Press Release

September 9 , 2014

Fisheries Research Agency

A situation of homing migration on released salmon in the Tohoku Region in the year of the Great East Japan Earthquake

The Great East Japan Earthquake occurred on the Tohoku Region of Japan on March 11, 2011. During this time, juvenile salmon were being reared at many salmon hatcheries in this region. Tsunami triggered by the earthquake damaged the hatcheries, and thus, most of these fish in the hatcheries were killed. And there has been concern that the mortality of fry released before the quake was increased. Therefore, it is expected that the present year, i.e., the year when these earthquake-affected salmon (born in 2010) will return to the Tohoku Region as four-year-old fish, may see a decline in the number of salmon homing migration from the ocean.

The Fisheries Research Agency has decided to carry out the following activities in collaboration with the concerned prefectures:

1) Rapid assessment of the impact of the Great East Japan Earthquake on the homing migration status of salmon (born in 2010).

2) Data collection and preliminary report of salmon provide.

Fig. 1 Changes in the number of juvenile salmon released (line graph) and returned (bar graph) along the Pacific coasts of the Tohoku Region (1970-2013)
(The number of salmon released in the fiscal year 2010 [i.e., spring of 2011] is not known due to the earthquake, and the report on the number of salmon released in the fiscal year 2013 is under preparation.)