It looks like a mop tangled in seaweed.
When a bizarre, white-polka-dotted blob the size of a person’s palm washed ashore in North Carolina last December, rangers at Cape Lookout National Seashore weren’t sure what to make of it.
So the rangers turned to the public for identification help, posting a photo of the semitranslucent blob tangled in seaweed on their Facebook page on May 18. “It might be something like the egg sacks of a squid (but we aren’t sure),” Cape Lookout rangers wrote in the post.
Turns out, their guess was spot-on: The blob is likely made up of the eggs of the Atlantic brief squid (Lolliguncula brevis), two biologists told Live Science. This squid, which lives in inlets and estuaries along parts of the Atlantic coasts of North and South America, is so small, it’s “not the target of commercial fisheries, but they are abundant and important in marine ecosystems,” said Ian Bartol, a professor in the Department of Biological Sciences at Old Dominion University in Virginia who was not involved with the blob’s discovery.
The blob’s odd shape is officially known as an egg mass, but it has so many egg-filled sacks, researchers sometimes call such masses “mops,” said Michael Vecchione, an invertebrate zoologist at the Smithsonian’s National Museum of Natural History in Washington, D.C., who was not involved with the recently discovered blob.
After mating, female brief squid lay about 30 eggs in a clear, gelatinous finger-shaped sack, which is usually about 1 inch (2.5 centimeters) long, Vecchione said. Then, the female secures the egg-filled sack to the seafloor in shallow waters — for instance, to oyster shells or clam shells — and other females often follow suit, attaching their egg-filled capsules to the same base, forming a mop.
It’s unclear why females attach their egg capsules together, but the strategy might be protective. “If one capsule is attached and it doesn’t drift away, chances are, that’s a good place to attach them,” Vecchione told.
In the Chesapeake Bay, brief squid usually lay their eggs in September and October, Vecchione said. Farther south, the squid might lay their eggs later in the year, “so finding them in December in North Carolina doesn’t really surprise me,” he said.
It’s possible that strong currents from a storm washed the egg mass ashore on Shackleford Banks, one of the barrier islands in Cape Lookout National Seashore, where they were found on Dec. 31, 2020, Karen Duggan, a park ranger at Cape Lookout National Seashore.
While getting washed ashore was definitely a game-ender for these eggs, there are surprisingly few predators that eat these mops in the ocean, Vecchione noted. For instance, some worms burrow into brief squid egg capsules, and in other squid species, crabs and fishes prey on egg masses, “but it’s not very common,” Vecchione said. “If they were easy to eat, then they would just be a smorgasbord for whoever comes along.” It’s possible that the gelatinous capsule has chemical defenses, and there’s some evidence it has anti-microbial properties, he added.
After the squid babies hatch from their eggs, however, it’s another story. “As soon as they start hatching, they’re fair game for a lot of things,” including fish and other marine animals that eat plankton-size prey, Vecchione said.
In adulthood, a brief squid’s mantle (a measurement that doesn’t include its head, eight arms or two tentacles) is usually no larger than 4.7 inches (12 cm) long, according to the South Carolina Department of Natural Resources. The squid has a few claims to fame. For one, it can live in waters with low salinity — as low as half that of regular seawater — which is rare among cephalopods, a group that includes squids, octopuses and nautiluses, Vecchione said. The brief squid can also tolerate “a broad range of temperatures and dissolved oxygen levels, allowing it to venture into estuaries where other squids cannot,” Bartol added.
Brief squid also have rotating jets, so they can easily “swim both forward (arms first) and backward (tail first), and they are extremely maneuverable, as the jet and fins can be employed in a coordinated fashion,” Bartol said. They can also change color, achieving optimal camouflage, he said.
A DNA analysis would be needed to formally identify this egg mop, as it is “kind of beat up from being washed ashore,” but based on its size and place of discovery, it most likely belongs to a brief squid, Vecchione said. Other guesses include the longfin inshore squid (Doryteuthis pealeii) and the slender inshore squid (Doryteuthis plei), which also live in the region, according to an update Thursday (May 20) on the ranger’s Facebook post.