Sharks as long as a small bus prowl at the water's surface, their mouths open wide in search of lunch. And the crowd goes wild. That's been the scene lately off the coast of Southern California, where gentle giant basking sharks have been turning up in numbers not seen in 30 years, per the Ventura County Star. Known to feast on tiny copepods like plankton, the second-largest known shark species was common along the West Coast before commercial fishing took a toll beginning around the 1960s, reports the Los Angeles Times. But with their general whereabouts unknown, "we don't have enough data points nor enough basic information to say what is going on with their population with any confidence," NOAA marine biologist Heidi Dewar tells the San Francisco Chronicle. As the Times reports, only a handful of basking sharks have been tagged.
Scientists now hope for more opportunities for study with regular sightings of the sharks in the Santa Barbara Channel—and near Ventura, Santa Monica, and Long Beach—since April. A group of 10 to 20 sharks appear to be moving together, though there have been individual sightings, too. Until this year, Dan Salas of Long Beach's Harbor Breeze Cruises had only ever seen two basking sharks. Now he's seen five. "They're like the Loch Ness monster," but "the conditions are just perfect," he says, pointing to warm temperatures and freshwater runoff providing nutrients for plankton. However, runoff may have also fueled poisonous algae suspected in dolphin deaths in Orange County. More information should be available in the coming months as two basking sharks were tagged in April. The tags will later detach and float to the surface to transmit satellite data. (Read more sharks stories.)