According to a survey by Professor Hitoshi Araki of the Graduate School of Agriculture, Hokkaido University, it is possible that Ito, which is distributed only in Hokkaido but has decreased in number and is called a "phantom fish," inhabits seven rivers in Hokkaido. I found out.The DNA of Sakhalin taimen was detected in the water of the river, and it was revealed for the first time that two rivers have no cases of capture in the past and may inhabit.
According to Hokkaido University, a research group led by Professor Araki collected water from 2015 rivers in Hokkaido from 2018 to 120, and investigated whether DNA from Ito's dung and peeled epidermis was contained.
As a result, Ito's DNA was found in 7 rivers under the jurisdiction of Soya General Promotion Bureau in Northern Hokkaido, Rumoi Promotion Bureau, Kushiro General Promotion Bureau in Eastern Hokkaido, Tokachi General Promotion Bureau, Hidaka Promotion Bureau in Central Hokkaido, and Oshima General Promotion Bureau in Southern Hokkaido. rice field.However, 56% of the DNA found is under the jurisdiction of the Soya General Promotion Bureau in Northern Hokkaido, and 39% is under the jurisdiction of the Kushiro General Promotion Bureau in Eastern Hokkaido.Only a small amount was confirmed in other areas, and it was estimated that they were in danger of extinction.
By combining the topographical and land data of the Geographic Information System with the distribution map of Ito based on this analysis result, it was found that the basin has gentle undulations and wetlands and lagoons (* 1) exist as the environment in which Ito inhabits. ..
Sakhalin taimen is the largest freshwater fish in Japan classified in the Salmonid family.It has grown to over 1 meter in length, and once a big game over 2 meters was captured.It also lived in the Tohoku region in the past, but has already become extinct.Ito in Hokkaido is also classified as an endangered species on the Red List of the Ministry of the Environment.
* 1 Lagoon A place where the former sea was isolated from the open sea due to the development of sandbars and turned into a lake.
Paper information:[Frontiers in Ecology and Evolution] An environmental DNA survey on distribution of an endangered salmonid species
