Bass Population Thriving at Lake of the Ozarks
A bountiful bass population will make for an exciting fall at Lake of the Ozarks, but one of Mother Nature’s annual quirks could slow down some of the action.
“From a fisheries biologist standpoint it is a pretty boring population because it never changes,” says Greg Stoner, Missouri Department of Conservation (MDC) fisheries biologist. “It is always good because we don’t see fluctuations in year-class strength and growth rate like they do in some other lakes. In this lake we have very stable recruitment and very stable growth rates so the population doesn’t change much from year to year.”
Tournament weights have increased in recent years, which could be an indication of a couple of years of above average recruitment in the bass population. “You will see that reflected in the tournament catches and angler catch rates because there is a higher percentage of big fish out there,” says Stoner.
The fisheries biologist notes the Lake of the Ozarks scored high on the RSD metric, which is a stock density measurement that determines the percentage of catchable bass (8 inches or longer) in a body of water. The percentage for Lake of the Ozarks was determined by dividing the number of legal-size bass (15 inches and larger) by the number of bass under legal size that were taken during electrofishing sampling by the MDC. “That number generally runs about 22 to 25 percent of the fish, so about a quarter of the catchable fish in the lake at any given time are legal fish,” says Stoner.
A major factor aiding the yearly recruitment of Lake of the Ozarks bass is the abundance of docks that provide plenty of cover for young bass. “We probably have more cover in this lake than Truman or Pomme de Terre have,” Stoner says. “There are 25,000 docks on this lake and maybe a third of the people put brush out around their docks so that is a lot of brush. “
With such a large bass population the fishing should be easy during this fall since the water is cooling down and bass are feeding heavily in preparation for winter. However the fall turnover could curtail some of the action. Stoner believes anglers can use the turnover as a viable excuse for struggling in the fall if they are fishing in an affected area. “I don’t know if the fish feed differently then or all of sudden they can go anywhere,” says Stoner.
Bass can go anywhere during or after the turnover due to a mixing of oxygen through various water layers. “To understand turnover you have to understand the characteristic of water in lakes called stratification,” says Stoner. “When coming out of the winter and into the spring, water starts warming up and you will get a layer down to 25 feet called the thermocline. Above that there is an area called the epilimnion where all the photosynthesis takes place and where your oxygen is at. When you get to the thermocline there is a rapid drop in temperature but also a rapid drop in oxygen. Below the thermocline is a layer called the hypolimnion which is devoid of oxygen in the summer. So by the end of summer you have these three distinct layers set up. “
The top layer of water is lighter in density than the thermocline, but when cooler weather arrives in the fall, the warmer top layer cools down and becomes denser. As the water continues to cool, the surface water’s density continues to increase causing the layer to drop and mix with the thermocline. The turnover occurs when the upper zone cools to the same temperature (somewhere in the 50-degree range) as the bottom so there is no difference in water density and stratification has broken down. This allows the similar densities and temperatures of the water layers to mix and create the turnover.
Water affected by the turnover usually has a milky green tint to it. Some areas will be covered on the surface with bits of moss and bubbles, which is the result of algae dying and decomposing in the cooler water.
Turnover typically occurs from mid- to late October but will start sooner if the weather has been unseasonably cooler in late summer or early fall. Stoner notes the upper tributaries turn over first, and it might take three weeks to a month for the turnover to spread throughout the whole lake. That means anglers will always be able to find sections of the lake unaffected by turnover.
Another fall phenomenon anglers should pay attention to is the shad migration. Stoner believes the cooler water temperatures and food supply in the fall draw shad to the backs of coves. “If there is a good warm, sunny day the baitfish will be in the backs of the coves,” he says. “They are also putting on the feedbag for winter and they feed on plankton. When the water is warm on sunny days there will be more production of plankton in the coves.
“If the sunlight can hit the bottom sediment it is going to make it a little warmer and algae will grow on the sediments that the shad will feed on,” says Stoner. “Shad don’t just swim around and pick plankton out of the water. If you go to the back of the coves and see bubbles coming up, that is where the shad are pecking at algae on the bottom.”
The biologist also suggests looking for gulls in the coves to find large concentrations of baitfish.
Stoner recalls winning a tournament at Lake of the Ozarks during the fall by keying on big schools of shad in the back end of a tributary. He caught all of his fish throwing a 3/4-ounce Rat-L-Trap that he let sink 10 to 15 feet deep into the schools of suspended shad.
For information on lodging and other facilities at the Lake of the Ozarks or to receive a free vacation guide, call the Lake of the Ozarks Convention & Visitors Bureau at 1-800-FUN-LAKE or visit the Lake of the Ozarks Convention and Visitors Bureau web site at funlake.com.
Copies of John Neporadny’s book, “THE Lake of the Ozarks Fishing Guide” are available by calling 573/365-4296 or visiting the web site www.jnoutdoors.com.