Moon Jellies are common along the California coast they feed on plankton in quite bays and harbors. They are circular, bell shaped, and translucent with short fine fringe (cilia). They swim horizontally, keeping the bell near the surface. The Moon Jellies sweep up their food with the cilia and store it in pouches until it gets digested by the oral arms. The color of the jelly often changes based on its diet. Although they Moon Jellies sting their prey, the sting poses a small threat to humans.
Scientists have determined that jellies reproduce best when the water has TOO many nutrients and too little oxygen. This unbalanced ecosystem can be common due to the run-off of water from land.
Many organisms depend on the Moon Jellies for food, such as tuna, sunfish, spiny dogfish, all seven species of sea turtles, and birds. Jellies are 90% water, therefore species that are dependent on jellies for food have to eat a lot! Unfortunately, drifting plastic bags look very similar and get mistakenly swallowed. Thousands of birds and turtles die each year from the mistaken
Monterey Bay Aquarium