation in Marimo habitat was started as a graduation event for the third-year students of Akanko-onsen Junior High School (continuing every year).
The Marimo were listed as Threatened Species Category I in the Red List released by the Japanese Ministry of the Environment.
1998: Studies found that the Marimo was a member of different and unknown phylogenetic group from the family Cladophoraceae in existence.
Symposiums, special exhibitions, and other relevant events were held commemorating the 100th anniversary of the discovery of the Marimo.
1999: An international joint research project started (continued until 2004).
2002: A forum was held commemorating the 50th anniversary of the designation of Marimo as a the Japanese Special Natural Monument.
Many large Marimo over 30 cm in diameter were found, but most of them were washed ashore by typhoon in October.
2003: "Nihon Marimo Kikou", the running story about history and findings of the Marimo research, was started in a local newspaper, the Kushiro Shimbun.
2004: Akan Town Hall and Konsen Western Forest Management Office concluded a forest management agreement to protect the habitat of the Marimo.
2005: Lake Akan was inscribed as a registered wetland under the Ramsar Convention.
2006: Responding to the case of illegally digging up Marimo, Marimo Theft Prevention Liaison Conference was launched.
2007: "Midori Oukoku", the travel report of Marimo research in Lake Akan written by Dr. Makoto Nishimura called “the father of Marimo study”, was republished after it’s deciphered.
Many large Marimo were washed ashore of Churui Bay due to storm (October), and were returned to the lake by residents (December).
2009: The Marimo Festival and the Conservation Society of Marimo in Lake Akan celebrated their 60th anniversary.
The Conservation and Management Project of Marimo in Lake Akan was selected as a Biodiversity Conservation Projects of the Japanese Ministry of the Environment.
Marimo Conservation Council was founded by 22 public and private organizations to promote projects including Marimo growth tests, after constructive dissolution of the Marimo Theft Prevention Liaison Conference.
2010: A symposium commemorating the foundation of the Marimo Conservation Council was held.
The Conservation Society of Marimo in Lake Akan received an education award from Kushiro District Office of Education.
New Marimo colony (epilithic type) was found in Lake Panketo above Lake Akan.
The phenomenon of which large Marimo floated up to the water surface was observed for the first time, but seemed to be an unusual accident by the high temperature of this summer.
Research changed taxonomic affiliation of Marimo into a novel family Pithophoraceae.
2011: Many mid- and small-sized Marimo were washed ashore of Churui Bay (June). A photo exhibition titled "Protecting the Marimo of Lake Akan" was held.
The transparency in Lake Akan recorded the highest (about 9 m) since the start of observation in 1917.
Biogeographic study using DNA data found that the ancestry of Marimo seemed to be in the Japanese archipelago and to be dispersed into Europe as well as North America.
Monitoring study found that macrophytes grew thickly and was suppressing growth of Marimo in Churui Bay.
2012: An international symposium and relevant events were held commemorating the 60th anniversary of the designation of the Japanese Special Natural Monument of Marimo.
The Marimo Protection and Management Plan was published to provide guidelines for research and conservation activities of Marimo.
The Marimo Study Team, consisting of students and experts, reported outcomes of the experimental studies regarding cultivation condition of artificial Marimo balls and predation effect of an alien crayfish on Marimo filaments.
2013: The Marimo Conservation Council evolved into the Lake Akan Marimo Conservation Committee with expansion of the scale (24 public and private organizations).
The Marimo growth test restarted in Shurikomabetsu Bay where Marimo habitat disappeared in the beginning of the 20th century.
Monitoring indicated that distribution area of Marimo in Churui Bay was decreasing with excessive growth of macrophytes.
The Japanese Ministry of the Environment conducted first comprehensive field study for all lakes and ponds in the Akan area (continued until 2014).
Many Marimo were washed ashore of Churui Bay due to the strong southern wind brought about by storm (November), and were returned to the lake by residents (December).
2014: The Lake Akan Marimo Conservation Committee started a study for controlling the growth situation of massed macrophytes in Churui Bay.
The detailed life of Marimo in Lake Akan including a situation rotating by windwave was broadcast in a special TV program.
2015: The improvement cutting test of the macrophytes in Churui Bay was started by the Lake Akan Marimo Conservation Committee.