Trout
Photo: wildsouth.org
Brook trout, Salvelinus fontinalis, historically ranged from Southern Canada to North Georgia, but they are now stocked elsewhere in the U.S. and around the world. The genetically distinct Southern Appalachian Brook Trout (SABT) are found specifically in the Southern Appalachians, including the Chattooga River watershed. Brook Trout are widely known for their colorful markings, often distinguished by the olive-green coloration of the upper sides with mottled, dark green “worm-like” markings on their backs and tails, which has earned them the name “specks” by many locals. Male Brook Trout display especially vibrant colors during mating season (fall) to attract females.
What environmental conditions do SABT require?
Most Brook Trout in the Chattooga watershed are located in our smaller headwaters due to temperature constraints, headwaters isolation, and non-native fish species competition. They require cold, clear, unpolluted, and well-oxygenated water, and do especially well in rivers with consistent water flow, adequate stream cover, and river bottoms free of excessive sediment to provide gravel for spawning. Brook Trout feed on a variety of aquatic and terrestrial insects, and occasionally crustaceans, small fish, and other vertebrates.
How has the history of the Chattooga Watershed impacted our Brook Trout populations?
During the late 19th and early 20th century, detrimental land use practices greatly impaired the waters and aquatic habitats of the Southeastern U.S., including the Chattooga watershed. Vast stands of virgin timber were harvested on steep slopes of the watershed, splash dams were created to transport logs downstream, and miles of roads and rail lines were constructed up the river valleys. These poorly planned activities resulted in extensive erosion and siltation, which degraded water conditions and severely reduced the watershed’s SABT populations. This decrease in native SABT resulted in the stocking of non-native Rainbow Trout (Oncorhynchus mykiss) from the Western U.S., Brown Trout (Salmo trutta) from Europe, and northern strain Brook Trout to supplement sport fishing. Today, these non-native species continue to dominate and out-compete the sensitive native Brook Trout.
Explore the sections below to learn more about threats to Brook Trout populations in the Chattooga River watershed and Southern Appalachians, and what can be done to help.
Riparian Areas and Decline of Hemlock
Riparian areas are the strip of land bordering a body of water, such as a stream, river, or lake. With plenty of access to water, this typically has a lush dense belt of vegetation.
Healthy, vegetated riparian areas are important for aquatic life because they act as a buffer to all the activities that occur on the land. They act as a filter, helping to catch and reduce sedimentation flowing into streams, and they stabilize the soil at the water’s edge and prevent bank erosion. Intact riparian areas also shade the stream and help keep water temperature cooler. When riparian areas that provide shade are removed from beside cold-water streams, this can increase the water temperature by upwards of 10ºF in these sections.
According to Coats and Jackson (2019), “riparian restoration may be a key to mitigating climate change effects on streams.”
Hemlocks are large coniferous evergreen trees. They are known to be slow-growing and, unlike many trees, grow well in shade. The Eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) are found in the Chattooga watershed. Commonly found near rivers and streams, especially in mountain cove communities, hemlocks are very important riparian shade trees. These trees are unrelated to the invasive, highly poisonous flowering plant, Poison hemlock (Conium maculatum).
Carolina hemlock (Tsuga caroliniana) is only found in the Southern Appalachian mountains and is found in the Chattooga watershed on cliffs, rocky slopes, and ridges at elevations greater than approximately 3000 ft. Eastern hemlock (Tsuga canadensis) is more widely distributed, occurring in most of Eastern North America. In the Chattooga watershed, Eastern hemlock is found on north and east slopes, in coves, or in cool moist valleys typically above 1800 ft in elevation.
The hemlock woolly adelgid (Adelges tsugae) is a non-native invasive insect that feeds on the sap and stored nutrients of hemlock tree species. This exotic species was accidentally introduced in the 1950s from Asia. In the course of feeding, they cover themselves with a white secretion giving infected trees the appearance of “cotton balls” on the underside of their leaves. In most cases, untreated infestation leads to the eventual death of the hemlock tree.
Faulkenberry, Hedden, & Culin (2009) state that “The loss of hemlock, and its replacement by hardwood species, is likely to significantly affect stream habitats, lowering invertebrate diversity and altering the trophic structure of fish and invertebrates, as well as nitrogen and other nutrient fluxes from the canopy to the forest floor (Snyder et al. 2005, Stadler et al. 2006).”
Climate Change
The term “climate change” generically refers to long-term shifts in temperature and weather patterns across geologic time. In recent times, the term “greenhouse effect” or “anthropogenic (human-induced) climate change” has been used to represent the rapid rise in global temperatures since the Industrial Revolution due to human–produced overabundance of greenhouse gases such as carbon dioxide.
Global temperatures have fluctuated throughout the Earth’s history. Over the last 800,000 years alone, there have been eight cycles of ice ages and warm periods. Our current rate of warming due to human-induced activities is creating warming at a rate not seen in the past 10,000 years and is well beyond that of natural variations in climate.
Early on, it is believed that Brook Trout were only found in the areas from roughly New Jersey to the Hudson Bay area of Canada. As glaciers advanced and retreated due to global temperature changes, the Brook Trout were aided in finding a new home in the Southern Appalachians. This arrival is thought to have occurred sometime during the Pleistocene Epoch, from 1.8 million years ago to 11,000 years ago.
The Chattooga watershed represents the southern limit of the natural range of Brook Trout in eastern North America. As modern climate change progresses, SABT on the edge of their range continue to have temperature tolerances pushed to critical limits. As average air temperatures rise, so do water temperatures. Brook Trout start to become stressed at 65ºF and cannot survive as temperatures near and exceed 70ºF.
Flebbe, Roghair, and Bruggink (2006) estimate that “future loss of cold-water fish habitat could be from 53-97% in the southern Appalachians due to increased stream temperatures in a warmer climate.” Mitigating for climate change is one strategy to help ensure our rivers and streams are cold enough for SABT survival.
Non-Native Competition
The Chattooga watershed currently has three trout species that occupy its waters: our native Southern Appalachian Brook Trout (Salvelinus fontinalis), the non-native Rainbow Trout (Oncorhynchus mykiss) introduced from the Western U.S., and the non-native Brown Trout (Salmo trutta) brought over from Europe.
Brook Trout:
Known for their distinctive color pattern, the adults are greenish with impressed lines or worm-like vermiculations on the back, top of head, and dorsal fin, while the sides are speckled with bright yellow spots mixed with brilliant red spots on sky-blue halos. The olive-green background grades to bright yellow followed by brilliant red on the belly of the fish. All of the bright red ventral fins have a distinctive white stripe along the leading edge margined with black, typical of the Salvelinus genus.
Rainbow Trout:
A beautiful fish, the Rainbow’s name refers to its colorful pinkish-red band, which extends from its gill plate along its sides. Numerous blackish or brownish spots mark the back as well as the dorsal, adipose, and caudal (tail) fin. These spots are better developed on the tail fin in this species than on the Brown Trout. Spots on Rainbow Trout are generally small and very numerous, unlike Brown Trout which have larger less numerous spots.
Brown Trout:
The Brown and the Rainbow share some common characteristics in behavior, habitat and appearance but can still be easily identified as separate species. Adults of the Brown Trout may be distinguished from the Rainbow by the absence of a reddish band along the sides, the presence of orange or reddish spots, sometimes with green margins, and the weak development or absence of dark spots on the tail fin.
(SC Trout Species – South Carolina Department of Natural Resources website)
Knowing traits and adaptations of each species of trout that currently inhabits the Chattooga watershed can help us understand why competition trends exist.
Brown Trout typically inhabit lower gradient streams with lots of pools and can tolerate more turbid silty conditions with warmer stream temperatures. These are aggressive fish that generally out-perform the other two species when competition is heavy. They, like the other trout species, feed heavily on insects but are also more likely to utilize fish, crayfish, and salamanders as well.
SABT are the most sensitive to both turbidity and cold water temperature out of the three species. SABT grow slowly, especially in the smaller headwater environments they are mostly restricted to in the Chattooga watershed. The other trout species thus become larger and more dominant sooner, often outcompeting SABT for habitat and resources.
Rainbow Trout fill the space in the middle between the two extremes of the other trout species in the watershed in almost all categories of competition.
Huntsman, Merriam, Rota, & Petty (2023) state that “Brown and rainbow trout negatively affect brook trout populations through competition for optimal habitats (e.g. foraging and hydraulic) and thermal refugia—a process that will become increasingly detrimental to brook trout as streams continue to warm (Fausch & White 1981; Fausch 2008; Hitt et al. 2017).”
Isolation in the Headwaters
Headwaters are the small streams at the start of a watershed that flow together to form progressively larger and larger rivers.
SABT, as our only native trout species, have lived in the headwaters for at least the last 10,000 years. Historically, before detrimental land use practices and the resultant stocking of other non-native trout species, SABT occupied the entire Chattooga watershed in large numbers.
SABT are isolated in the headwaters of the Chattooga watershed due to competition by the often more aggressive non-native Rainbow and Brown Trout, as well as water quality conditions. SABT are very sensitive to water degradation and temperature fluctuations, so sedimentation and increased water temperatures exclude many SABT populations from larger downstream river sections and tributaries.
Isolation of SABT into small, disconnected populations can increase the risk of extinction of local populations. Lack of genetic diversity and gene inflow due to inbreeding can lead to genetic problems as well as reduced resiliency to environmental changes and disease. That is why the ability to maintain a large enough population with adequate connectivity is critical when balancing the advantages and disadvantages of environmental circumstances and management to SABT populations.
Unfortunately, options are limited to prevent isolation of SABT in the Chattooga headwaters. The majority of the watershed is stocked with non-native trout species that typically outcompete SABT for access to larger bodies of water. With rising temperatures due to clearing of riparian areas, decline of hemlock species, and the continuing impacts of climate change, the SABT will be further restricted to headwaters areas due to increasing water temperatures. However, efforts by organizations such as the U.S. Forest Service and Trout Unlimited to replace road culverts and remove other fish barriers are allowing for some SABT populations to be less isolated and have access to a larger gene pool.
Unauthorized Stocking and On-line Ponds
On-line ponds (sometimes called in-line ponds) are created by directly damming up a creek or a stream. The pond is in line with the flow of the river, so any water released directly empties into the downstream creek or stream.
An off-line pond is created by the excavation of a low point that then will be filled naturally by rainwater, runoff, or irrigation supplies.
Private ponds can be created for many different purposes including landscaping, irrigation, recreational fishing, etc. Many, if not all, of these intended purposes can be obtained with an off-line pond. Off-line ponds reduce the risk of many negative consequences of pond–building since they are not connected directly to the river system.
Individual landowners can submit an application for the creation of a pond through their state agency listed in the contact information below. Depending on the location, a permit to the U.S. Army Corps of Engineers may also be required.
An on-line pond slows down and holds water of a stream or creek, subsequently changing the volume and sediment load and increasing the temperature of the water in contains. This disruption of the natural flow of water and sediment often degrades the quality of the water. Many individuals stock these “private ponds” with non-native game fish or exotic fish (i.e. Koi). If these ponds are connected to the stream network, large storm events can allow the non-native organisms to escape downstream, causing a whole host of problems for native species.
Native organisms have developed in particular areas over long time periods. If we transfer one species of fish, either on purpose or accidently, many ecological problems can arise. One such example is the illegal release of Alabama Bass (Micropterus henshalli) into the Savannah watershed of South Carolina. These fish are currently outcompeting and hybridizing with native Bartram’s Bass (Micropterus sp. cf. cataractae) and endangering their very survival as a species.
In all areas of the Chattooga watershed (if stocking fish is allowed in the state), a permit must be completed to stock fish by private citizens. This should be under the advice and technical guidance of the listed state agency for each respective state.
Unregulated stockings into public waters can have unintended negative consequences, which can alter the existing aquatic community permanently. Stocked fish can:
- feed on eggs, fry, or adults of existing fishes;
- compete with existing fishes for food and habitat;
- introduce diseases and parasites;
- interbreed with existing fishes, diluting the native gene pool; and
- degrade habitat and water quality.
Unfortunately, once established, stocked fish are nearly impossible to eradicate. Strategies to evaluate and manage the unintended impacts of stocked fish are difficult to implement, often ineffective, and costly.
Lapointe, Fuller, Neilson, Murphy, & Angermeier (2016) state that “Bait release, private stocking, illegal introductions intended to establish reproducing populations (e.g., of sport fish), aquaculture, and the sale of live organisms all create risks for future invasions…”
Protecting Native Brook Trout
Degraded riparian areas do not provide adequate shade, thus allowing excess solar radiation that can warm streams by up to 10ºF. Increases in ambient air temperatures also warm the waters of our rivers and streams. SABT are already on the edge of their thermal limits in the Chattooga watershed; rising temperature not only physically stresses these trout, but it also exacerbates other threats such as competition from non-native trout species.
The major threats to SABT in the Chattooga watershed are: 1. Increasing water temperatures due to impaired riparian areas, climate change, and loss of hemlock species, 2. Competition by non-native trout, 3. Unauthorized stockings and on-line ponds, and 4. Genetic isolation in the headwaters.
Yes, in 2020, the “Burrell’s Place” property on Hwy 107 was put up for sale. This property contained a pond built years ago on the headwaters of Pigpen Branch. This on-line pond for years had been warming the waters released downstream and releasing non-native fish species that were outcompeting the native SABT originally found in the stream. Naturaland Trust purchased the property and removal of the dam started soon after with help from many partners, including the Chattooga Conservancy. In 2023, after many months of removing the dam and non-native fish, native SABT were returned to the stream, opening more than three miles of cold-water habitat for native ecosystems and new angling opportunities.
The removal of the Tugalo dam would return miles of currently flooded tributaries of the Chattooga River to its natural state. These tributaries are ideal SABT habitat for restoration. Brook Trout may already be present in the upper reaches of these currently flooded and isolated small streams. The removal of the dam would allow these stretches to become streams again and restoration efforts could begin to restore SABT to these areas. This would not only restore the natural ecology of these streams, but would further provide cold-water fishing opportunities in South Carolina and Georgia where this type of recreation is often limited.
What steps can citizens take to improve SABT habitat and SABT survival in the Chattooga watershed?
Citizens can take many steps to improve SABT habitat and ensure the future survival of the species in our watershed.
- If you own land, maintain an intact vegetated buffer around any waterbodies. A minimum buffer width to maintain water quality and habitat commonly ranges from 75 to 100 feet. Avoid any land-disturbing activities near or in the creek, which can cause sedimentation that can smother fish eggs and further slow and heat up the water.
- Use local wood for fires, home heating, etc. as transporting over distances can further spread exotic pests of tree species, such as the hemlock woolly adelgid, emerald ash borer, Asian long-horned beetle, and oak splendor beetle.
- Voice your opinion with state agencies that SABT should be valued more than other non-native trout species in restoration and stocking decisions.
- Support alternative energy sources when you can to help reduce the impact of climate change in our watershed.
- If you must build a pond on your property, consider an off-line pond and stock with native species.
- Never transport fish from one water body to another. Stocking of any fish should be done legally under the supervision of the appropriate state agency.
- Get out and enjoy your native SABT and help educate others on their importance in our native ecosystems.
Learn More
Click the link below to find our references and sources for further reading about Southern Appalachian Brook Trout.
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