An elusive alligator gar caught by placing hooks with horse mackerel as bait in the outer moat of Nagoya Castle on May 17 (Video by Hideaki Sato)

NAGOYA--Some fearsome intruders have been kept at bay by Nagoya Castle’s moat over the centuries, but none quite like the latest to be captured there--a 1.4-meter-long alligator gar.

The carnivorous fish put up a good fight against captors for an hour before conceding defeat, exhausted, on May 17.

Weighing more than 30 kilograms, the uninvited guest was caught after the city government placed 20 fish hooks in the moat on May 15 following reports of sightings.

“After we floated the hooks with horse mackerel as bait to lure the alligator gar, we saw one of them move a lot, and then saw a dark shadow in the moat. We thought it must be the alligator gar,” said Tatsuya Noro of Nagoya biodiversity center.

“It put up fierce resistance, and eventually it took the four of us to capture it,” Noro added.

A massive alligator gar, characterized by an elongated mouth filled with sharp teeth, was first spotted in the moat in 2009.

City officials confirmed two of the creatures were lurking in the moat, and they volunteered to capture the elusive fish.

Since December, the city staff have inspected the castle’s outer moat daily with binoculars seeking the fugitive fish.

This year, members of the public said they saw a massive alligator gar in the moat on April 8.

In response to the eyewitness reports, city authorities installed a gill net in the moat twice in April, but to no avail.

As the carnivorous fish could prey on native species and pose a threat to the ecosystem, the Environment Ministry plans to designate the alligator gar, of North American origin, as an invasive alien species.

With one of the fugitive fish still on the loose in the moat, Nagoya Castle’s battle against the invaders is not over yet and the fish will continue to be tracked, according to the city government.

(This article was written by Hideaki Sato and Koichi Morohoshi.)