Japanese Shigenori Goto said he found the 13ft long squid swimming in one of his fixed nets off the island in Niigata Prefecture when he hauled it in early on Wednesday morning.
The squid, later found to be male, reportedly died after being brought to the surface.
According to Mr Goto, the net, set to catch Japanese amberjack, was placed at a depth of around 70m deep about two-thirds of a mile from the coast.
“This is the first time I’ve seen such a large squid,” he told local media in Japan.
The squid was taken to a local government marine research institute in Niigata for research.
Source: The Telegraph