Jellyfish, Nettles & Other Summer Water Critters

Assateague Island National Seashore is reporting “a lot of weird little blobs of clear jelly washing up on the beach this week; we’re talking THOUSANDS of these things.” writes AINS’s Barry Johnson They look like small jellyfish, but they’re not and don’t sting.

salp (tunicatesea squirt)
Thousands of salp (tunicatesea squirt) have been washing up on oceanside beaches. Barry Johnson with Assateague Island National Seashore says they they are not jellyfish and don’t sting. (Photo courtesy Assateague Island National Seashore)
These are “salps”. They pull water through a tube in their center and filter out microscopic plankton for food. Salps squirt out the filtered water, propelling themselves through the ocean. Officials suspect there was a plankton bloom in the area, causing the salp to get excited and over produce. But they’re dying out as the available plankton is eaten up.
salp (tunicatesea squirt)
Salp (tunicatesea squirt) found in Ocean City & photographed by Karen Heck. Salps are firm but gelatinous. They also have a “primitive eye” that can be seen in this picture. (courtesy Assateague Island National Seashore)
According to some rumors along the beach, these are bluefish eggs. But scientists say those are much bigger (about one inch long) and round — salp are barrel shaped. Also, bluefish eggs have black dots in them (developing embryo).
bluefish egg
Bluefish egg found by a fisherman catching a bluefish.These have a dark spot in the middle. That’s the fish embryo. (Photo courtesy Shawn Kimbro on Tidal Fish.com)
The next question is: what about jelly fish? East Coast sea nettle is a type of jelly fish found in the Chesapeake Bay. Not all jelly fish sting, but the sea nettle does. You want to watch out for it in mid-to-late summer. Right about now, actually.
Sea nettle, a type of jelly fish
Sea nettle is a stinging jellyfish found in the Chesapeake Bay. They show up when the water gets salty and about 68 degrees. (Photo courtesy NOAA)

Sea nettles live in the Chesapeake Bay year round, but they’re in a different shape during winter, spring and early summer and you don’t recognize them or can’t see them. In late summer through early fall, they’ve gotten their bell-shaped top and hair-like tentacles. That’s when they move into the main Bay waters to reproduce. The Bay Journal explains sea nettles it in more detail.

Chesapeake Bay jelly fish
This is the chrysaora quinquecirrha (Cry’-sore-ah kwin-kah-sehr’-ah), the most common sea nettle found in the Chesapeake Bay. They tend to be white in the middle Bay and have red/maroon markings in the southern Bay. And, like many of us, they prefer warm water temps, 78-86 degrees. (Photo courtesy Virginia Institute of Marine Science)

The sting hurts, but is not dangerous for most people. Jelly fish recommendations: just avoid them.

Moon jelly fish are also common in the Chesapeake Bay, but they're harmless to people. They have a wider bell and shorter tentacles. (Photo courtesy the Chesapeake Bay Program)
Moon jelly fish are also common in the Chesapeake Bay, but they’re harmless to people. They have a wider bell and shorter tentacles. (Photo courtesy the Chesapeake Bay Program)
When walking down any beach this time of year, the question is — “Are the jelly fish here yet?” The Chesapeake Bay Operational Forecast System (CBOFS) checks daily to see where they are likely to be. However, it’s not always working. But NOAA created this map to show where they might summer.
Sea nettle (aka jelly fish) chart by NOAA
National Weather Service map of typical sea nettle occurrence in the Chesapeake Bay this time of year. Red is bad. Blue is good. They hang out where the water stays salty and the tide is slower, mainly the tributaries of the middle Bay.

Despite all the hassle, we do kinda want them around. Our Chesapeake Bay sea nettles eat comb jellies. Comb jellies eat fish and oyster larvae. So if we want our summer rockfish and winter oysters, we need to put up with our sea nettles.

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