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Wednesday, 16 January 2008 00:00

Park’s brookie population withstands drought well

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By Jennifer Garlesky • Staff Writer

The Southern Appalachian brook trout population is surviving through the drought that has been plaguing Western North Carolina this past year, according to Great Smoky Mountain National Park fisheries biologists Matt Kulp.

Park biologists have been monitoring and collecting data from the park’s streams and research has shown that the brook trout population is sustaining at a normal level.

“This is a native fish and is used to coping with the drought,” Kulp said.

The brook trout is the only species of trout native to the Smoky Mountains. Brown and rainbow trout also share the waterways with the brook trout. However, their presence in the mountain streams is a product of the early settlers.

The logging companies that came to the Smoky Mountain in the early 1900s stocked the streams with brown and rainbow trout. Both of these species are non-native and have contributed to the decline in the brook trout population. The brook trout population also was adversely affected by the sedimentation of mountain streams that was a byproduct of logging.

Data also shows that the park’s brown trout population is at normal levels as well, Kulp said. The brown trout is the largest trout species in the park and can reach up to 25 to 30 inches long and are typically found in lower elevation streams. The brown trout has an advantage over both the rainbow and brook trout when it comes to survival of the fittest. The brown trout have more protein in their diet because they eat other fish and insects. Brook and rainbow eat only insects, Kulp explained. This is an important factor when it comes to survival, especially when a drought occurs.

Because of the insect-only diet of the rainbow trout — which is the most popular trout among the parks anglers, says Kulp — its population has seen a decline during drought. The drought has warmed stream water, he explained. In streams that flow from an elevation of 2,000 feet or lower, there is a 25 to 75 percent decline, Kulp said.

Trout need cold water in order to survive. When the water warms, the fish burns a lot more energy, Kulp explained. When a drought occurs it causes the fish to crowd together in one area. The excess use of their energy and lack of food leads to the starvation of many fish.

The brook trout has had an advantage over the rainbow because of its location in the high-elevation streams. The higher elevation water temperatures are much colder than in lower elevation areas, which has helped the brook trout survive, Kulp said.

Kulp says that even though the trout may be dying at a quick rate, he says, when you look at the fish lifespan it’s not something to be concerned about.

The average trout’s lifespan is three to four years, Kulp said. “They are used to having droughts and floods. Whenever a drought occurs the adult fish population is usually affected. This is opposite of what happens when a flood occurs and the young fish population is affected,” he explained.

Kulp says that this process creates a balance in nature and once waters reach a normal level the fish will begin to reproduce.

“Once they are given the opportunity to bounce back very quick they will,” he said.

 

Restoring the brook trout population

Park biologists are working diligently to restore the park streams with brook trout. Right now the native trout species has 120 miles of stream to live in. By this fall park biologist are planning to dedicate an additional eight to nine miles for the trout.

It is important for the brook trout to have its own space to live in, Kulp said. Species like the rainbow out-compete the native brook and push it out of — or take over — its range, he explained.

Through the restoration work park biologists hope to preserve the species that once swam throughout all the park’s waterways. The goal of the restoration is to have the brook trout population at self-sustaining levels.

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