We are learning about the invertebrates found in the Coosa River Basin.
(We have created sketchnotes in our journals. Below are examples of what we have sketchnoted.)
Mastery Quiz 1: Sept 12th - #1-4
Mastery Quiz 2: October 9th- #5, 6, 8, 9
Mastery Quiz 3: October 24th: #7
Coosawattee Crayfish and
Conasauga Blue Burrower Crayfish
Three-horned Wartyback Mussel
- Caddisfly- Aquatic insects that look like a green worm and live in a case attached to rocks. It is intolerant of changes to a stream brought on by pollution. If your stream has caddisflies, that’s an indication that it is a healthy stream.
2. Crayfish-A freshwater crustacean that resembles a lobster, crayfish hide beneath rocks and other debris on the streambed. They feed at night on snails, algae, insect larvae, worms, and tadpoles; some eat vegetation (various water plants). A dead fish worms, corn, and salmon eggs are also favorites of the crayfish. Though they usually move slowly, a flip of the tail can send a crayfish speeding through the water to escape danger.
Coosawattee crayfish is a crayfish found no where else in the world except the Coosawattee River Basin—a headwaters tributary of the Coosa.
Conasauga Blue Burrower Crayfish—this blue crayfish inhabit a system of tunnels that may be very complex with several openings to the surface. Openings to the tunnels are often marked by piles of dirt or mud pellets (chimneys). Depending on the soil type and moisture content, these chimneys can reach heights of 6 inches or more. The Blue Burrower is listed by the State of Georgia as endangered and is known to exist in only one location along the Conasauga River.
3. Earthworms-Working one acre of land, earthworms can create an inch of top soil every five years. Without earthworms, soil becomes compacted, air and water can’t circulate in it, and plant roots can’t penetrate it. Earthworms help water filter through the soil.
4. Interrupted Rocksnail- This rare snail was thought to be extinct until it was discovered in the 1990s on the Oostanaula River. Today, scientists are breeding rocksnails in laboratories and restoring them to portions of the Coosa River Basin. Like mussels, snails are important for clean water. Rocksnails, like mussels, help keep our rivers clean, feeding off algae on rocks. They also become food for a host of other critters such as ducks, fish and turtles. The interrupted rocksnail is now listed as an endangered species.
5. Macro invertebrates - These aquatic organisms lack an internal skeleton and are large enough to be seen with the naked eye. They include mayflies, stoneflies, dragonflies, rat-tailed maggots, scuds, snails, and leeches. These organisms may spend all or part of their lives in water; usually their immature phases (larvae and nymphs) are spent entirely in water. The presence of certain macro invertebrates in a stream can be used to determine the health of a stream.
6. Mayfly - Aquatic insect with feathery gills and a long tail. It is an intolerant species as well. If your stream has mayflies, that’s an indication that it is a healthy stream.
Freshwater Mussels serve as natural filtration systems that help keep the water clean and clear.
Georgia has 98 species of mussels laying its claim to the most diverse mussel fauna of the 50 states. Eleven species of these mussels native to the Coosa basin are currently listed or proposed for listing as endangered or threatened. 13 species are now extinct!
Some of the species that are listed as threatened or endangered are the upland combshell, southern clubshell, finelined pocketbook, triangular kidneyshell, Alabama moccasinshell.
Mussels play an important role in keeping our rivers clean. Because they filter nutrients out of the water, they literally help “clean” our rivers. Our rivers don’t flow as clean as they once did, partly because there are fewer mussels in our rivers.
Washboard Mussel - A common mussel of the Oostanaula River, washboards are large, heavy shelled, multi-ridged mussels that can grow to the size of a dinner plate (12 inches). Its shell is in high demand for the production of cultured pearls.
Spherical pieces of the shell of the washboard mussel are inserted into a host mollusk that then coats the “pearl” with the nacre that turns the former mussel shell into a shining pearl that you’d wear around your neck.
Three-horned Wartyback Mussel - A common mussel found in the Oostanaula and Conasauga rivers. You’ll often found mounds of wartyback mussels at the entrances to otter dens along the banks of the river. They are a favorite food of otters. This mussel gets its name from its thick, heavy shell that has three large humps, or warts, on it. It grows to a size of 2-4 inches in length.
Pistolgrip Mussel - A common mussel found in the Oostanaula and Conasauga rivers. Pistolgrips are easy to identify because of their unique shape. They can be held in the hand much like a pistol. They can grow to be 8 inches in length. Like most mussels, pistolgrips rely on fish to host their “glochidia” (baby mussels). In the case of Pistolgrips, their preferred hosts are catfish.
Corbicula - This non-native species is now the most common mussel found in the Upper Coosa River Basin. It is brown to yellow in color and very small compared with native mussels, growing to more than 1-2 inches in length. It was first introduced to U.S. waters in 1938 in the Columbia River in the Pacific Northwest. Since then, the species has spread to all portions of the US. It reproduces rapidly and unlike native mussels, is very tolerant of different stream conditions. For this reason, it is the only mussel that is found in the mainstem of the Etowah River below Allatoona Dam. Changes to the river ecology as a result of the operation of Allatoona Dam have eliminated all native species from the river. The introduction of corbicula to U.S. rivers has been a blessing and a curse. While corbicula have caused damage to pipes at industrial facilities, they have also replaced native mussels as a food source for other animals as native mussels have succumbed to pollution and other alterations to their habitat.
8. Rat-tailed maggots - These 3/4 inch long whitish larvae are different from other fly maggots in having a 1/2 inch long “tail” that is used as a breathing tube when they are in the water. They thrive in even polluted streams. If your stream has rat-tailed maggots, but no mayflies or caddis flies that might be an indication your stream is polluted.
9. Water penny - Aquatic beetle larvae, this macro invertebrate has a flat saucer body and 6 tiny legs on its underside.