As is the case with many other states, Georgia has had a plethora of aquatic nuisance species introductions over the years. Though some of these introductions are the result of range expansions or climatic events (e.g. hurricanes, etc.), most of these introductions are result of man-induced activities. Many of these species have the potential to negatively impact native species. In an effort to properly respond to these introductions and formulate appropriate monitoring/management strategies, the Georgia Department of Natural Resources (GA DNR) oversees the management of and response to several aquatic nuisance species that occur in this state.
Moving live fish, aquatic plants, or mussels from one body of water to another can cause irreversible damage to the ecological balance of Georgia lakes, rivers and streams. Releasing unwanted aquarium species or other non-native species may not seem like a big deal, but it can have severe negative impacts on our local fish and fauna. DO NOT RELEASE NON-NATIVE ANIMALS! Should you need help in getting rid of them, contact your regional Georgia DNR Wildlife Resources Division Fisheries Office for assistance.
Stop the spread of aquatic nuisance species. Non-native or introduced species can be an issue in Georgia, often presenting problems for many of our native fish and plant populations. You can help by:
REFRAIN from relocating fish or aquatic plants to areas in which they are not native
REMOVE any non-native species you catch while fishing
REPORT any non-native species you encounter while on the water
REMEMBER to practice CLEAN, DRAIN and DRY after returning to the boat ramp
Report a Non-native Species
It is important that you report any non-native species you may encounter. The preferred method of reporting is to retain the species (preferably alive) in a secure container and contact your regional Georgia DNR Wildlife Resources Division Fisheries Office. Examples of species which should be retained and immediately reported are Northern Snakehead, Giant Salvinia, Zebra Mussel and Asian Carp.
Certain species may be reported online. In doing so, first make sure to take SEVERAL photos of the species, click on the species name below, fill out the subsequent form and submit it online. PLEASE MAKE SURE TO INCLUDE CONTACT INFORMATION (Your name, phone #, etc.) so that GA DNR staff may contact you to learn more about your capture. If you are uncertain about the species you have or the species is not found below, contact your regional Georgia DNR Wildlife Resources Division Fisheries Office.
In early October 2019, an angler captured a northern snakehead in a pond located on private property in Gwinnett County. This is the first time this fish has been confirmed in Georgia waters. It is unknown at this time why the species was released into the private pond from which it was captured, though potential reasons include: released by an aquarium owner who no longer desired the fish as a pet; released during a religious/spiritual event; released after being purchased from a live-fish food market; or released by an angler desiring to establish a new species to target in GA. Regardless, such man-induced releases are illegal and preventable, and such releases can have significant impacts on our native species. Thus, the GA DNR strongly encourages citizens DO NOT RELEASE non-native fish into environments from which they did not originate. Instead, retain the fish and contact your regional Georgia DNR Wildlife Resources Division Fisheries Office.
Aquarium pets are certainly enjoyable to have, and often bring happiness to those who own them. However, sometimes pet owners find themselves unable to care for these animals due to a variety of reasons. In such cases, the owners desire to rid themselves of their aquarium pet may result in the notion that taking the fish to a nearby pond, stream, river, lake, or other outside waterbody and releasing it is a good way to dispose of the animal. However, such actions can potentially have dramatically negative consequences on our native species in those waterbodies. Therefore, DO NOT RELEASE animals into a body of water from which they did not originate! Instead, you are encouraged to contact the pet store from where you purchased the animal and see if the animal may be returned to them. Otherwise, please contact your regional Georgia DNR Wildlife Resources Division Fisheries Office for assistance on how you can properly dispose of the animal(s).
In October 2019, the first northern snakehead in GA was captured and reported by an angler in Gwinnett County. This is the first time this fish has been confirmed in Georgia waters. Native to China, Russia, and Korea, Northern snakeheads have been imported in several countries, including the USA, primarily for food purposes. An obligate air breather, the species can live out of water for hours and can travel short distances across land. As an apex predator, the species has the potential to have negative impacts on native species in areas where it is introduced. In Georgia, it is unlawful to import, transport, sell, transfer, or possess any species of snakehead fish without a valid wild animal license. If you suspect you have found a snakehead:
- DO NOT RELEASE IT.
- Retain the fish in a secure container from which it cannot escape.
- If possible, take pictures of the fish, including close ups of its mouth, fins and tail.
- Note where it was caught (waterbody, landmarks or GPS coordinates).
- IMMEDIATELY report it to your regional Georgia DNR Wildlife Resources Division Fisheries Office.
Of all aquatic nuisance plants in Georgia, perhaps none poses a greater threat than giant salvinia (Salvinia molesta). This invasive plant is one of the world’s most noxious aquatic weeds and is notorious for dominating slow-moving or quiet freshwaters. Found in Georgia since 1999, it grows rapidly and forms free-floating colonies that create thick mats, which lead to oxygen depletion and absence of light for native vegetation. Sometimes confused with the native common salvinia, giant salvinia can be distinguished through examination of the stiff hairs on top of its leaf that branch into 4 parts which reconnect at the tip forming an “egg beater” appearance (leaf hairs on common salvinia do not reconnect). Infestations of this species can result in complete blockage of waterways, irrigation and power generation intakes. Control of the species can be achieved through multiple avenues: Biological (Salvinia weevil, Cyrotobagus salviniae); Mechanical Removal; Water Level Drawdown; and Chemical (herbicides). IF YOU SUSPECT YOU MAY HAVE GIANT SALVINIA IN YOUR WATERBODY, IMMEDIATELY contact your regional Georgia DNR Wildlife Resources Division Fisheries Office.
Native only to the Coosa River in Georgia, flathead catfish (Pylodictis olivaris) have decimated the popular redbreast sunfish and bullhead fisheries in the Altamaha River since their introduction in the mid-1970s. In the mid-1990s, the species was also illegally introduced into the Satilla River, a river known historically for its redbreast sunfish fishery. Flatheads pose a direct threat to these sunfish and many other native panfish. As such, GA DNR staff have dedicated significant time each year since 2007 to removing flathead catfish from the Satilla River in an effort to suppress the population and minimize its impacts on native fish populations.
One of the largest freshwater catfish species in North America, blue catfish (Ictalurus furcatus) are native in Georgia only to the Coosa River but have been introduced into several locales throughout the state. Several rivers (Ocmulgee, Oconee, Altamaha, and Satilla to name a few) are now home to the species, and concerns exist as to the potential impacts the species may have on native fish. Highly omnivorous, the species has been found to prey on non-native Asian clam (Corbiucula fluminea) in the Satilla River (and other rivers) while also feeding on a multitude of native fish. As part of the flathead removal project on the Satilla River, GADNR staff are removing non-native blue catfish as well.
Asian Swamp Eel
Having been found in multiple locations in Georgia but actually native to Asia, India, and China, the Asian swamp eel (Monopterus albus) is not a true eel. The species has a scaleless, elongated body with a tapering tail and blunt snout, unlike the native American eel (Anguilla rostrata) that has embedded scales; pectoral fins; and rayed dorsal, anal and caudal fins. The life cycle of the Asian swamp eel, which occurs entirely in freshwater, is quite interesting: all young are female at birth, with some changing into males as adults, though such males may transition back into females should female densities become low. Such strategies, along with the species ability to exists in a variety of habitats (shallow wetlands, stagnant waters, marshes, streams, rivers, ditches, canals, lakes, reservoirs, and shallow ponds); it’s tolerance of cold temperatures (can survive below freezing); and it’s tolerance of a wide range of water oxygen levels make it a very adaptable non-native species. The ecological impacts of Asian swamp eels remain relatively unknown, but the potential for the species to negatively impact native species through predation or competition is concerning.
Hydrilla (Hydrilla verticillata) is an aquatic plant species that is native to Eurasia and was believed to have been first introduced into the US in the 1960s. It is also known as Florida elodea, water thyme, water-thyme, and waterthyme. This plant is present in several Georgia waterbodies around the state. Research has recently been done to investigate potential links between hydrilla infestations and outbreaks of an often fatal disease that can affect birds. Most recently, a link to hydrilla has been suspected in bald eagle deaths in the Southeastern US.
Island Apple Snail
Island Apple Snail (Pomacea insularum) are originally native to South America. These exotic snails have been found in Georgia, California, Florida, North Carolina and Texas. The shells can be near baseball-sized (80 mm or over 3 inches). The large egg masses are laid on vegetation or trees and are bright pink or orange in color. Egg masses can be 2 to 3 inches long and may contain 200–600 eggs.
Aquarium Fish Species (Pacu, Tilapia, Oscar, Haplo, etc.)
Over the years, several species of aquarium fish have been found in private and public waters in Georgia. These introductions typically occur as a result of aquarium owners who no longer wish to keep these pets decide to release such species into local waters. Unfortunately, these decisions can have dramatically negative impacts on native species populations. Consequently, we urge aquarium owners DO NOT RELEASE NON-NATIVE FISH/PETS that you no longer wish to keep or are able to keep. Instead, contact your regional Georgia DNR Wildlife Resources Division Fisheries Office for assistance on how to properly dispose of the animal(s). Should you encounter any of these fish while fishing in public or private waterbodies, contact your regional Georgia DNR Wildlife Resources Division Fisheries Office.
Native to Indo-Pacific, Asian, and Australian waters, Asian tiger shrimp (Penaeus monodon) are now found along the southeast and Gulf coasts of the United States, including Georgia. While small numbers of this non-native species have been reported in U.S. waters for over a decade, sightings have increased over the past few years. Tiger shrimp are one of the primary species raised in shrimp farms around the world and can grow to be three times the size of our native shrimp. Able to grow 2x or more the size of native white or brown shrimp, tiger shrimp are of concern due their potential to compete for food and habitat resources, prey on native shrimp, and potentially transmit disease to our native shrimp populations. In an effort to better track captures of tiger shrimp along Georgia’s coast, the GA DNR is requesting fishermen who capture any of the species to help provide some much needed data on such captures.
The northward expansion of the lionfish (Pterois miles) population in the past 2 decades since its first sighting in the Atlantic off the Florida coast in 1985 has undoubtedly created much angst amongst fishery managers. A notorious top-level predator, lionfish have been known and found to consume significant quantities of other reef fish, including prized grouper and snapper species. Such predation has been shown to negatively impact both the quantity and characterization of these and other fish sharing habitats with lionfish.
An anadromous species native along much of the Atlantic coast, including Georgia, blueback herring (Alosa aestivalis) have been introduced in several inland waterbodies. Similar to alewife (Alosa pseudoharengus), blueback herring are dorsally blue and have 44–50 rakers on the lower limb of the 1st gill arch, while alewife have 39–41 and are green dorsally. A voracious consumer of zooplankton and fish eggs/fry, blueback herring have negatively impacted sunfish (bream), largemouth bass, white bass, walleye, and crappie populations in several of the Georgia mountain lakes where they have been illegally introduced.
Native throughout much of the Atlantic coast north of Georgia, alewife (Alosa pseudoharengus) have been introduced in several inland waterbodies, including Lake Carters and Allatoona, Coosa River, and Savannah River. Similar to blueback herring (Alosa aestivalis), alewife are dorsally green and have 39–41 rakers on the lower limb of the 1st gill arch, while blueback herring have 44–50 and are blue dorsally. Like blueback herring, this voracious consumer of zooplankton can negatively impact and alter food webs, causing significant impact to native fish populations, including white bass populations.
Alabama bass (Micropterus henshalli), better known as Alabama spotted bass, were once considered a subspecies of spotted bass, but as of 2013 are recognized as a separate species more closely related to the red-eye basses. Native to the Coosa and Tallapoosa rivers in Georgia, the popularity of the species fast growth resulted in illegal introduction of the species throughout many other large waterbodies in Georgia, including Lake Lanier in the early 1970s. While the species has an ability to grow faster and larger than spotted bass, the species poses a significant concern in introduced areas and has proven to hybridize with every native species of black bass in the state except Suwannee bass. Such hybridization is problematic and compromises the genetic purity of native bass species like shoal, Chattahoochee, smallmouth, and largemouth bass. Not only have largemouth populations been affected by the species, but Georgia's best smallmouth bass fishery, Lake Chatuge, was lost to illegally-stocked Alabama bass. The only remaining smallmouth bass fishery, Lake Blue Ridge, is also threatened by Alabama bass competition.
While Alabama bass may be more aggressive and thus catchable for some fishermen, they are not native to much of Georgia and can have negative impacts on other fish species. Consequently, anglers should not relocate or introduce either of these species into new areas.
Spotted bass (Micropterus punctulatus), also known as Kentucky spotted bass, are native to the Mississippi River and Gulf drainages, including the Tennessee River and waters just inside the north Georgia border. While the species is not native to most of Georgia, it has been introduced into various waterbodies in Georgia in recent years. The negative implications of the fish in changing the dynamics of an ecosystem (lake, river) and affecting native bass populations through competition and cross-breeding present difficulties for fishery managers.
While spotted bass may seem desirable to some fishermen, they are not native to much of Georgia and can have negative impacts on other fish species. Consequently, anglers should not relocate or introduce the species into new areas.
Yellow bass (Morone mississipiens) are native to the Mississippi and Tennessee River drainages, including some waters in the upper northwest corner of Georgia. This smaller Morone species has been introduced into other locales in Georgia, including the Coosa (Etowah and Oostanaula rivers, Rocky Mountain PFA, and Carter’s Lake). In areas where it is not native, the species has the potential to compete with other more desirable game fish. Adult size is relatively small compared to other Morone species, making them less desirable to some anglers. There is no size or creel limit on yellow bass, and anglers are encouraged to harvest the species.
Other Invasive/Non-native Concerns in Georgia
Georgia trout populations are threatened by the following newly occurring invasive diseases:
- Whirling Disease: First detected in the U.S. in 1958, this disease is found in more than 20 states, including in the Watauga River in North Carolina in 2015. Whirling disease can cause 90 percent or greater mortality of young rainbow trout and can have serious impacts to wild and hatchery trout populations. The disease is caused by the microscopic parasite Myxobolus cerebralis, which damages cartilage and skeletal tissue in trout causing diseased fish to swim in a "whirling" motion. While often fatal to juvenile trout, the disease is not known to affect humans or pets, and eating an infected fish is not known to cause any harmful effects. How to prevent the spread of whirling disease.
- Didymo: This disease, also called rock snot, is a freshwater diatom that produces thick algae mats along stream bottoms. The mats can be so thick that they can alter stream habitats and make fishing difficult. Didymo can be spread easily from one water body to another. This microscopic algae was recently found in North Carolina for the first time and is a threat to Georgia streams and rivers. How to prevent the spread of Didymo.
The following parasites are known to potentially be problematic for various fish species in Georgia:
- Gill lice: These lice, a parasitic crustacean that attach to the gills of trout, recently were found in trout in North Carolina. In high concentrations, these lice can impact respiration and the health and survival of the trout.
- Achtheres: A parasitic copepod that infects the gills of freshwater fish, especially striped bass, and is easily visible when it matures and moves into the fish’s mouth and gill arches. First documented in Tennessee, the parasite has been observed in several Georgia lakes. Though currently not believed to cause direct mortality, it is believed to cause some fish stress and, along with other factors, could impact fish health. Read more information on Achtheres.
Examples Near Our State
Native to freshwaters in Eurasia, the zebra mussel (Dreissena polymorpha) was introduced in the Great Lakes in the mid-1980s, likely via ballast water. Since then, the species has been moving south, and is now found in Tennessee and Alabama. Though not currently known to exist in Georgia, the potential for the species to find its way here is very real. Distinguished by the striped pattern on its shell, zebra mussels are small in size (<2”) but potentially very large in impact. The species has the potential to cause significant ecological (adversely impact Georgia's native mussels, many of which are endangered) and economical (completely clog intakes for drinking water, power plants and outboard motors, costing millions of dollars in damage, control and abatement) impacts. Consequently, it is imperative boaters and other users visiting nearby areas having these invasive species take necessary precautions to prevent bringing them into Georgia. If you suspect you’ve found a zebra mussel, retain it and immediately contact your regional Georgia DNR Wildlife Resources Division Fisheries Office. Be sure to note where you found the specimen(s).
Imported to the U.S. in the 1970s as a means of controlling algal blooms in aquaculture ponds and wastewater treatment facilities, Asian Carp (both Bighead and Silver) are exotic fish species invading and causing harm to native fishes and mussels throughout the Mississippi River basin. A fast-growing filter feeder, the species can dominate a fish community; impact native species; alter water quality; harm important commercial and recreational fisheries; and create a significant safety hazard for boaters. As has been seen on many occasions, some species of Asian carp (e.g. Silver carp) have a tendency to jump when scared, thus creating a significant hazard to people operating boats, who may be injured by fish landing in their boat. Native to China and prized there for aquaculture, the species is now found as far south as the Tennessee River basin, which falls (in part) in north Georgia. Though the species has not been detected in Georgia waters yet, it’s close proximity is of serious concern. If you suspect you have captured an Asian carp, retain the fish and immediately contact your regional Georgia DNR Wildlife Resources Division Fisheries Office. Be sure to note the location of where you found the specimen(s).
You Can Help Prevent the Movement of ANS
- Never release live bait, aquarium fish, aquatic plants or mussels into Georgia waters, and properly dispose of bait. For more information on disposing of unwanted fish, plants, or other biota, contact your regional Georgia DNR Wildlife Resources Division Fisheries Office.
- ONLY GA DNR staff is authorized to stock or move live fish or aquatic plants from one body of water to another.
Georgia boaters and anglers can help prevent the movement of aquatic nuisance species through these simple actions:
- CLEAN gear, watercraft, trailer, motor, and equipment. REMOVE visible aquatic plants, mussels, other animals, and mud before leaving any water access.
- DRAIN water from gear, boat, bilge, motor and livewell by removing drain plug and opening all water draining devices away from the boat ramp. NEVER empty your bait bucket into Georgia waters.
- DRY everything at least five (5) days before going to other waters and landings or SPRAY/RINSE recreation equipment with high pressure and/or hot water (120 degrees F/50 degrees C or higher).
- CLEAN gear and recreation equipment. REMOVE visible aquatic plants, mussels, other animals, and mud before leaving any water access.
- DRAIN water from gear and equipment, but NEVER empty your bait bucket into Georgia waters.
- DRY everything at least five (5) days before going to other waters and landings or SPRAY/RINSE recreation equipment with high pressure and/or hot water (120 degrees F/50 degrees C or higher).
By taking these simple actions, you can help the Georgia Department of Natural Resources' Wildlife Resources Division protect Georgia's native aquatic resources and ensure good fishing for future generations.
For more information about aquatic nuisance species and ways that you can protect Georgia waters, visit the Stop Aquatic Hitchhikers program website or Facebook page. The Georgia Department of Natural Resources is a cooperating partner in this program.
Thank you for protecting your Georgia waters, your native fish and wildlife populations, and your excellent sport fishing opportunities across this state.
Georgia is working to educate and inform citizens of the threat of Aquatic Nuisance Species (ANS) and how we can best combat them in multiple ways. These include the development and implementation of management plans and projects; partnerships with other agencies; and ongoing education and outreach events.
Plans & Projects
- US Fish and Wildlife Service
- Gulf and South Atlantic Regional Panel
- Coastal Georgia CISMA
- US Geological Survey
Each year, GA DNR staff speak to hundreds of kids at various schools in our state. These events provide an excellent opportunity for students, teachers, and parents to hear about invasive species issues in our state, learn about many of our native species, and discover how they can help us in our efforts to prevent future introductions of non-native species. If you are interested in having someone speak to your school or civic group about native or non-native species in Georgia, please contact the GA DNR Fisheries office in Waycross at 912-285-6094.