A young Humboldt penguin that escaped from a Tokyo aquarium in March has been finally collared, the metropolitan government announced Thursday night.

The 1-year-old penguin, measuring 60 cm to 70 cm, was one of 135 at Tokyo Sea Life Park along the shore of Tokyo Bay in Edogawa Ward.

An aquarium employee patroling a stretch of the Edogawa River in Ichikawa, Chiba Prefecture, spotted the penguin, which was not in the water at the time, and caught it by hand at around 5:30 p.m., the metro government said.

Earlier this week, the penguin was seen swimming in the river near the Kanamachi water purification plant in Katsushika Ward.

Aquarium officials said earlier the facility is surrounded by a 2-meter-tall net to contain its penguins, but that there are gaps in the net that cats and frogs often pass through.