A Japanese fisherman has reeled in a huge wolfish and it is raising concerns about the effects that the Fukushima nuclear disaster in 2011 has had on the environment, reports Yahoo News.

According to Yahoo News, the gigantic fish was caught by one Hiroshi Hirasaka off the Island of Hokkaido, close to eastern Russia.

This is one of the largest wolffish ever discovered, reports Yahoo News.

The species usual only grow to around 112 cm and weigh 15kg - but the one found lurking beneath the Pacific Ocean was a staggering two metres long.

That is around twice the usual size - and its gaping mouth is large enough to fit a small child inside.

Fortunately these fish only eat crabs and molluscs but the sight of one of these in the water is enough to terrify any swimmer.

In fact, this wolffish may be eaten itself by Hirasaka - who posted the photos on Twitter.

He travels the world to eat strange creatures and has even written a book called ‘Exotic Fish Species: I Caught, Judged and Tried Eating’, reports Yahoo News.

He wrote about his latest catch: “It was worth flying to Shiretoko [Hokkaido] twice within three months. This guy is super cool!”

However, there are now concerns that the mutant wolffish is a result of radiation from the Fukushima nuclear disaster.

Three of the Fukushima’s six nuclear reactors went into meltdown in 2011 when the plant was hit by a tsunami - the result of a huge earthquake.