You’ve seen it — a blob of jelly goo glistening on the sand. It’s probably not alive, drying in the sun, but you don’t want to touch it. You’re fairly sure it’s a jellyfish and you know jellyfish sting. You’re probably right.
My earlier post — Not all beach blobs are jellies — focused on Melibe, a gelatinous blob that’s not a jellyfish. It’s a non-stinging nudibranch (sea slug). In that post I neglected the real jellyfish blobs on our beaches. This post corrects that omission and shows the jellies (my preferred term for jellyfish) that I encountered as blobs on our beaches in June. Because the blobs don’t do these animals justice, I’ve included links to the lovely living animals, mostly in aquarium exhibits.
This brown blob is a sea nettle (Chrysaora fuscescens). This is the jelly that I see most when I kayak the bay. If you’ve been to the Monterey Bay Aquarium, you probably have pictures of these mesmerizing jellies. The sea nettle grows to 12 inches (30.5 cm) across with 15-foot (4.5-m) trailing tentacles. (By the time jellies hit the sand, tentacles are usually gone.) Sea nettles are stingers and so you don’t want to touch. The stinging cells (nematocysts) can fire even when the jelly is beached. This jelly uses its nematocysts to capture crustaceans, other jellies, fish eggs, fish larvae (baby fish) and other small drifting prey.
This striated jelly blob was new to me and I’ve seen only a few. It’s a crystal jelly, or water jelly (Aequorea spp.). The crystal jelly along our coast grows to about 3 or 4 inches (8 to 10 cm). The striations you see are radial canals, which distribute nutrients from its meals — other soft-bodied animals, mostly jellies. Its sting tends to be mild to people. Researchers working with crystal jellies isolated its light-producing gene, which has led to major glowing-green-in-the-dark, or green fluorescent protein (GFP), research. The GFP work was awarded a Nobel Prize in Chemistry in 2008. Jellies do have value, not only in their environment and as entertainment, but also in helping us understand how life works.
I’m not sure which species this blob is — either a moon jelly (Aurelia sp.) or a purple-striped jelly (Chrysaora colorata), but it has too much purple for the former and not enough for the later (unless it’s a young one). Other distinguishing features aren’t obvious. Moon jellies are a common sight when I kayak. The translucent bell contains whitish oral arms and stomach pouches (except when full of food) and purplish gonads. It can grow to 16 inches (40.5 cm), but the ones I see in the water are usually smaller than 12 inches (30.5 cm). Instead of the long tentacles typical of other jellies, the moon jelly has many fine ones on the bell’s edge and mucus is the weapon it uses to collect tiny zooplankton. These jellies are not powerful stingers, but might irritate your skin if handled. The purple-striped jelly, as the name implies, has purple stripes and some spots. It grows to about 32 inches (81 cm) across with tentacles more than 10 feet (3 m) long. This jelly can deliver a painful sting if handled, so hands off. Like the sea nettle, it eats a variety of zooplankton (drifting animals) such as fish eggs, larvae and other jellies.
These perfectly round little jelly blobs littered my local beach in early June and I couldn’t figure out what they were. At first I thought they were eggs of some kind. They were about the size of a dime. Most were clear; a few had a little something inside. I emailed local jelly expert, David Wrobel, who has a great website, The JelliesZone (my primary source for gelatinous bay life, although any errors in this post are mine, not his). He emailed back that these were most likely sea gooseberries (Pleurobrachia bachei). Although lovely as dots on the beach, the blobs are nothing like the live animals. A sea gooseberry is a type of comb jelly — jellies with running lights. Trailing off the spherical body are two long tentacles with sticky cells (not stinging) for catching little fishes and other drifting prey. Each individual is both male and female (hermaphroditic) and prolific.
During my walks I see these species abandoned on the sand by tides and surf. I love the discoveries, but am saddened by the sights because I know how lovely they are in their watery realm. I hope this’ll give you a better appreciation for the beach blobs you may find on the beach this summer.
For a kayaking view of Monterey Bay jellies, visit my Bestiary.
Note: Don’t handle any sea creature unless you know what it is, what you’re doing and what the regulations are. If you’re stung by a jelly, call 911 and use this WebMD first aid link.
Note 2: After I posted this, rare black jellies were encountered by swimmers off Southern California beaches. Here’s the news with photos.