The invasive Thrush Cowrie (Naria turdus) has been found off Panama City Beach, in the Florida Panhandle. In early July, diver and shell enthusiast Doug Thompson was diving inside a shipwreck located at a depth of 24 m (about 78’), when he found a “fresh dead” Thrush Cowrie shell. Doug reported that other divers had found the species living in the same area and off Destin, also in the Panhandle.
Originally from the Red Sea and western Indian Ocean, the tenacious invasive was first reported in the Mediterranean Sea sometime in the last couple of decades, and from there to the lower Caribbean in May 2022. In March 2023, we reported the first discovery of the species in the US (Lake Worth Lagoon, Florida). Since then, the species has been found by divers and beachcombers in and off Miami-Dade, Broward, and Palm Beach counties along Florida’s east coast and also in the Florida Keys.
The new records were found approximately 800 km (about 500 miles) from the closest location where the species was previously collected, Key West in the Florida Keys. How does the species migrate such large distances? Cowries have open-water larval stages, and their larvae may get transported via currents to distant locations, or in the bilge water of ships and smaller vessels. Is the species likely to be found living as adults in intermediary locations off the west coast of Florida? The saga of the Thrush Cowrie will continue!
If the species is invasive, like the thrush cowrie, is it OK to take live ones?
Please note that planktonic larvae may persist in ballast water, which is regularly exchanged on modern seagoing vessels. Bilge water is not and it is not a source of unwanted larvae of nonindigenous species.