(CBS) Tracking a mystery, Alisa Schulman-Janiger and other marine biologists follow an ocean footprint looking for the second largest mammal in the world, the fin whale.

Sightings of the fin whale - part of the family that includes the humpback and big blue whales - used to be a rarity in the Santa Monica Bay but not anymore. They're everywhere, reports CBS News Correspondent Sandra Hughes.

"The people who have done this, watching for 20, 25 years, have never seen anything like it," Schulman-Janiger, a marine biologist at the American Cetacean Society, told Hughes. "It's described as a forest of blows. Everywhere you look there are these columns of blows going into the air."

Marine biologists started tracking the fin whale for a census beginning Dec. 1, 2009.

"We've seen them 31 out of 31 days, so it's amazing," Schulman-Janiger told Hughes. "I don't know how long this is going to continue, but it's absolutely fabulous."

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