MONTEREY BAY >> For the first time in five years, a sperm whale has been sighted in the Monterey Bay.

The solitary adult male was first seen Oct. 1 by a Monterey Bay Whale Watch boat captain. It’s been spotted a handful of times since, in deep-water canyons relatively close to shore.

At 40- to 60-feet long, sperm whales are the largest toothed whale, with teeth the size of bananas. Their skin is gray and wrinkled, and their blowhole is on the left side of their head.

They can be found in all the world’s oceans, but are usually far offshore, hunting squid in deep waters. It’s rare to find one in the Monterey Bay, said Baldo Marinovic, research biologist with UC Santa Cruz’s Institute of Marine Sciences. The Monterey Bay has several types of squid, the main food source of sperm whales, he said.

“He’s definitely not here to mate,” said Marinovic. “If he’s hanging out here, it’s because he’s found a food source and he’s tapping into it. Or maybe occasionally, individuals get messed up and lost. It could be confused, who knows?”

Professional whale photographer Jodi Frediani, a Bonny Doon resident, has been on hundreds of Monterey Bay Whale Watch trips and never seen a sperm whale until this month.

“Sperm whales are deep divers and they can stay down for an hour at a time, so if you miss it, good luck,” Frediani said.

She described seeing a “wild, low, bushy blow” of water, angled to the left, the signature of a sperm whale.

“As soon as I saw it, it was clear that it wasn’t any whale I had seen before,” Frediani said.

Because sperm whales dive so deep, they take many breaths at the surface, unlike other whales which only take a few breaths. Frediani said she counted around three dozen blows before it fluked and dove again.

This male has distinctive scars on its right side, which is how whale watchers know it’s the same whale that’s been seen repeatedly.

Alisa Schulman-Janiger, a whale researcher with Monterey Bay Whale Watch, saw it on three occasions, on Oct. 11, 13 and 20. Before that, she’s hasn’t seen a sperm whale in the Monterey Bay in 30 years of whale watching, she said.

“You see a dark object laying at the surface, and the blows coming up again and again and again. And the blows are coming up at an angle. Then it arches up in the air really high and throws its tail up, like it’s standing on its head,” Schulman-Janiger said.

Mark Fischer, a marine acoustician, has audio recordings of the sperm whale taken this month with an underwater microphone that’s installed 2,700 feet deep, 20 miles offshore of Santa Cruz. It’s part of a project run by the Monterey Bay Aquarium Research Institute.

Sperm whales make clicking sounds to echo locate, similar to bats and dolphins. The clicks are around 200 decibels, louder than a jet engine at takeoff.

“If you’re on a small boat, you can hear it through the hull. That’s how loud they are,” Fischer said.

Unlike bats and dolphins which click at a high frequency, sperm whale clicks can be heard by the human ear.

“Because they (sperm whales) are so large, the clicks they make are much lower frequency. They have the largest sound-generating organ of any species on the planet, so these are pretty unusual clicks,” Fischer said.

Sperm Whale

What: A solitary male sperm whale has been sighted in Monterey Bay this month. It’s been five years since a sperm whale was spotted locally.

Description: The largest of all toothed whales, sperm whales can grow up to 40 feet long for females and 60 feet long for males. Their skin is gray and wrinkled and their blowhole is on the left side of the head.

Range: These whales are found throughout the world’s oceans and in the Mediterranean Sea, in deep waters.

Diet: Mostly squid.

Status: Federally listed as endangered.