Its demise is likely due to introduced fish species, grass carp.

They also complain that the state's remedy would kill all the fish in their ponds, not just the grass carp.

The grass carp is still a main delicacy in Hangzhou cuisine.

With the right amount of fish, the grass carp can keep the hydrilla trimmed for 20 years.

So far, the 1,600 grass carp released into Lake Austin have had no obvious effect.

Since 1991, the grass carp is no longer observed.

But it has become widespread throughout the world by means of introductions of the grass carp.

In more recent years, a number of grass carp was introduced to the river for aquatic weed control.

It was hoped that the introduction of grass carp would help to control the process.

He said proper stocking of grass carp would not harm other species.