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.
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.
