PLUM ISLAND - Fishermen in the Antarctic waters south of New Zealand caught something unexpected recently when they hauled in a half-ton colossal squid more than 30 feet in length.

The squid, which died shortly after being caught, is thought to be the heaviest ever discovered. Steve O'Shea, a squid expert at the Auckland University of Technology, put the size of the squid in perspective this way: If the specimen were made into calamari rings, they would be the size of tractor tires.

The news of the squid discovery made headlines worldwide and brought back memories for Dan Laughlin, an assistant curator at Boston's New England Aquarium. In 1980, Laughlin was called in to work on a giant squid carcass that had washed up on Plum Island.

"It wasn't in great shape," Laughlin recalled. "It looked like it had been rolling around for a while."

But sightings of the little-understood deep-sea creatures are rare alive or dead and what was left of the Plum Island squid - soon nicknamed "Squidly" - was 14 feet long and weighed a quarter ton. Scientists determined the squid had originally been twice as long, about 30 feet. It was only the third giant squid found on American shores.

"It was a big deal," Laughlin said.

So the squid remains were transported to the aquarium and Laughlin spent days injecting every square inch of the jiggly mass with formalin to preserve it.

"I was on very intimate terms with that squid," Laughlin said, laughing. "More intimate than I cared to be."

The aquarium displayed the Plum Island squid for almost a year before sending it to the Smithsonian Institution in Washington, D.C. Squidly can still be seen today in a glass case at the National Museum of Natural History.

But even at 30 feet long, the Plum Island squid was small for its species. Scientists believe a full-grown giant squid can reach 60 feet in length, counting tentacles. Their eyeballs are the size of soccer balls.

In comparison to giant squid (Architeuthis dux), colossal squid (Mesonychoteuthis hamiltoni) are even more rarely found and even less understood. Giant squid, like the one found on Plum Island, are essentially overgrown cousins of the squid we commonly eat, with long, narrow bodies and equally long tentacles.

By comparison, colossal squid, like the one caught late last month, have shorter tentacles and a larger, more massive body. Their eyes are believed to be the biggest on Earth, perhaps growing up to 3 feet in diameter.

Both species have eight tentacles equipped with suction cups and two longer feeding arms. Both live at ocean depths so great - around 3,000 feet below the surface - there is no natural light.

The remains of the squid discovered last week have been frozen and will soon be displayed at the national museum of New Zealand.

A tale of two squids

Giant squid washed up on Plum Island Colossal squid caught off Antarctica

* Scientific name: Architeuthis dux Mesonychoteuthis hamiltoni

* Year found: 1980 2007

* Weight: 440 pounds 992 pounds

* Intact Length: 30 feet 33 feet

* Eye size: 10 inches in diameter 18 inches in diameter