A quick internet search revealed that they are edible, with caveats. The truth is that Rangia clams are even more plentiful in many of our waterways. The hardy Rangia is the only species of clam that thrives in lower salinity water environments such as the brackish zones common throughout coastal Louisiana.
Ideal conditions for the clam are soft, muddy bottoms in water less than 20 feet deep; in prime areas, they can be as dense as clams per square yard! Rangia clams were dredged throughout the 20th century for use in roadways, parking lots and cement, but by the s, dredging in the lake was banned.
A good fertilization program maintains water clarity between 18 and 24 inches. If Corbicula clears the water of algae, the food chain is broken, and clear water permits weed growth and reduces fish production. This filtering effect is less obvious in unfertilized ponds but could still be an important effect, limiting the food available to the food chain that supports fish production in the pond. The ability to clear the water has been used in aquaculture to reduce the dense algae and bacteria in catfish ponds.
Unfortunately, this has led to further spread of this nuisance species downstream of some aquaculture facilities. Corbicula get into ponds both accidentally and intentionally. Pond owners sometimes add them to a pond with the idea that they will provide forage for the redear sunfish.
Sometimes they are added in a mistaken attempt to improve water quality. This is probably due to their use in aquaculture ponds. Corbicula sometimes enter ponds from sources upstream.
Corbicula produce free-floating larvae that can easily move downstream with the current and then settle. In some cases, they have been introduced to water bodies from bait-bucket dumping; these clams have been used as bait for catfish. Unfortunately, anglers sometimes dump unused and still living bait into the water at the end of the fishing trip. This is a bad idea for any live bait, particularly Corbicula.
Before attempting any control, first determine if Corbicula are present in the pond. Usually there will be some empty shells around the edge of an infested pond. If shells are present, sample the bottom of the pond in a few spots with a shovel or rake.
The Corbicula will be found in the top couple inches of the bottom soils down to a water depth of at least 2 to 3 feet. Control methods are extremely limited for Corbicula. No chemicals are labeled to kill Corbicula that may have become abundant in a pond. There are also no practical biological controls that can be stocked in recreational fishing ponds.
Maintaining high numbers of redear sunfish can help keep the Corbicula thinned to some degree; however, over time, the Corbicula will get out of control because these fish cannot eat the larger clams. Freshwater drum, Aplodinotus grunniens, could be an effective control of Corbicula, but these animals are not available for pond stocking. Catching a few freshwater drum and stocking those into a pond would not provide control; they do not reproduce in ponds. Also, as fish brought in from the wild, they could introduce diseases or even unionid mussels to the pond.
There are fish in Asia that feed on these clams; however, it would be a mistake to bring these animals to North America to try to solve this problem. Besides being illegal, it would compound one mistake with another by introducing another nonnative species that might do further damage to our aquatic resources. The most effective control is periodic partial draining of the pond to lower the water level below the depth where the clams live.
It should be possible to see the depth where the Corbicula stop living by simply scooping up the top 2 to 3 inches of mud and checking for live clams. Exposing the beds for about 2 weeks should kill the clams.
It is not necessary for the exposed pond bottom to dry out completely. As the Corbicula die, their shells open on the surface of the mud, making it easy to determine when the mussels have been killed by the drawdown. Because it is necessary to lower the pond significantly, it should be done in the winter months to reduce the chance of a fish kill. It is unlikely that all Corbicula will be killed; the population will likely start to increase again.
Lowering the water will probably need to be done every few years. If the pond is in an isolated basin not filled by a permanent stream, then a complete draining and restart of the pond might completely eliminate Corbicula. Ponds are systems that rely on algae to support the zooplankton and insects, which are food for the fish. When clams and mussels build up to high numbers in ponds, they can filter out the algae and clear the water, which breaks the food chain and reduces the growth of fish.
If possible, ask locals or tour guides if it is safe to eat the clams in the area. Freshwater mussels are edible, too, but preparation and cooking is required. Locally there are several species one can harvest for dinner. Some North American species are endangered or extinct, many of those surviving are protected. Identify your local freshwater mussels and follow appropriate regulations. Marine mussels taste wonderful in a garlic butter or marinara sauce while freshwater mussels taste like an old dirty shoe.
Dozens of mussel types have already gone extinct in North America, wiped out by water pollution, human development and habitat loss. The current die-off is just one more threat, widespread and fast-moving. Freshwater mussels may be disappearing because their ecosystem or environment where they live is changing. Their ecosystem may be changing in several ways. Pollution Chemicals from factories and garbage that is dumped into the streams and lakes can harm or even kill freshwater mussels.
The mussels have declined by nearly 70 percent because of water pollution and dams, and remaining populations are at high risk of extinction. Freshwater mussels are the most endangered group of organisms in North America because they are highly sensitive to water pollution.
Mussels are an excellent source of protein and leaner than beef, making them beneficial to your diet. When cooked, the shells of the mussels will pop open, making it easy to access the edible meat. Although freshwater mussels are most diverse in North America, where there are species and 16 subspecies, they are among the most rapidly declining animal groups on the continent. Although most natural pearls are found in oysters, they also are found in many different species of freshwater mussels or clams all over the world.
Natural pearls come in a variety of colors.
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