Doctors say if you want to lose weight, you need a healthy diet and more exercise. The same advice holds true at a marine life park in Beijing, where the nurse sharks have been over-nursing when they feed.

 

At the Blue Zoo near Workers' Stadium, the sharks have doubled their weight in the past eight years because the food comes too easily and they can't get enough exercise in the water pond where they live.

 

"A common 180-centimeter nurse shark has a girth of about 70 centimeters. But the nurse sharks in the park are almost twice the normal size," said Zhang Lihong, assistant to the director of the park, during an interview with China Central Television.

 

"When we feed them, they don't want to move their bodies at all," Zhang said, pointing at a shark with a big midriff.

 

"Their excess weight will lead to many problems with their health."

 

The nurse sharks have lived in the park since it opened in 1997. They've been well cared for, with specially made food and more rest hours, Zhang said. Evidently too much rest.

 

"We are very proud to see them growing well and gaining some weight," Zhang said. "But we didn't want to see them become ill because of excess weight."

 

In their natural habitat, nurse sharks have a long, slender shape. Their food species are not always easy to find in the sea. Usually, they eat only once or twice a month.

 

"Preying among competitive bottom dwellers consumes a lot of energy," Zhang said.

 

But in the park, the sharks live like kings and queens. They are fed big meals every day and don't have to move a fin.

 

"They become lazy and reluctant to move," Zhang said. "Gradually the sharks become wider in the middle and slender at each end."

 

So, to help them regain their slender figures, the park made up a diet plan and an exercise schedule.

 

Rule one: Eat less.

 

Park officials cut the sharks' meals from three a day to one. The problem was, after three days, they became hungry. Some smaller fish were disappearing, apparently the victims when the sharks got the munchies.

 

Then to protect these small fish, the staff changed the plan, feeding the sharks twice a day yet with the same amount of food. They also built more artificial shelters in the pond where small fish could hide if the sharks started chasing them.

 

Rule two: Eat more healthful food.

 

To maintain their energy and improve their immunity system, the staff added vitamins to the sharks' food.

 

Rule three: Exercise more.

 

Marine calisthenics consisted of leading the sharks around the pond while feeding them their fish.

 

So far, the plan seems to be working: Most of the sharks have shed about a quarter of their previous weight.

 

As Dory said in Finding Nemo: "Just keep swimming. Just keep swimming."

 

(China Daily January 5, 2007)