Faith Johnstone says at least one local resident near Neste boat launch in Thunder Bay's Westfort neighbourhood has reported sightings of "thousands" of dead fish floating along the Kaministiquia River.

Johnstone, an environmental monitor for Fort William First Nation, says the resident observed the eerie scene over the span of three hours one day earlier this week.

It's been a common sighting in the past week for regular users of the dock and its adjacent walking paths, alongside strange odours …