FRANKLIN TWP, N.J. - A colony of invasive Chinese mussels left a township in Hunterdon County, New Jersey a little "shell-shocked".

But officials said the colony was wiped out before it could spread to the Delaware River and cause problems.

Officials said they're confident they've eradicated the mussels from a pond at a former fish farm in Franklin Township.

It's the first place in North America that the invasive mussels have surfaced.

They can grow to the size of footballs.

Officials said they hitched a ride to the US as larvae in the gills of Asian carp.

If they had spread to the Delaware River, they could have harmed a number of fish, such as shad and sturgeon