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Location Japan, Hokkaido
Central coordinates 141o 45.00' East  45o 22.00' North
IBA criteria A4i
Area 830 ha
Altitude 0 - 5m
Year of IBA assessment 2004

Wild Bird Society of Japan

Site description Lake Koetoi-Onuma is located in the east of Wakkanai City, has a perimeter of 12 km around, and a maximum depth of 2.2 m. In 1958, the lake was connected with the sea by a flood prevention project that straightened the Koetoigawa river. There is abundant wildlife in the fresh water lake and the brackish water. Many birds breed here, and Tundra Swans and ducks stop over in spring and autumn migrating seasons.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Tundra Swan Cygnus columbianus passage  2004  present  A4i  Least Concern 

IBA Monitoring

2010 low not assessed low
Poor - based on little, or potentially unreliable/unrepresentative, data

Energy production and mining renewable energy likely in long term (beyond 4 years) small area/few individuals (<10%) no or imperceptible deterioration low

Whole area of site (>90%) covered by appropriate conservation designation  Unknown  Unknown  low 


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland)   -

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Recommended citation  BirdLife International (2015) Important Bird Areas factsheet: Lake Koetoi-Onuma. Downloaded from on 04/10/2015

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