Research groups at the University of Tokyo and Hokkaido University have revealed that juvenile and juvenile Japanese eels, which have been pointed out to be endangered, have been found one after another in rivers in Hokkaido, which had never been used as a habitat.
It is possible that the eel habitat is moving north due to the effects of climate change, so we will investigate it in detail.
According to the University of Tokyo and Hokkaido University, a survey was conducted in a river in the southwestern part of Hokkaido in May, and 16 Japanese eel fry, about 6 cm in length, were found.
For this reason, as a result of investigating the same river last year, in addition to 9 fry, more mature juveniles with a body length of about 20 cm were confirmed.
According to the research group, it is the first time that juvenile eels in the early stages of growth have been confirmed in Hokkaido, and this month's survey also found juveniles in other rivers in the same southwestern part of Hokkaido. ..
For this reason, the research group says that Hokkaido, which was not previously a habitat for eels, may become a new habitat due to the effects of climate change, and how eels grow in rivers in Hokkaido. I'm going to investigate the ecology in detail.
Associate Professor Mari Kuroki of the Graduate School of Interdisciplinary Information Studies, the University of Tokyo said, "If the earth warms in the future, Hokkaido may become an important habitat for eels. Is also important for conservation. "
The migration route of Japanese eels
Japanese eels inhabit East Asian regions such as Japan, China, South Korea, and Taiwan. It is thought to grow in rivers.
According to research groups at the University of Tokyo and Hokkaido University, the northern limit of habitat in Japan is Aomori Prefecture, and although there are few records in the past that grown eels were harvested in Hokkaido, they were once released. It was not known if it was a natural eel because it had been damaged.
The research group pointed out that the fry have reached the river in Hokkaido, and it is possible that the migration route is moving north due to the effects of climate change and other factors, such as the intensification of the Kuroshio Current and the rise in seawater temperature. Yes, and further investigation is needed.
In addition, a survey conducted in southwestern Hokkaido this month found that eels were collected along with salmon such as yamame trout and rainbow trout in a river with a water temperature of about 17 degrees Celsius.
Since the water temperature of the river in Hokkaido is lower than that of the main island and the food is different, the research group will investigate how eels grow in the river and whether the eels grown in Hokkaido have returned to the vicinity of the Mariana Islands for spawning. I also want to find out about.
The owner of a long-established eel restaurant "surprised"
The owner of a long-established eel restaurant in Chuo-ku, Sapporo, which has been in business for 74 years, said that he was surprised to find juvenile Japanese eels and juveniles in Hokkaido, "I thought the habitat was up to Aomori." rice field.
"Unagi Futaba" was crowded with a large number of customers from before noon on the 21st, before the summer earthen cattle day, and a man in his 80s in Sapporo who visited with a couple to eat eels said "in a year. I once come to eat eel at this time of year. It's delicious, isn't it? "
The store mainly purchases eels cultivated from fry in Kyushu and the Tokai region, and tries to purchase large-sized eels in order to make effective use of one eel.
However, this summer, the amount of eels in circulation is less than normal because the catching time of fry for the earthen cattle day was delayed and the aquaculture in the production area started late.
Yoshiaki Matsuno, the owner of the eel Futaba, said, "I was surprised to hear that the eel habitat is up to Aomori Prefecture. I think it is good for Hokkaido to become an eel habitat from the perspective of increasing resources." I was talking.