Weird 'Blobs' Turning Up on California Beaches One expert links these 'sea hares' to warmer water temperatures By Newser Editors and Wire Services Posted Jun 13, 2015 3:15 PM CDT 20 comments Comments File photo of a sea hare. (Shutterstock) (Newser) – A blob from the sea is invading East Bay beaches and waterways this summer, and some experts say it may be caused by warmer temperatures near coastal waters. These California sea hares are harmless plant eaters. But their big size and unusual abundance this year is turning heads at the shorelines in the cities of Crab Cove in Alameda and Miller Knox Regional Park in Richmond, as well as Lake Merritt in Oakland and Tomales Bay in Marin County, reports the Contra Costa Times. Officials have no precise count, but dozens have been seen on some beaches at the same time, and two dozen were spotted last month in an inlet to Lake Merritt in Oakland. "We are getting calls from the public asking what the heck is this big weird purple blob," says a spokeswoman for the East Bay Regional Park District. "It's native to our area. It's not endangered, but they are rarely seen other than an occasional one here or there." The slugs can reach 15 pounds or more and 30 inches in length, although the ones in the East Bay are smaller—about the size of a large fist or a heart. The boom in sea hares may be related to warmer temperatures near coastal waters, says Morgan Dill, a naturalist at the Crab Cove Visitor Center in Alameda. "We can't say for sure why we're seeing so many, but the Bay temperatures are definitely warmer this year."