CORPUS CHRISTI, Texas — Tiny shells from millions of marine snails called sea butterflies have washed ashore along stretches of the Texas coast, leaving sharp fragments that beachgoers have mistaken for fiberglass.
Beachgoers reported the debris from Galveston to Mustang Island and Padre Island, prompting some to report feeling tiny, painful pieces sticking to their skin.
Jace Tunnell, director of community engagement at the Harte Research Institute, investigated the reports and found the material came from sea butterflies, also known as pteropods.
“The shells were literally sticking in my fingers like tiny pieces of fiberglass,” Tunnell said.
Sea butterflies are small, free-swimming marine snails that live in the open ocean. Their modified foot acts like wings, allowing them to swim through the water. More than 160 species exist worldwide, with dozens found in the Gulf of Mexico, according to Tunnell.
Their delicate, transparent shells can break into sharp fragments that remain on the sand and can cause painful pokes when people walk or sit on affected areas.
Tunnell counted about 50 sea butterfly shells in a single handful of sand and shells.
Ocean currents, winds and waves can concentrate large numbers of drifting marine organisms along shorelines. Tunnell said changes in ocean conditions, currents or dissolved oxygen levels could have contributed to the unusual concentration along the Texas coast.
Sea butterflies play a role in the marine food web and serve as prey for fish and other marine animals, including some whales.
The sea butterfly buildup comes after another unusual butterfly sighting along the Texas coast. Thousands of American snout butterflies swarmed North Padre Island near Corpus Christi in June after a prolonged drought followed by heavy rainfall.
