Clarks Hill Stripers Finding A More Oxygen-Rich Thermocline

A new oxygen system on Clarks Hill is making for better striper water.

Don Baldwin | July 31, 2013

Summer is a great time for outdoor recreational activity, particularly if it has anything to do with water. Clark Hill, near Augusta, is a favorite of local residents and fun seekers from both Georgia and South Carolina who show up in large numbers to enjoy this beautiful body of water.

Clark Hill is a fine fishery and well known for its excellent lineside population. A few weeks ago a group of friends got together and held a little tournament on the lake, and the stakes were high. Bragging rights!

Four of us from Atlanta, including myself, Paul Perkins, Ron Rich and Creighton Fearrington, and three from the Augusta area, David Boiter, Dennis Columb and Josh Davis, split up into two teams and went out on the lake with high expectations. And rightfully so, we had selected two well-known Clark Hill guides to lead us in our efforts. We met Mark Crawford, of Lincolnton, and Ricky DuBose, of Aiken, South Carolina, before daybreak, at a ramp near the dam, and by first light we were on the water.

Soon we were in about 40 feet of water near the east end of the dam with blueback herring dangling at the end of downlines and rods in the rail-mounted rod holders. I was in the boat with Mark, and his graph was showing the characteristic arches of big stripers. He was tapping the bottom of the center-console boat with a cut-off pool cue.

“Tapping the bottom of the boat will often turn fish on when they would otherwise not feed,” said Mark.

And, as if well scripted, we could see a fish on the graph start moving up toward the baits.

We boated several stripers in the 5- to 8-lb. range near the dam and began moving upstream as the sun rose higher in the sky.

Mark said through the summer months, he looks for surface activity early, as hybrids school up and attack threadfin shad. But during the heat of the day the stripers are likely to be in the thermocline in about 60 feet of water. During the summer, the water near the surface heats up and a layer of much cooler water sinks to a depth of between 50 and 70 feet. The sharp difference in temperature between the hotter and cooler water is called a thermocline.

“While the water at that depth is the ideal temperature for the big stripers, oxygen levels have posed a problem in the past,” said Mark. “This condition has been helped considerably by the addition of an oxygen-supply system that was installed in the lake in 2011 (see sidebar on page 33).”

We fished until noon and hit several locations upstream from the dam as far as Horseshoe Island. Between the two boats, we landed 35 stripers. Most of the fish were between 5 and 8 pounds, but we had several in the teens and one just heavier than 22.

A tally between the boats was about even, but bragging rights for one of the boats was certainly established.

The setup for this pattern isn’t complicated. Mark uses casting reels, spooled with 20-lb. test monofilament, mounted on 7-foot Ugly Stick rods.

“The Ugly Stick has a soft-enough tip to allow the fish to hook themselves and enough backbone in the butt for fighting a big fish,” said Mark.

The terminal tackle is a 1 1/2-oz.weight with a swivel embedded in each end. A 17-lb. test fluorocarbon leader of 3 to 4 feet and a 2/0 kahle hook completes the rig. Hook a lively blueback herring through the nostrils, and you are ready to go. Mark said that fresh bait is crucial to success.

“The stripers like the bait lively and natural looking,” said Mark. “If you think the bait got hit, replace it.”

Ricky and Mark both recommend leaving the rods in the holder until the striper pulls the tip down into the water.

“A big one will pull the rod four eyes deep,” said Ricky.

That’s how he named his guide service. There is no need to set the hook, just start cranking and raise the rod.

For surface action, Mark recommends a Spook, Sammy, fluke or any action bait that makes a commotion.

“When the hybrids are busting bait, they are pretty aggressive,” said Mark.

Electronics play an important role in downline fishing. Both guides cruise around likely areas looking for fish on the graph. When fish are located, the bait is counted down to just above the level of the fish. Place the rod in the holder, and get ready to reel. Ricky said stripers will often stack up in bunches in the thermocline, so once you see fish, or catch one or two, hang in there for a while; there are likely more close by.

A mistake committed by most beginners is that they don’t buy enough bait. Mark buys a minimum of 6-dozen bluebacks for even a half day trip.

“When the fish are on, you go through a lot of bait,” said Mark. “And it is a really bad feeling to be on active fish and run out.”

Mark said good supplies of healthy bluebacks are available at the Herring Hut or Palmetto Angler bait shops. You’ll need an aerated bait tank with round corners to keep the herring alive, and a little salt in the water won’t hurt.

While this type of fishing might sound simple, and on the surface it is, the key is knowing where to look for the stripers and how to read a graph properly. Going with a guide like Mark or Ricky will get you moving in the right direction, and you can easily progress from there.

Mark said this bite will last through the summer and well into the fall. In fact, downlining is pretty effective throughout much of the year.

Contact Mark Crawford at or call him on (706) 373-8347 and book a trip. Or maybe do like we did and gather up a group of friends and set up two boats for a little friendly completion. Ricky DuBose can be reached at (803) 507-4300.

Clark Hill’s Oxygenation System Helping Stripers

Deep-water reservoirs, like Clarks Hill, share a common problem. In the heat of the summer the water sets up in layers called thermoclines. Warm water is less dense than cool water, and the cooler layer tends to sink while leaving the warm water on top. Stripers prefer the cool water and will move to it, but this deeper water is typically deficient in DO (dissolved oxygen) making it less than optimal for the fish. Herein lies the problem of supporting healthy striper populations in deep-water reservoirs during the summer.

At Clarks Hill, the Corps of Engineers worked out a solution that appears to be having a positive impact on the situation. About 5 miles upstream from the Strom Thurmond Dam, near Modoc, the corps suspended a series of nine oxygen lines at varying depths through a stretch of the lake.

During the summer, oxygen gas is supplied to these lines, and the oxygen is released along the length of the lines through small openings. The concept can be thought of as a large aerator much like you would find in a household aquarium. The system is simple but apparently effective.

The lines were put in place in 2011, and over the last three years the schedule has been as follows:

Year       Oxygen Start        Oxygen End
2011       June 8                   Oct. 13
2012       June 4                   Oct. 10
2013       May 28                  TBD

The oxygen tubes are placed upstream of the dam to allow for a longer stretch of improved oxygen levels as the current moves downstream.

The South Carolina DNR is conducting tagging and tracking studies to better understand the impact of the projects, but, if you ask local anglers, they’ll give the corps high marks. The striper population seems to be thriving, and there is still plenty of action even in the heat of the summer.

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