Goldline darters…

Gilmer County and the greater Blue Ridge of Georgia were featured in two articles in the current edition of Southeastern Naturalist. It’s a scientific journal about research throughout the Deep South. One article is a fascinating look into a tiny fish that survives as a species in two small localities – one in Alabama and one here in the upper Coosawattee River, including Mountaintown Creek.

The Goldline Darter (Percina aurolineata Suttkus and Ramsey) is a small fish that most of us would mistake for fish bait.

Dartergoldline400A
The Goldline Darter. Image courtesy of OutdoorAlabama.com

Not even four inches long, these little guys make their homes in small streams and rivers in the upper reaches of the Cahaba River of Alabama and the Coosawattee River of northern Georgia. The Georgia range of the Goldline Darter appears to be limited to some waterways upstream of Carters Dam. They thrive in shallow streams in which they can live over sand-to-gravel beds and can nest downstream of boulders. However, they’re also considered to be an endangered species by the state of Georgia and a threatened species by Federal wildlife officials.

Did that sort of stream sound familiar? It ought to. Researchers at Roanoke College, in Virginia, and the Tennessee Aquarium Conservation Institute recently published an article in Southeastern Naturalist to discuss their research into the Goldline Darter population that lives in several Gilmer County streams, to include Mountaintown Creek at the Highway 52 (Chatsworth Highway) bridge. The scientists collected fish samples from Mountaintown Creek and other Gilmer creeks to answer questions about whether the Alabama and Coosawattee populations were separate species and whether any conservation plan should lump the two populations or preserve them separately.

The authors discussed how the current thinking is that the Goldline Darter was once a widespread species in the Alabama River, into which Mountaintown Creek eventually leads via the Coosawattee River. A combination of damming (Carters Lake, for example) and pollution probably eliminated them from all but the most remote tributaries, including Mountaintown. The authors did a genetic analysis of tissue from darters that were collected around Mountaintown and other nearby creeks, as well as from darters in the Alabama population. The results: the local darters are closely related enough to the Alabama population that they should be considered members of the same species. However, there is enough genetic separation between them that any conservation plan should try to preserve both populations without co-mingling them.

Have we seen any here? We’re not sure. We first spotted some fish that were very similar to Goldline Darters in East Mountaintown Creek back in December, 2015 (thank goodness for my journal notes!). We’re aren’t fish experts by any means, though, so we might check in with the researchers to see if we can determine exactly what we saw. To be continued….

______

Want to learn more? 

Some sources that I reviewed include:

1.“Testing for Genetic Divergence Within and Among Isolated Populations of a Threatened Species in Georgia and Alabama Percina aurolineata (Percidae; Goldline Darter)”, by Steven L. Powell, Sarah E. Ahlbrand, Bernard R. Kuhaja, and Kelsey E. West, Southeastern Naturalist, Volume 14, Number 4, 2015. 

2. Straight, C.A., B. Albanese, and B.J. Freeman. [Internet]. [updated 2009 March 25]. Fishes of Georgia Website, Georgia Museum of Natural History, cited January 13, 2016. Available from: http://fishesofgeorgia.uga.edu

Advertisements

It came upon a midnight rainy….

And indeed it was much like “Winnie the Pooh and the Blustery Day”: a blustery day turned into a blustery night. Wow! What a lot of rain! But how do you see a real measurement of what’s going on in the creeks?  Ever been away but you wanted to know what’s happening back in Mountaintown Creek? For that let’s go first to the US Geological Survey. In crossing some of our local river bridges you may have seen something like this:

img_0011
An automated river gauge. Photo courtesy US Geologic Survey

Ever heard a newscaster say, “the so-and-so river is at X number of feet at the Highway 1 bridge?” No one stands out there with a yardstick – thank goodness! – to measure that. Instead, USGS uses an automated station that includes a sophisticated “yardstick” and rain gauge to monitor river height, discharge rate (how many cubic feet of water pass per second), and local rainfall amounts. Older gauges look more like metal barrels. You can see one easily on the west side of the Ellijay River bridge on Old Highway 5 north of town. These stations capture the data and transmit it in real-time to the USGS. The USGS then makes the data available to the public and the National Weather Service. The National Weather Service’s River Forecast Centers monitors the USGS data so the Weather Service can issue watches or warnings of “flash floods” or “areal floods“. These forecasts are monitored by local media and public safety officials, which then relay those alerts to the public.

The Southeast RFC covers our area. Its website includes a map of all of the automated river gauge stations in the RFC’s forecast area. Sure enough, we have one for our little corner of the world. It’s MNCG1 -Mountaintown Creek. It’s a gauge on Highway 282, known locally as Tails Creek Road.

mtnga
The map view of the Southeast River Forecast Center’s river gauges. MNCG1 is on Mountaintown Creek – south of Mountaintown itself – on Tails Creek Road. Courtesy National Weather Service. 

According to the U.S. Geological Survey, this station is maintained with the Georgia Department of Natural Resources’ Environmental Protection Division.

Why is MNCG1 a good indicator of what’s happening upstream in Mountaintown? MNCG1 is the closest gauge as well as the first gauge downstream of us. As a downstream gauge it will usually be a lagging indicator of what’s happening upstream. Unfortunately we have no gauges that are closer in this watershed. The ideal situation would be if we had a gauge upstream of us.  Nevertheless, let’s see what’s going on locally:

mtnriv
By 9 a.m. Christmas Eve the Mountaintown Creek station indicates that the creek level was falling from a 10-foot crest between 6 a.m. and 9 a.m. The fall continued through “press time”.

As of 10 a.m., Mountaintown Creek had crested – at least momentarily – and was receding. The gauge had monitored fairly steady river levels since 3 a.m. on December 23. After 9 p.m. on December 23, Mountaintown’s level rocketed up from roughly four feet to ten. By 9 a.m. it appeared to be dropping. As a “lagging indicator,” MNCG1 would indicate that the creek has already fallen upstream in Mountaintown.  Now, will it continue to drop for us? We’ll see. It it raining again after a break this morning. Mountaintown and MNCG1 are close enough that they ought to get the same amounts of rain. Any extra rain that falls in the upper reaches of the watershed, though, may create a “pulse” of higher flow & stream height that won’t reach MNCG1 for a period of time. Until any pulse from the latest rain gets there, MNCG1 may reflect a further drop in stream height.

Merry Christmas!