An endemic organism is one that is found only within a certain region. There is a rush that goes along with seeing a species that can be found nowhere else. Georgia is actually home to a handful of endemic species, most of which are aquatic. The Altamaha Spinymussel (Elliptio spinosa) is a freshwater mussel only found in 3 river systems in Georgia. Freshwater mussels are actually the most imperiled group of organisms in North America. There are a large number of reasons why this could be but one thing is for sure, mussels are dying in large numbers. To give you an idea of how rare some species can be, when I worked in a mussel lab we would actually pit tag some species so that we would be able to find them later. In the time span of less than a year, our most productive mussel bed had completely died. For the Altamaha spinymuseel, it is estimated that populations have declined 50-70 percent and it only occurred in 7 sites out of 120 sites that were sampled after 2000. Few juveniles or small individuals were found in these surveys. It used to be found in the Ohoopee River system and Oconee River in addition to the Altamaha River system. In the Ohoopee and Oconee, the mussel is thought to be extirpated or populations are so small it is undetectable. All freshwater mussels, expect the Salamander mussel (Simpsonaias ambigua), have a stage in their life-cycle in which they are fish parasites. The glochidia, or baby mussels, attach to fish gills and develop there until they become juveniles. This is how they expand their range.
The Etowah darter (Etheostoma etowahae) is another species that is only found in the Peachtree state. It is a small fish that is about 2 inches long. The fish occurs a less than 10 locations in the Etowah River system. They prefer swift riffle habitats that have either cobble or gravel. There is likely less than 10,000 adults and at sites sampled the darter represents only a small part of the community. Because of this and the expansion of metro Atlanta into its habitat, the species is protected as an endangered species both federally and at the state level. They look very similar to the closely related greenbreast darter (Etheostoma jordani) and lipstick darter (Etheostoma chuckwachatte). Some scientists say that the Etowah darter and greenbreast darter differ by the red markings the Etowah darter has on its sides. This difference between species has been recently challenged with some saying you can’t tell the species apart without genetic testing. The Etowah darter does not co-occur with the lipstick darter so range maps can be used to determine which species you are looking at.