By John Ostapkovich

PHILADELPHIA (CBS) — Mussels are once again living in a Philadelphia waterway, but only thanks to human intervention.

READ MORE: 'Ya Fav Trashman' Terrill Haigler Presented With Congressional Citation

A joint project of the Tookany/Tacony Frankford Watershed Partnership and the Partnership for the Delaware Estuary has transferred 60 mussels from a plump bed in the Delaware River to Tacony Creek, where there were none remaining.

Julie Slavet, executive director of the watershed group, says mussels help with restoration of the environment.

READ MORE: 'Plus-Up' Stimulus Checks Going Out To Those Who Were Underpaid

“They filter water — that’s what they do, that’s how they get their food,” she explains. “These little guys are pretty old.  Most of them are a few decades old, which is kind of incredible.”

Each mussel was also numbered and given a small metal chip, allowing it to be located by a metal detector in this wait-and-watch phase.

Slavet says the health of the creek is in everyone’s hands, inasmuch as what goes into storm drains upstream soon swirls past these seeded mussels, for better or worse.

MORE NEWS: Watch The Derek Chauvin Trial Live

The next, longer-term phase is to find a way to grow mussels for broader seeding.