Mexico says it has successfully sedated and operated on three sea lions to remove fishing lines that that had threatened to strangle the marine mammals.

Mexico's office for environmental protection says the program has now successfully operated on a total of seven sea lions in the area around the island of Espiritu Santo, in the Baja California resort of La Paz.

The animals are sedated with acoustically-monitored darts, anesthesia and special procedures to allow the animals to be immediately returned to the wild.

The fishing lines often cut deeply into the sea lions' necks.

The office said Tuesday it is training personnel from the states of Sonora and Baja California, to extend the program to other areas.

Sea lions are considered a protected species in Mexico, but not endangered.