Invasive Mussels Infiltrate Last Mussel-Free Great Lake

In a concerning development, invasive quagga and zebra mussels have been found in the remote Isle Royale National Park, the last Great Lake still largely free of the destructive species. As of August 2025, park scientists Lauren Isbell and Alex Egan recently discovered three adult mussels during a dive in Lake Superior, signaling a potential new foothold for the invasive bivalves.

The discovery has sent shockwaves through the scientific community, as Lake Superior was long considered immune to the mussel invasion that has devastated the other Great Lakes. However, new evidence of mussel larvae, or veligers, found in water samples across the lake has raised concerns that the mussels may be adapting to the calcium-poor conditions that were previously thought to inhibit their growth.

Experts fear that if the mussels gain a stronger foothold, they could wreak havoc on the lake's delicate ecosystem, disrupting the food chain and threatening the livelihoods of fishing communities that rely on the lake's abundant whitefish and other native species. Park staff are now racing to implement new biosecurity measures to prevent the further spread of mussels, but the vast size of Lake Superior and the constant influx of boats pose significant challenges.

Adding to the concerns is the potential impact of climate change, as warmer waters in the lake may be enabling the mussels to reproduce more successfully, further exacerbating the threat. Scientists are closely monitoring the situation and exploring new technologies that could help control the invasive species, but for now, the future of Lake Superior's pristine waters hangs in the balance.