A female tidewater mucket from the Great Pee Dee – Little Pee Dee confluence. The little “beads” are the marsupium, or reproductive pouches.
The Tidewater Mucket is a freshwater mussel found from Nova Scotia and New England south to the Savannah River. The Mucket is found in tidal freshwater sections of brown water rivers, and can be as large as the palm of one’s hand.
This critter is fast-growing and relatively short-lived as mussels go (8-10 years), but can be very prolific in the right habitats. It is found in shallow quiet waters of major rivers, and will often creep up shallow mud bars to where it is covered by only by an inch or two of water.
The Tidewater Mucket is thin-shelled, relative to other mussel species. This character makes it an attractive food for wildlife, as the shell is easily punctured to access the meat. Even geese will consume them, using one hard peck to punch a hole in the shell, and then pull out the meat.
Virtually all mussels use fish hosts in their reproductive cycle. The Mucket is very versatile here, too, using a variety of catfish, suckers, carp, and bream as hosts.
Despite all its versatilities, this animal is struggling in most of its range. Declines in dissolved oxygen in its habitats is one suspected factor; exotic zebra mussels have seriously reduced its northern populations. The ingress of salt water due to sea level rise is an emerging threat. While it resides in tidal reaches, it has virtually zero salinity tolerance. It does seem to be resilient to sedimentation.
South Carolina has some of the best remaining populations of this animal, with very concentrated populations in the Congaree River, the lower Santee River below Wilson Dam, and in the Great Pee Dee upstream of US701. If you ever see one through a snorkel, it can immediately be distinguished from other mussel species by the brilliant black-and-white harlequin pattern of its mantle (the flesh that shows when the mussel is filtering water, which is almost always).