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Summit to the Sea:
information for k-12 education what is an estuary? | habitat | climate | geology |
hydrology Animals and Plants: Protected Altamaha Spinymussel (Elliptio spinosa) Freshwater mussels live in rivers and streams and sometimes in lakes and ponds. They burrow under the sand and live a few inches below the surface. Once mussels have burrowed under the surface, they don't move very much. Instead of going after their prey, as most other animals do, they filter food from the water. Their prey consists primarily of very tiny animals and plants, known as "plankton", that float in the water. Some tricky steps have to happen for mussels to be able to reproduce successfully. Female mussels produce eggs. In order for the eggs to be fertilized, a male mussel must release his sperm near the female. Then, the female must withdraw the sperm from the water into her shell. Once the eggs are fertilized, the young mussel larvae must attach themselves to a fish! Part of the mussel life cycle includes a harmless parasitic stage. Young mussel larvae must attach to a certain species of fish and go along for a ride for a few weeks. After a few weeks, the young mussels drop off of the fish and settle into the sandy bottom. Finding the right species of fish to attach to is a tricky process, especially since the mussels can't see. Some mussels have special adaptations that they use to attract fish. They display tissue that looks like something a fish would want to eat, that is, they go "fishing."The Altamaha spinymussel is named for its spines. This mussel is very distinctive looking. It is a large mussel, a full handful. It is shiny dark brown, and it has 1-5 spines on both the top and bottom shells.The Altamaha spinymussel is a rare mussel. In fact, it is an endemic species. The Altamaha River watershed is the only place on earth where it lives! Unfortunately, the mussel is in danger of going extinct. Historically, the mussel was found throughout the Altamaha River and in the lower portions of the Ocmulgee, Oconee, and Ohoopee Rivers. Today, it is only found in some portions of the Altamaha and Ocmulgee Rivers. And, the numbers of mussels within these areas have decreased tremendously. One of the worst results from recent spinymussel surveys is that there are almost no juvenile mussels. This means that the populations are not reproducing very much. Many factors may be affecting the spinymussel. Chemical pollution from nearby agriculture, sediment pollution from dredging and development, and disease organism pollution from wastewater treatment facilities may be making the spinymussels sick. Low levels of water during recent droughts concentrate water pollutants and expose sand bars. Humans destroy mussel habitat by riding ATV's on sand bars. Non-native flathead catfish (Pylodictis olivaris) may be reducing the number of native host fish the mussels need for reproduction. Lastly, non-native species may be indirectly harming the mussels. Non-native Asiatic clams (Corbicula leana) may be outcompeting native mussels for food.
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