This is one of the best times of the year to spot gray whales off the coast of Southern California as they migrate south for the winter. But recently, there have been an unusually high number of sightings of other whales.

"We've had so many whales," Dan "The Whale Man" Salas tells the guests on his boat. "This is all in the last two weeks. We've had orcas, we had a sperm whale, we've got humpback whales, blue whales, fin whales. Yesterday we had a massive pod of gray whales, so we never know what we're going to see out here."

It's like a whale traffic jam right now off the coast of Long Beach, Calif. — the nation's busiest commercial port. That has scientists puzzled, and whale watchers thrilled.

A Marine Mystery

One of the marine biologists aboard Salas' vessel is Dave Bader, director of education at the Aquarium of the Pacific.

Bader has been studying the annual gray whale migration off the tip of the Palos Verdes Peninsula for the past 15 years. Not far from these cliffs, the ocean floor drops off 1,000 feet, and gray whales park along the contour for a few days on their way south. They like to keep the land in sight, says Bader, because food is concentrated along the edges of that drop-off.

This year, scientists have also been spotting pods of orca whales, humpbacks, a sperm whale — the list goes on.

"The thing you would expect to see are gray whales migrating through," says Bader. "And the fact that we're getting a chance to see at this time of year fin whales, blue whales, is really a mystery."

Scientists like Bader who are looking to solve this mystery are considering a few theories. One is that climate change is causing currents to shift, sending billions of tons of squid and krill to this part of the coast. Basically, the whales have pulled off the highway and bellied up to the buffet.

Another theory is that this bay is getting cleaner and is supporting more marine life again; it used to be one of the most polluted bodies of water in the U.S.

"We knew they came through here, and we knew that they were there, but to see them in this abundance, we really don't know why," Bader says. "It could very well be that we've done a great job and the waters are better here off the coast — somehow that's attracting them. Maybe the populations themselves are growing. But the honest answer is, we don't know."

The only certainty is this is an amazing place to be right now. That is, if you can manage to see one of these creatures through all the giddy whale watchers.

Jill Walsh is taking the day off as a teacher's aide to celebrate her birthday out here.

"I've always wanted to see a whale. I've never got a chance; this was really interesting," Walsh says, pledging to return. "I'm going to take information to all the teachers and the students."

A classroom in the ocean — it's exactly what Bader wants to hear. The high number of whale sightings are drawing more people onto boats like this, and bringing more attention to the ocean as a whole. That's good for conservation, he says.

"I think in Los Angeles, we think of the wild as being a place that's very far away from us," Bader says. "You know, we have to travel to Alaska, or Hawaii, or South America, Central America, some place to get to the wild."

But all this time it's been right here, a few miles from a metro area of 20 million people.

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