GURNEE, Ill. — A kayaker fishing for salmon off Waukegan Harbor Monday morning found an unexpected animal in the water — a 4-foot-long caiman alligator.

Chicago resident David Castaneda had been paddling about four hours when around 9:30 a.m. he saw something floating in the water, he said. Thinking it was a dead salmon, he went closer to check.

Instead, he saw an alligator head, Castaneda said.

“I went closer to see if it was real,” he said. “I was just in shock. I wasn’t sure if it was a real alligator or a toy.”

Castaneda called 911 to report the animal and Waukegan’s Animal Control responded.

The animal, which had its mouth taped shut, “was definitely on borrowed time,” said Rob Carmichael, the curator for the Wildlife Discovery Center in Lake Forest, where the caiman is being taken.

“I would say it would be lucky if it lived another couple weeks,” Carmichael said. “Lake Michigan is only getting colder and colder each week.”

Caimans are part of the same family as alligators and crocodiles. They are relatively longer, more slender, and have more teeth than alligators.

Carmichael said he and a veterinarian will assess the caiman’s condition once it arrives.

It is unknown how long the animal was in the water with its mouth taped shut, he added, saying the caiman looked to be on the thin side from what he has seen so far.

He expects the Discovery Center to know within three to five days how serious the situation is, but as long as there aren’t any major issues like a bacterial infection, Carmichael said he thinks they should be able to get the animal turned around.

An investigation into whether the animal was abandoned, which is a crime, will “absolutely” be conducted, city spokesman David Motley said.

The abandoning of exotic animals is something that occurs less than it used to as a result of stepped-up state regulations about owning endangered or threatened animals.