CHATTANOOGA (WRCB) - To help celebrate Earth Day, the Tennessee Aquarium reintroduced a native fish species into the Tennessee River.    

Students from Ivy Academy and UTV helped release 36 lake sturgeon Thursday afternoon.

Each fish is six to seven years old and weighs between 13 and 18 pounds. When fully grown, the lake sturgeon can reach eight feet in length and weigh over 300 pounds.

Lake sturgeon were found in Tennessee until about 1960.  Aquarium workers say habitat change, pollution and overfishing killed them off.

The Tennessee River has now been cleaned up and can support the fish again.

"While it may not matter that one particular species is back, it's really just a key ingredient to returning the entire ecosystem to a healthier friendlier place for all us," explains Dr. Anna George from the Tennessee Aquarium.

More than 108,000 fish have been reintroduced since the "Saving the Sturgeon" program began 11 years ago.