Thousands of tons of dead sardines have washed up on a beach in northern Japan for unknown reasons, officials said Friday.

The sardines and some mackerel washed ashore in Hakodate on Japan’s northernmost main island of Hokkaido on Thursday morning, creating a sliver blanket along a stretch of beach about a kilometer (0.6 mile) long.

Local residents said they have never seen anything like it. Some gathered the fish to sell or eat.

[I guess it wasn’t a grunion run like we used to get in CA. ~ Beege]