Tokyo Tamagawa run-up Ayu drastically reduced Caused by typhoon No. 19 or June 2, 5:25
In the Tama River, which is known as an urban river where ayu goes up, it seems that the number of ayu that has run up this year is the smallest in the last 15 years, and it seems to have decreased sharply to about one-thirtieth of the year when it was the most. I understand. Experts in the survey pointed out that last year's typhoon may be the cause.
The Tama River once disappeared due to the deterioration of water quality, but with the improvement of the sewer system, nowadays it is known as a river where ayu go up.
Every spring, the Shimasho Agriculture, Forestry and Fisheries Research Center in Tokyo announces the estimated number of sweetfish that run up the Tama River based on the number of nets, and this year we surveyed from late March to the end of last month. ..
As a result, the number of sweetfish that went up this time was estimated to be about 370,000, which is about one-third of the number in 2012, which was the smallest and most common in the past 15 years.
Hiroshi Hashimoto of the Tokyo Metropolitan Shimasho Agriculture, Forestry and Fisheries Research Center said, "It is possible that the spawning grounds of ayu were damaged due to the effects of Typhoon No. 19 last October, and there were few spawners."
In the fishing cooperatives of the Tama River basin, Ayu by, for example, to develop a riverbed to prospect the early fall of this year to welcome the spawning season is about to want to advance create an environment, such as easy to lay eggs.