Mosquito alert. Thought they were bad last summer? Get ready for squadrons of them.

The city's public health promotion committee has predicted the "mosquito density" will double this summer, compared to last year, and has called on Shanghai locals to breed mosquitofish in ponds and rivers to kill the larvae.

The warm and rainy weather in December and January has provided a favorable breeding environment for mosquitoes, the Shanghai Morning Post, reported yesterday.

Larvae are rarely found in Shanghai during February. But this year larvae has been widely found in puddles, construction sites, free markets and underground car parks.

Peng Guilan, a committee spokeswoman told China Daily that the mosquitofish was first introduced to Shanghai by authorities in the 1970s to kill larvae, but later chemical pesticides became more-widely used for convenience.

"Pesticides harms human health and is not environment-friendly," Peng said.

The mosquitofish originated from America and is a small fish no longer than 5 centimeters. It survives easily in small pools of water, and swallows as many as 200 larvae a day.

(China Daily February 28, 2007)