Just when you thought it was safe to go back in the water, a "monster "has reared from the depths to terrify us all-the ravenous alligator gar.

The fish was first sighted in the calm waters of Yunchan Lake in the city of Ruzhou in Central China's Henan province in mid-July, leading to a frantic mission to capture it that captivated the nation.

The species, native to parts of North America, is named after its resemblance to an alligator with its broad snout and nasty, pointy teeth. This particular specimen was only 80 centimeters long, but rumors have spread that they can grow as big as 3 meters. It has a voracious appetite and will gobble up anything as soon as look at it.

The reason for the desperate attempts to net the fish is because, to China, it is an alien species, and this means its existence in the wild could have a devastating impact on native species and the natural ecosystem.

Alien invasive species have caused chaos all over the world. In Queensland, Australia, the cane toad was introduced as an alien species to eat the beetles that were destroying the state's sugar cane crops. Things got out of hand. The cane toads multiplied like gremlins in a rain shower and now the entire country is overrun with them. With no natural predators in its environment, the cane toad kingdom spread unchallenged.

The same could happen in China with the alligator gar-nothing on the food chain would challenge its dominance.

Another example of this occurred in Florida in the United States. Someone decided to let their pet Burmese python roam free in the Everglades one day and then, boom, there was a python curled up in every bush and pond in the state.

And so, there is little wonder why the Chinese authorities were quick to capture the elusive alligator gar as soon as they possibly could.

A meeting was hurriedly called and the terrified townsfolk of Ruzhou gathered to brainstorm how and who was going to hunt down this aquatic interloper. No one could agree on a definitive solution, but then above the hullabaloo a grizzled old sea captain slowly scratched his nails along a chalkboard at the back of the room to get everyone's attention. The man spoke.

"I'll catch this bird for you, but it ain't gonna be easy. Bad fish. Swallow you whole."

Those at the meeting agreed this man was silly and so instead got a team of firefighters and civilians together to fish the fish out from Yunchan Lake.

But the sea captain was right, it wasn't easy. At first, they used sonar to scour the 6.7-hectare lake. Ten days after the start of the hunt, nothing. Next, they decided to drain the lake as much as they could to increase their chances. Still nothing. So, they upped their team to 50 people.

Anticipation grew, "where is this darned fish", people collectively thought.

A livestream was set up to follow the capture mission, attracting 37 million viewers.

Through a process of elimination, the alligator gar's last possible shelter was narrowed down to a 180-meter-long culvert with a depth of 20 meters.

It was now or never. A final push was organized but the team was forced back by the rain.

Finally, two alligator gars were caught and disposed of humanely, putting an end to the perilous affair.

"But, two?" you say, "I thought there was only one?"

The fight against alien invasive species is an ongoing one, so, like with monster movies, who knows what else lurks under the surface?

Contact the writer at owenfishwick@chinadaily.com.cn