In recent years, the amount of tiger puffer fish landed off the coast of Fukushima Prefecture has increased rapidly, but the detailed cause is unknown. In order to investigate its ecology, Fukushima University and others released a tiger puffer fish with a tracking device last year, and this month it was found that it was caught off the coast of Chiba Prefecture, nearly 400 kilometers away. Experts have analyzed that tiger puffer fish do not overwinter off the coast of Fukushima Prefecture but migrate, leading to a sharp increase in landings.
Until 2018, the catch of tiger puffer fish off the coast of Fukushima Prefecture was less than 1 ton, but since 2019 it has continued to increase year by year, and last year it surged to more than 36 tons.
However, the detailed cause of the increase is unknown, and Associate Professor Toshihiro Wada of Fukushima University, who specializes in fish ecology, is conducting a survey.
In October and December last year, a total of 10 tiger puffers with tracking devices were released from the quay of Soma City, and one tiger puffer fish released on the 12th of this month was caught in a set net off the coast of Kamogawa City, Chiba Prefecture, nearly 20 kilometers to the southwest.
The captured tiger pufferfish was a male released in October last year, and although it had lost 4% of its weight, it was in good condition.
On the other hand, in breeding tests conducted by prefectural research institutes since December last year to verify whether tiger puffers can survive the winter off the coast of Fukushima Prefecture, almost all of them have died so far.
For this reason, Associate Professor Wada analyzes that tiger puffers do not overwinter off the coast of Fukushima Prefecture, but migrate from places where the water temperature is relatively high, such as off the coast of Chiba Prefecture, leading to a rapid increase in landings.
Associate Professor Wada says, "We have not yet seen the whole picture of where the tiger puffer fish that are coming to Fukushima come from, where they go, and where the spawning grounds are, but one puzzle may have been filled.