Lack of food, pollution or weather change may affect the iconic turtle at the Hoan Kiem Lake in Hanoi, as the turtle has surfaced very often.

Since the turtle returned to the lake in July, it has surfaced many times, with at least 12 times in November and four times in early days of December, according to notes by Prof. Dr. Ha Dinh Duc, who has kept track of the turtle for decades.

Dr. Nguyen Viet Vinh, an aquatic expert, said that the iconic turtle rose to the surface because it was hungry.

“The volume of fish released to the lake as living food for the turtle is not much. It is uneasy for the turtle to catch the fish, especially when the turtle was familiar to be fed while it was in the tank during the three-month treatment period,” Vinh said.

Another expert, Dr. Bui Quang Te, also said that it is highly possible that the turtle lacks food, but he added that the animal may surface due to other factors, including pollution or weather change.

Dr. Ha Dinh Duc said that this is the dry season. Under the sunlight, algae develops strongly and causes a sharp decrease of oxygen in the water. The turtle has to surface to breathe.

Before the turtle was brought back to the lake in July, around 60,000 fish were released to the lake as food for the turtle. While being treated in a tank, the turtle ate around five fish a day.