Friday, June 22, 2012

Goldline Darters in Alabama

Brett Albanese, Lucas Hix, and Chris Yator from Georgia Department of Natural Resources and Evan Collins of TNACI.
     Last week TNACI biologists Bernie Kuhajda and Evan Collins met Georgia Department of Natural Resources biologists Brett Albanese, Lucas Hix, and Chris Yator on the Cahaba River in Alabama in search of federally threatened Goldline Darters (Percina aurolineata); this species gets its name from the gold line above the black blotches along its side. It is endemic to the Mobile Basin and is restricted to the Cahaba River in central Alabama and the Coosawattee River in northern Georgia. The study is looking for genetic differences between the Alabama and Georgia populations of this very rare fish. A small piece of fin tissue was removed from each specimen that will be used for genetic analysis by professor Steve Powers at Roanoke College in Virginia. The group was able to catch 56 Goldline Darters from 8 localities, most in shallow water flowing over gravel and larger rock (cobble). Forty additional fish species were also collected; the Cahaba River is the most diverse river for its size in the United States, with 130 species of fishes recorded.

Goldline Darters (Percina aurolineata) with the lower specimen showing the gold line above lateral blotches. These six were all collected in one seine haul!

Collecting for Goldline Darters in the Cahaba River at Piper and in Schultz Creek.

Our first site was the Cahaba River in the town of Centreville, where 34 species of fishes were collected, including several Goldline Darters.  This site is very diverse for fishes as it sits on the Fall Line, an area that separates the upland to the north (Valley and Ridge province) with the lowlands the south (Coastal Plain province) and therefore has both upland and lowland fish species. This is the most downstream site for Goldline Darters. Other fishes collected are shown below.

Male Greenbreast (above) and Rock Darters (below) (Etheostoma jordani and E. rupestre) found in shallow fast water with gravel and larger rocks.

Nuptial male Tricolored Shiner (Cyprinella trichroistia) with breeding
tubercles on top of head and snout.

Similar-looking common Mimic Shiner (Notropis volucellus, top) and federally endangered Cahaba Shiner (N. cahabae, bottom); note Cahaba Shiner lacks downward expansion of lateral stripe just before base of tail and darker tail (caudal) spot.

We collected Goldline Darters upstream in the Cahaba River proper at four other sites with the most individuals (20) collected near Helena approximately 40 miles upstream from Centreville. We tried to get Goldline Darters from their most upstream site in the Cahaba (another 8 miles upstream from Helena) but were unsuccessful.

Goldline Darters were also found in all tributaries where they are known from, including Schultz and Shades creeks and the Little Cahaba River. The largest population is in Shades Creek (13 specimens collected), which was just discovered in 2006 along with federally endangered Cahaba Shiners (Notropis cahabae). Before this discovery Shades Creek had been considered polluted and only a few tolerant fish species were known from upstream localities.

Updates on the results of the genetics study will be posted when available!

We caught this Alabama Map Turtle making a nest and laying eggs. Very cool!

Shades Creek site was just discovered in 2006 to have Goldline Darters as well as Cahaba Shiners!

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