Moon jellyfish (Aurelia aurita) can be found throughout the oceans of the world, and are one of the more common types of local jellyfish. In fact, in previous years, many moon jellies have washed up on Humboldt beaches.
They can be identified by four horseshoe shaped gonads at the top of the bell. Jellyfish are 95% water and have no brain, blood, or heart. They feed by collecting medusae, plankton, and mollusks with their tentacles, and bringing them into their body for digestion.
They reproduce with a mixture of sexual and asexual reproduction–young jellies, known as polyps can create buds that grow into new polyps. Moon jellies aren’t in much danger from humans, however their pretadors, such as birds and turtles, often ingest plastic bags after mistaking them for jellies.
Sources: Moon jelly–Monterey Bay Aquarium; Moon Jelly–Wildlife Trusts; Aurelia aurita–Wikipedia. Photos: Matt Evans and Ann-Sophie Qvarnström on Flickr