October 04, 2010
A recent assessment of Grayson, Dewey and Carr lakes reveals how the 15-inch minimum-size limit is working (or not) on these three northeastern state impoundments. (July 2008)
Photo by Ron Sinfelt.
The largemouth bass is Kentucky's most sought-after species of fish. So it's not surprising that when it comes to fisheries management, much time and study are spent to make bass fishing the best it can be in every public waterway.
Fishery biologists with the Kentucky Department of Fish and Wildlife Resources (KDFWR) use a variety of methods to keep tabs on bass populations. They have several ways to manipulate populations, but each lake environment is different and poses a different set of circumstances to consider before management can make decisions.
Broad-stroke regulations are often easier for anglers to understand and remember, but a more specific set of rules is sometimes needed to control the harvest of bass and shape the population into a higher quality fishery. Certain limits generally produce a particular outcome. It's the biologist's job to look at all the factors and recommend the best approach.
Of course, the toughest factor to contend with is nature itself. At times, nature will deal managers an unpredictable hand or permit only a finite number of options.
And some waters are simply better suited for largemouth production and growth than others. In Kentucky generally, those waters to the east pose the biggest challenge.
Three of the major reservoirs where biologists are continually working to offer the best bassing possible are Grayson, Dewey and Carr Creek lakes. In recent years, a number of variables have affected the largemouth populations in these waters. As biologists have learned more from research, and as environmental factors have changed from year to year, they have employed numerous management techniques.
One thing anglers will commonly notice on these waters is the 15-inch minimum-size limit on largemouths and smallmouths. As most anglers know, spotted bass don't have a size limit: In most waters, the overwhelming majority of spots die of old age before they reach 15 inches, so regulating them under that limit is essentially pointless.
Additionally, spots compete some with largemouth for space and forage. Since largemouth are the more desirable species, keeping Kentucky bass numbers at bay through harvest may help bucketmouths to better growth and survival rates.
We'll take a little look at the history of Grayson, Dewey and Carr Creek, explore some of the issues biologists have contended with, and see how the 15-inch limit has worked on these waters in recent years to improve fishing success.
Let's start with the biggest lake of the three.
"Over the years, Grayson Lake has experienced a number of management practices aimed at trying to improve the quality of the largemouth population," said Fred Howe, assistant fishery biologist for the KDFWR's Northeastern Fishery District.
"A number of years ago," he said, "Lew Kornman (head of the Northeast District) initiated the 15-inch limit because the quality of Grayson bass was lacking. This measure helps protect bass from harvest longer, so they have a chance to get larger.
"It has improved the average quality of the fish, as intended. But as in many eastern reservoirs, productivity, fertility and other factors still play big roles in the overall quality of the bass fishing in Grayson."
Most of the time, when a 15-inch limit is imposed on bass, it's because of high harvest or poor reproduction and recruitment. If a bass population is under a 12-inch limit, a high harvest creates a buildup of bass just under that limit. An 11-inch bass isn't considered a high-quality fish. To get that group of bass over the hump, using a 15-inch limit generally works to improve the number of fish from 13 to 14 inches, and larger.
Another benefit of the 15-inch limit is that when, for whatever reason, a population doesn't have consistently good spawns, protecting all the bass until they hit the size limit provides a better potential for getting the best spawn you can. Under a 15-inch limit, there are simply more fish to spawn than under a 12-inch limit.
Grayson Lake has received a number of supplemental bass stockings over the years -- in fact, all three of these reservoirs have -- in an attempt to improve the number of catchable bass. Studies have indicated that surviving that first winter is critical to having good year-classes make it on up to harvestable size. Depending on the availability of bass for stocking, and on which lake appears to need some help each year, extra largemouths are released to keep the population on an even keel.
Sometimes, stocked fish survive better than those that reproduced naturally. To avoid big drops in bass numbers from year to year, biologists use a formula to determine what the balance of natural reproduction and added fish should be.
"One year, we released 12-inch bass that were fin-clipped, so we could identify them later to see how they were doing," said Jeff Ross, KDFWR assistant director of fisheries. "The next check showed very few of those fish were still present.
"Officers advised us that anglers were catching them left and right and taking them out before they had a chance to reach 15 inches long. So we found that approach wasn't going to work.
"Putting in 5-inch bass when needed -- and when we have the capability -- and letting them grow to legal harvestable size, turned out to be more productive in keeping available a higher quality fishery," said Ross.
"We tend to get good spawns and have a lot of little bass out there," said Howe. "But because the lake isn't very fertile and because forage and habitat are limited, they don't make it to big sizes in big numbers.
"Fertilization of Grayson is difficult to get much out of because the exchange rate is so high. The water flushes through it in such a short period of time that fertilizing has only minimal effects," he noted.
"Grayson is sometimes a tough lake to bass fish," said Howe. "It has a lot of cliff-lined banks and not a lot of cover. Anglers who put time in on the water will be more successful, and those who fish the upper part of the lake are going to find more largemouth. The lower lake holds more spotted bass."
Howe expects the 15-inch limit to remain in place for a while, and fishery managers wi
ll continue to examine possible ways to improve bass fishing even beyond what the 15-inch limit has made better.
The same is true of Dewey Lake and Carr Creek, both of which are located in the Eastern Fishery District just south of Grayson.
Here again, the 15-inch size limit is aimed at keeping the general quality of the largemouth populations better than they would be under the general statewide 12-inch limit.
Said Ross, "One development we've had on Dewey, which might help improve the growth of small bass, is the growth of weedbeds over the last year or two.
"We've got zebra mussels in Dewey now, and Kevin Frey -- our district biologist -- reports they're clearing the water up enough for some of the rooted aquatic plants to take hold.
"Small bass find food easier and in more abundance around shoreline vegetation, as long as it doesn't get completely out of control," Ross said.
Early and late in the day in the summertime, bass anglers will find fish around vegetation and can catch them on several types of lures.
Topwaters and floating worms, along with spinnerbaits, get a lot of attention from bass cruising close to weedbeds looking for baitfish that have been spooked.
Of course, the more the bass have to eat, the bigger they grow. And growth rates play a big role in whether a 15-inch limit works.
In a lake where bass take 10 years to reach 15 inches, the idea of getting more fish up to that size is going to flop. Too many will die of natural causes, and very, very few will ever be available to be taken home.
"A 15-inch limit needs the support of a good growth rate for maximum benefit," said black bass biologist Ryan Oster. "And Dewey is doing well, given all the factors involved,"
CARR CREEK LAKE
Biologists have been evaluating the 15-inch limit on Carr Creek Lake, which until recently has very low productivity for largemouths and limited forage.
Biologists Ross and Oster report that alewives have found their way into Carr Creek, becoming the dominant forage species over gizzard shad.
"Alewives are pretty aggressive at the early stages and they grow quite fast," said Ross. "That translates to two possibilities of their effects on bass in Carr Creek.
"They may compete with fingerlings for food -- which is already limited -- and may not help the first-year bass that much as a food source, because they get too big for the little bass to eat that first year.
"If there's an upside to that species of forage being there," Ross went on, "it might be that since the alewives don't ultimately get as big as gizzard shad, when bass do reach that intermediate range, their growth rates may kick back in, due to more food fish in the system that they can swallow.
"We just have to watch and see how things develop," said Ross.
"Bass have a tough time in Carr Creek, but we want to try to make the fishing the best we can so that opportunity continues."
Each time a new factor arises, it has an effect on all the fisheries in the lake. Sometimes it turns out to be good and other times, not so good.
Biologists are charged with juggling all these factors and reacting to changing conditions, whether created by nature, the activities or attitudes of the angling public, by swings in fishing pressure or the results of regulatory changes.
Grayson, Dewey and Carr Creek lakes have in common one final interesting -- and somewhat unique -- characteristic: the likelihood of a higher harvest rate on largemouths than in lakes where the species is better suited.
On these lakes, the fishing pressure on bass probably isn't quite as high as on some others in Kentucky. But on these waters, the practice of keeping bass to take home seems to be more prevalent.
Some biologists speculate that in many of the eastern reservoirs, it's tougher for anglers to routinely catch many keeper-sized largemouths. So when they do, they tend to take those fish home. After all, a good catch isn't something that happens every time they go out bass fishing.
When the lake has good growth rates, but sampling shows a big number of bass just under the minimum-size limit, that strongly suggests a high harvest of fish that have hit their legal size.
If you want a group of bass better than 12 inches in a high-harvest lake, the 15-inch minimum approach often helps get some fish past that hump, keeping some higher-quality catch-and-release fish in the mix.
"The scoop for this year on Carr Creek, which is only a little over 700 acres, is that most of the bass big enough to catch are still going to be under 15 inches," said Ross.
Also, he says that anglers may find that several of the fish they catch are spotted bass, which make up a pretty good portion of the bass in Carr Creek. Spots tend to do pretty well in some of the clearer, deeper highland reservoirs, but they don't reach the size that largemouths can.
Is a 15-inch size limit on bass accomplishing what it was intended to do? In some cases, answering that is more a question of getting high angler compliance, than of whether the right management decision was made.
This is true on any waterway and with any management approach -- but maybe even more so on lakes where bass habitat and good growing conditions are both less than ideal.
Some biologists' studies show that management efforts could be more effective in improving things, but only if anglers embrace the regulations more fully. A classic example is removing the size limit on spotted bass, or keeping small bass on lakes where slot limits are in effect.
"To improve the quality of bass populations, we need anglers to keep some bass," said Ross.
"If we use a slot and no one keeps the fish under 12 inches, it really limits the effect of the management.
If we have a 15-inch limit in effect, and if every fish 15 inches or better is going home, there'll be a lot fewer fish of that size in the population.
"And catching nicer bass becomes less likely."
Ross says that by using a simple rule of thumb, anglers who fish any particular lake several times a year can help whatever management effort is in place. On lakes like Carr Creek, Grayson and Dewey, where conditions for bass production aren't always optimal, try this: If nearly every fish you catch is under the size limit, then consider even putting back even the ones t
hat are over it, too.
That will help bolster the population of larger fish. If you want fish to eat, maybe think about keeping a different species.
If you consistently catch fish over the size limit, that indicates a population that's doing very well, and keeping a few bass won't hurt.
Many factors affect the dynamics of fish populations, and fishing doesn't always remain the same from year to year. When bigger bass seem a little scarce and you do catch one, putting it back is the logical thing to do because the fishery can benefit from that.
Remember that on relatively small lakes like Carr Creek, Dewey and Grayson, when the numbers of big fish are limited, their release can really make a difference.
Think about it -- if you've caught one, so have others over the course of a fishing season. In smaller lakes, putting those bass back in the water may have a greater benefit than in a giant reservoir that can potentially hold a lot more bigger bass.
"Since that 15-inch limit has been in place on Grayson, and also, I think, on the two lakes in the Eastern District, it's made a difference in anglers' ability to catch many better-sized bass," said Howe.
"Can we make it better by doing some other things? Maybe we can do some tweaking here and there. But mostly, we'll just have to keep adjusting to the cyclic things nature pitches at us -- to take advantage of when it's good, and try to minimize bad effects when it goes down.
"When we learn something new or see the populations change, we look hard at how we can use that knowledge, either to get more out of the fishery for the angler, or fix the problem as quick as we can -- if we can.
"Right now," Howe added, "we think the 15-inch limit on bass is what's best for these lakes. Our goal is to do what's best for the resource, as well as for the fishing public."