Durkalec says this can occur from time to time in Lake Erie in late summer when algae and other organic matter decompose. The decomposition uses up all the oxygen and creates what’s called a dead zone.

“What happens is when you have just the perfect storm of wind and current patterns, that water can well up or come up along the shoreline where it brings those accompanying strong methane odors and in some cases lots of dead fish as well,” says Durkalec.