The bell of a Pacific Sea Nettle holds the tools it needs for navigation. It contains muscles that contract and expand, creating a backward thrust and an outward jet of water that facilitate movement. Light-sensing “eye spots” help differentiate light and dark, while statocysts—sensory structures—maintain the sea nettle’s orientation as they drift through water.

Pacific Sea Nettles use their exceptionally long tentacles to catch prey. Their stinging tentacles are lined with stinging cells that inject a toxin to stun their prey, which are then moved to the mouth by their oral arms. As they search for food, Pacific Sea Nettles move up and down through the water, sometimes travelling over 1 km in a day to follow prey that migrate with changing light.

An important part of the food web, this species is a crucial food source for marine animals like sea turtles. But plastic pollution puts these predators at risk. Floating plastic bags can look like sea jellies and may be swallowed by mistake, leading to serious or even fatal health problems.