Growing grassroots awareness also helps protect the habitat for the swans.

Tanchos, 47, is an ethnic Tibetan and runs a home guesthouse and a restaurant close to the lake. With more than 20 tents and 30 rooms, he receives 150 guests a day in peak season, usually in June.

In 2011, he accompanied more than 10 different groups of guests to see the swans. Familiar with the surroundings, he always found spots free of charge offering close-up observation.

This year, he expects a similar number of guests, although he has been told he is one of the few people who does not charge for bird-watching.

His village has more than 1,000 residents, mostly ethnic Tibetans, who do not eat fish and are kind to animals. Yet the scaleless carp, a special product of Qinghai Lake, is being clandestinely fished out, despite a government ban in 2001 on the endangered species under second-class State protection due to overfishing.

A scaleless carp weighing less than 1 kg can sell for 200 yuan.

Tanchos said he has met guests who wish to try the specialty. Driven by profits, some disregard the ban and fish for the carp for profit.

Song Shengtang, 56, a retired police officer in Xining, had similar experiences. He began receiving visitors on driving tours in 2006, charging 600 yuan a day. He saw very small carps were being fished, with authorities often turning a blind eye.

Stricter enforcement of the fishing ban should be adopted, Song said.

Although whooper swans do not eat scaleless carp, the fish is a vital link in the food chain as many other birds feed on it. Abundant carp can help small aquatic animals flourish and help restore the lake's biodiversity, said protection chief Wu Yonglin.

According to the Qinghai province department of agriculture and animal husbandry, more than 35,000 tons of scaleless carp live in the lake, 13.5 times the amount in 2002.

The province dealt with 34 violations of the fishing ban, confiscated 4,422 kg of illegal harvests, and destroyed 4,500 pieces of fishing equipment this year, Xinhua News Agency reported on Nov 28.

liyao@chinadaily.com.cn