Thousands of tonnes of dead fish wash up on beach and nobody knows why

Credit: Heal the Bay

Thousands of tons of dead fish have washed up on a beach in northern Japan and nobody knows why.

The haul – mostly sardines and some mackerel – washed ashore in Hakodate on the northernmost main island of Hokkaido on Thursday morning.

It created a sliver blanket stretching half a mile along the coastline.

Locals said they have never seen anything like it. Officials posted a warning online urging people not to consume the fish after some bagged them up to eat or sell.