San Francisco Bay has been invaded these last two weeks by thousands of fat “sea hares” (Aplysia californica). They’re giant, docile, herbivorous sea slugs that eat red marine algae. When disturbed, they expel vivid purple ink in a cloud. We first found them last week at Crab Cove in Alameda, in a long lagoon cut off on the beach by low tide. Later, we found them right here in Lake Merritt. Aplysia are hermaphroditic, and often mate in so-called “Roman circles,” with each one connected to two others, front and behind. They lay millions of microscopic eggs on long strands of yellow string that looks like spaghetti. Each egg strand can be, if uncoiled, a third of a mile long! That can contain 86 million eggs!
It’s always fascinating to find a new species in Lake Merritt.