Fisheries: April-May, 2009

Clipping adipose fin (lower right in photo) of Brook trout for genetic study.

Clipping adipose fin (lower right) for Brook trout genetic study.

NPS photo.

Studying fish DNA and RNA to understand Smokies’ fish populations

From April 13-15, fisheries managers Steve Moore and Matt Kulp worked with USGS researchers Mike Eackles, John Switzer, and Tim King to collect two forms of brook trout genetics data from Smoky Mountain streams. Volunteers were also on hand to carry sample buckets of fish and net shocked fish. The field work took place in Tennessee and the Oconoluftee and Cataloochee areas of North Carolina, up to three miles into rough backcountry.

Two crews at each site hiked to an accessible reach of stream and used backpack electrofishing gear to collect a sample of 30 brook trout. The researchers clipped the adipose fin (behind the dorsal fin) from each fish, and stored the tissue for later DNA analysis. They have noticed that fish practice “positive assortive mating,” which means that fish are attracted to and mate with fish that have similar DNA. (“Positive assortive mating” decreases the range of different DNA in that population—this may allow that group to adapt to a specific environment or have resistance to specific diseases, or it may limit its ability to adapt to outside diseases. Other species practice “negative assortive mating,” which means that individuals choose mates with DNA most unlike their own, which diversifies the population’s DNA overall.)

Over time, positive assortive mating in Smokies trout populations has resulted in streams of fish with distinct DNA traits. Researchers and managers hope to use the DNA information to identify different populations of brook trout, so they will know where to transplant fish to restored streams based on that population’s genetic makeup. They also hope to better understand brook trout genomics—or RNA—which is how genes are expressed in fish physical or behavioral traits.

New display protects rivers

When you’re near Abrams Creek, look for a new educational display about endangered fishes that fisheries managers and park partners helped to produce. The poster-size display stresses that visitors should not pick up rocks, build dams, or clear rock channels. It also succinctly describes the impact of these actions: endangered fish may abandon their nests if they are disturbed, and their eggs may succumb to disease and predators. The display will be posted in the Abrams Creek campground next to Abrams Creek, prime habitat for several endangered species.

Redesigning roads to let fish pass

Fisheries staff assisted park planners and engineers with planning and design aspects of a number of low water fords, bridges, and culverts along the Cades Cove loop road in preparation for repaving of the 11 mile loop. Several of the bridges, culverts and low water fords will be replaced and need to be redesigned to afford fish passage, mitigate flooding and provide for visitor safety during major storm events.

Volunteer river clean-up

Fisheries staff worked with the Little River chapter of Trout Unlimited on a litter pickup along Little River from Townsend to Elkmont campground on April 25. The cleanup was an annual event followed by lunch served to all volunteers at the Metcalf Bottoms picnic area.

Find us at Troutfest!

The fisheries staff will participate in the fourth annual Troutfest ( to be held May 16-17 at the Townsend Visitors Center in Townsend, TN. The free annual event includes educational and live fish displays from the park, TWRA, and UT, casting demonstrations, kids’ activities, food, music, and outdoor vendors of every kind. It is a fun filled event for the whole family, with all proceeds from the event to benefit the Smokies’ fisheries program.

Keeping tabs on water chemistry

Fisheries staff continue to collect 15-minute stream chemistry data (temperature, pH, conductivity, and turbidity) from several sondes (waterproof measuring devices) along the Oconaluftee River as part of ongoing monitoring of the US Highway 441 road construction project. The stream sondes take measures every 15 minutes to ensure that construction activities are not adding additional sediment or other pollutants to the river associated with construction. To date, water quality values have remained within state limits, indicating that all sediment and other mitigation measures are working effectively.

Return to Resource Roundup: April-May, 2009.

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