Upper Coosa Biodiversity
North America's Most Biologically Diverse River Basin
Draining more than 5,000 square miles of land, the Upper Coosa River Basin ranges from Southeastern Tennessee and North Central Georgia to Weiss Dam in Northeast Alabama and holds an incredible array of aquatic species.
No other river basin in North America has a higher percentage of endemic species than the Upper Coosa River Basin. Thirty (30) different species of fishes, mussels, snails and crayfishes call the waters of the Coosa—and no where else—home. Researchers call the Upper Coosa Basin a “globally significant biological treasure.”
The Upper Coosa River is the historic home to 100 different fish species, including 12 endemic species. For a river basin in a temperate climate, the Coosa River basin has the greatest number of endemic fish species in the world. This includes six species listed as federally endangered or threatened. Due to the introduction of exotic species, currently, the basin is home to 114 different species.
The basin is also known for its tremendous diversity of mussels and snails. The basin is the historic home to 43 mussel species and 32 species of snails. Sadly, 15 species of mussels and eight species of snails have been lost from the Upper Coosa Basin. In the Upper and Lower Coosa River Basins together, a total of 37 snails and mussels have been lost. Researchers say that this loss is considered the largest single extinction event in U.S. history. Of the mussels and snails remaining in the Upper Coosa River Basin, seven are listed as federally threatened or endangered.
Additionally, the Upper Coosa River Basin is home to 18 species of crayfish.
Threatened and Endangered Species
Federally threatened fish species:
Blue Shiner Cherokee Darter Goldline Darter
Federally endangered fish species:
Etowah Darter Amber Darter Conasauga Logperch
State threatened fish species:
Bluestripe Shiner Holiday (Ellijay) Darter Coldwater Darter
Etowah Darter Cherokee Darter Trispot Darter
Federally threatened mussel species:
Finelined Pocketbook Alabama Moccasinshell
Federally endangered mussel species:
Coosa Moccasinshell Southern Clubshell Southern Pigtoe
Rayed Kidneyshell Georgia Pigtoe
Federally endangered snail species:
Cylindrical Lioplax (extirpated from the Coosa)
Coosa River Fishes:
The Coosa River’s fish population is unique in the variety of minnows and darters found in the water of the basin. These small fish represent over half of the Upper Coosa 114 fish species and all of the endemic and federally listed species. What they lack in size, they make up for in showmanship. Many darters are exceedingly colorful, sporting electric blues, emerald greens and fiery reds.
They generally feed on aquatic insects, though larger species feed on smaller fish and some species eat only plant material.
These fish depend upon flowing, silt-free habitat and high water quality.
Coosa River Mussels:
Freshwater Mussels serve as natural filtration systems that help keep the water clean and clear. They are also a strong “indicator species,” serving as the proverbial canary in a coal mine for our rivers. The loss of five species from the Upper Coosa River and the continuing imperilment of other species, indicates that water quality and habitat for these animals and other aquatic species is poor or declining. Like all mollusks, mussels have a hard shell covering that protects the soft tissues of the animal within. They attach themselves to river bottoms where they lie partially or completely buried, anchored by a single muscular foot. Breathing and feeding are conducted by means of two siphons where water is passed through.
Mussels depend upon fish for reproduction. Fish host the mussel’s larvae which attach to the fish and live there until they develop into juvenile mussels. Mussels can live up to 100 years. They range in size from a quarter to a dinner plate.
Mussels also provide food for some birds, fishes, muskrats, raccoons, otters and other animals. Historically, they were harvested by man and their shells were used for making buttons and other items.
They are dependent upon silt-free, stable river bottoms and high water quality. They are also sensitive to changes in river flows, and the numerous dams on the Coosa and other southern rivers has dramatically reduced suitable habitat for these creatures.
Coosa River Snails:
Like mussels, a snail’s soft tissue is protected by a hard shell which the animal retreats when threatened. This shell grows in a coil around a central column giving most species a distinct spiral shape. Life histories of snails are highly varied but most have separate sexes and reproduce from winter to late spring. Females usually attach eggs to rocks, submerged logs and other firm objects. The eggs hatch in a few weeks and the hatchlings are much smaller that the head of a pin. Most species grow rapidly and are fully mature in on year, with many species living for three to five years. Snails feed by scraping algae and detritus from rocks, vegetation and other firm surfaces.
Freshwater snails are very important ecologically as they help keep our streams clean and healthy and serve as a food source for many other animals. Snails eat so much algae they can often control algal growth thereby positively affecting habitat for other animals. Fishes and crayfish depend upon them as an important food source.
Like mussels, snails depend on stable, low silt environments and many species are sensitive to poor water quality.
Lake Sturgeon Reintroduction:
A holdover from the days of dinosaurs, lake sturgeon are found in the Great Lakes and the Mississsippi River drainage area, and up until the 1960s were found in the Coosa River system. Unfortunately, this unique fish with a shark-like tail, sucker-like mouth and catfish-like barbells under its long snout was driven out of the Coosa River system largely because of overharvesting. In an effort to restore this fish to its original range in the Coosa system, Georgia’s Department of Natural Resources (DNR) began stocking captive raised sturgeon in the Coosawattee, Oostanaula and Etowah rivers in 2002.
Through December 2004, DNR, often with the help of Northwest Georgia elementary school students, had released a total of 32,179 fingerlings. More were released in 2005 and the stocking program is expected to continue an additional 15 to 20 years. Based on reports from anglers, previously stocked sturgeon are adapting well and thriving in the river.
Harvesting lake sturgeon is not currently permitted. DNR asks anglers who accidently catch lake sturgeon to release the fish as soon as possible.
to learn more about the revival of this ancient fish in the waters of the Upper Coosa River Basin.