Drought and Trout

If you believe the folks at the N.C. Drought Management Advisory Council, our county was still in "exceptional drought" as of Jan. 15. While we're far from being out of the woods, I don't think "exceptional" fairly characterizes current stream and groundwater conditions locally. The French Broad here in Rosman has been holding at 2 feet above gauge or better since late December, and water levels on the North, East and West Forks are ideal right now, as far as fly fishing goes. We took two groups to our private waters on the North Fork last week and had a splendid day, hooking a dozen or so trout apiece on stonefly nymphs and Baetis emergers. We caught fish in places that were bone-dry back in August.
The Davidson River looks worse off to me, yet it has been fishing fairly well considering the low water temps, especially below its confluence with Looking Glass Creek. I had a banner day fishing the Big D last Friday, before the snows hit. Rains had brought water levels & temperatures up, and the bite was definitely on. A Juju Baetis was the killer fly, but I got fish to eat 10 or 11 different patterns over the day. One silver lining to the drought is that it makes sight-fishing a breeze. The water is so clear you can watch them eat your nymph from 15 feet away! The flip side is you have to be ultra-stealthy to get that close.
I've gotten several phone calls and e-mails recently from clients inquiring how the ongoing drought will affect their spring fishing plans, and I told them quite honestly that I'm optimistic about our spring prospects. For one, the long-range forecasts call for even more rain, on top of all the snow that is slowly recharging the water table. And two, I don't subscribe to the gloom-and-doom soothsaying you see in various chatrooms.
Yes, the drought may temporarily shift segments of the trout population around, maybe even reducing the number of larger browns. But wild trout (which are the only trout I truly care about) are hardy creatures; they bounced back from the post-Ivan and Katrina flooding a few years ago, and they recovered from the 3-year drought that preceded that. Nature endures, and local trout populations will emerge from the latest drought stronger than ever.
If you don't believe me, consider the findings of some of our best scientific minds who have actually studied the effects of drought on trout.
"Drought, like flooding, is a natural phenomena which has been part of the evolutionary history of fish species through the temperate regions of the world," aquatic biologist J.W. Chapwick wrote in 2004. "Trout have developed both resistance and resilience mechanisms to overcome problems associated with extremes in flow." Chapwick's study of two Colorado drainages found that young-of-the-year trout actually increased on the Arkansas during its lowest flow on record.
Closer to home, biologist Molly Keaton of Furman University and two associates also found greater numbers of juvenile and YOY fish after three consecutive years of drought on two South Carolina Piedmont streams, "suggesting that most species exhibited greater reproductive success following the drought."
It makes sense, really. What an impediment to survival it must be for juvenile fish when, freshly hatched out, they are buffeted by high spring flows.They can hide out in the slack-water areas on the current's periphery, but when the water is up, larger fish are able to easily sneak into those areas and prey on them. It's purely anecodotal, I know, but I definitely noticed an increase in the amount of smaller rainbows and browns in the Davidson this past season.
In the Great Smoky Mountains National Park, aquatic biologist Matt Kulp reports that the Park Service's monitoring surveys indicate trout densities have not changed much at all. Indeed, juvenile and sub-adult survival has been very good. Adult mortality has been higher, but Kulp points out that natural mortality annually kills 60-70 percent of adult rainbow trout, irregardless of drought.
So I'm not worried much about the current drought's long-term effect on our local trout populations. I'm much more concerned about the loss of hemlocks along our streams, which threatens to increase summertime water temperatures, and about the impact that global warming will have on our future trout populations, especially native brook trout. Two climate models predict that a little over half of natural brook trout habitat in the southern Appalachians will be lost over the next century, according to U.S. Forest Service researcher Patricia Flebbe. Droughts come and go, but their duration and intensity may very well be linked to the ridiculous amount of greenhouse gases we produce in this country. Something to think about next time you fire up the Hummer for that fishing trip into the mountains...
Tight lines!