” The National Institute for Environmental Studies (NIES) revealed that the total number of sessile species, such as barnacles and snails, has been decreasing significantly along the coast within 10 kilometers south of the Fukushima No. 1 nuclear power plant since the accident there in 2011.
Although the exact relevance to the accident is unclear, according to the institute’s analysis there is the possibility that the mass death of sessile species was influenced by radioactive materials released into the sea.
The NIES gathered sessile species attached to tetrapods from seven survey points 50 centimeters square within the limits in Fukushima, Miyagi and Ibaraki prefectures in May and June 2013. Four of the survey points are located in Fukushima Prefecture. The institute then investigated species numbers among other details.
Concerning the survey points in Fukushima, the numbers at the two sites south of the power plant were much lower than the numbers at the two northern sites. Extrapolated into one square meter, 2,864 sessile creatures were confirmed at the survey point in Okuma, which is 1.2 kilometers south from the power plant. At the survey point in Tomioka, which is 9.5 kilometers south of the plant, 2,404 creatures were confirmed. Meanwhile, the average number of sessile creatures in the other five locations reached 18,592, with 31,728 in Minami-Soma and 5,324 in Futaba, both in Fukushima Prefecture and north of the power plant. ”