Protective slot limits have proven a good tool for improving bass fisheries during their more than 30 years of use. But arguably they would have been --- and still could be --- far more effective if anglers followed them as fisheries managers intended.
But about the same time as slots were recognized by wildlife agencies as a strategy for growing larger bass, anglers began to embrace catch-and-release. Too often, those two work at cross purposes, which has prompted managers to rethink how and when to use protective slots, if at all.
“If anything, slots are used less,” said Bill Pouder, a fisheries biologist and regional administrator for the Florida Fish and Wildlife Conservation Commission (FWC). “In Florida, we’ve had one new one in the last 10 years.”
Jason Dotson, an FWC section research leader, added, “Harvest rates are low, usually less than 10 percent. Fisheries managers in the Southeast are not as concerned about overfishing as they were in the 1980s.
“Now, we’re more concerned about growing trophies and providing goods numbers than being sustainable.”
In Texas, meanwhile, fisheries managers have added just three protective slot limits during the past 10 years, according to Craig Bonds, a region director for Texas Parks and Wildlife (TPW). Additionally, seven have been removed in favor of minimum or maximum length limits and a catch-and-release regulation, while six have been modified to shift protection to longer fish.
“Texas fisheries managers have not substantially increased the use of SLLs (slot-length-limits) over the past 20 years,” Bonds said.
“We have maintained SLLs where they have been successful at restructuring largemouth bass populations to make fishing better for our constituents. We’ve removed or modified them where they were not successful in achieving our management goals.”
Why have they sometimes been unsuccessful, not only in Texas but in bass waters across the nation?
A protected slot’s purpose is twofold. First, it is intended to shield a certain size of fish, say 14 to 18 inches, from harvest. Second, it is intended to encourage harvest of fish smaller than 14 inches to reduce competition for forage and habitat brought about by excess recruitment. When anglers follow both practices, theoretically the number of bass above 18 inches increases.
But because of the popularity of catch-and-release, reality often has trumped theory.
“Slots haven’t worked,” said Jeff Slipke, a fisheries expert with Midwest Lake Management, Inc., in Missouri. “For one reason or another, folks are reluctant to keep small bass. So what you’re doing when you use a slot is creating an artificially high minimum length limit. A 12- to 15-inch slot is really a 15-inch minimum.”
In a worst case scenario, that can result in a fishery with an overpopulation of small to medium size fish.
“A lot of the time, there’s ample food for young bass to 8 to 10 inches,” Slipke continued. “Where you start to see stockpiling is at 10- to 14-inch bass because there’s a lack of 3- to 4-inch bluegill for them to eat. When that happens, bass hit a wall and won’t grow anymore.”
When working as intended, the slot reduces the number of bass moving into that protected slot and, thus, the competition for food.
All of this is not to say that slots have not worked. Some of them have, especially when managers closely monitor not only the bass population but angler behavior.
For example, Florida managers replaced a 14-inch minimum with a 15-24 slot in 2000.
“Prior to that, harvest was pretty high, up to 30 percent,” Pouder said. “We wanted to try to redirect effort, to protect the females.”
And it worked, harvest declined to 10 percent, and Istokpoga now is one of the best trophy lakes in the Sunshine State, the biologist said.
Other times, fisheries have improved when the protective slot is replaced with a higher minimum length, as happened in Texas’ Lake Nacogdoches. With a 14-21 protective slot in place, managers noted that too many bass longer than 21 inches were being harvested.
By changing to a 16-inch minimum in 2008, TPW allowed anglers to keep more small to intermediate fish to eat, and, simultaneously, increased the odds of catching a trophy. The latter occurred because remaining bass had less competition for bigger and more desirable forage, allowing them to grow both faster and larger.
A volunteer trophy bass reporting program “revealed exceptionally high catches” of trophy bass following the regulation change,” Bonds said.
What does the future hold for the use of protective slots? Fisheries managers continue to believe that they are an effective management tool, but they also know that how effective depends largely on angler behavior.
The key, Bonds believes, is educating anglers about how harvest of bass below a protected slot improves their chances of catching bigger fish.
“Simple manipulations of consumptive variables (changing the slot and/or the bag limit) will not likely motivate bass anglers to harvest more fish,” he said, adding that TPW has produced a video, “Eat More Bass: Slot Limits Help Grow Bigger Fish,” in hopes of convincing fishermen to do that.
(This article appeared originally in B.A.S.S. Times.)