Day 228#: Purple-Striped Jellyfish
Today's animal of the day is the Purple-Striped Jellyfish (Chrysaora colorata)!
Photo credit: Pat Webster
Sometimes referred to as the purple-striped sea nettle, this species of jellyfish can be found in the waters off the coast of California from Bodega Bay to San Diego. Their bells (the top part of their bodies) can grow up to 2.3 ft in diameter, and as their name suggests, are covered in purple stripes, though they actually start out pink and slowly turn purple as they age. The exact number, length, and color of their tentacles also change as they age. Juveniles have eight long, maroon colored tentacles along the margin of their bells and then four frilly tentacles in the center of their bells, which are called oral arms. As they age, their tentacles start to become paler and lose their coloration while simultaneously becoming thicker.
Photo credit: Rhododendrites
Like most jellyfish, the purple-striped sea nettle uses its tentacles to sting and capture prey, which mostly includes tiny organisms like zooplankton, copepods, siphonophores, and fish eggs. Once their prey has been stung and paralyzed by their marginal tentacles, they use their frilly oral tentacles to slowly transport it to the jellyfish's gastrovascular cavity, which is simultaneously a mouth, stomach, and anus all in one. The tentacles of the purple-striped jellyfish have been reported to grow up to 15 feet long! Luckily, their stings are non-lethal to humans, though apparently they're incredibly painful.
Photo credit: Steve Lonhart
Young crabs in the genus Cancer often form symbiotic relationships with these jellies, where they will live inside their bells for protection. In exchange, the crabs eat parasitic amphipods that can harm the jelly. In addition to these parasites, purple-striped jellyfish also have to worry about predators like ocean sunfish and leatherback sea turtles, who are immune to their stings and often eat these jellies since their four oral tentacles are especially rich in carbon and nitrogen. Because of this, you'll often find adult specimens who missing these four tentacles after they got munched on by a predator. Luckily, while it does make survival a bit harder for them, they can eventually regrow their missing tentacles after some time has passed.
