Weed Removal, Bass population Removal?

Weed Removal, Bass population Removal?

In 2012, Greg Matzke, a fishery biologist for the Wisconsin Department of Natural Resources (DNR), made a startling discovery on Florence County's Lake Ellwood. During a comprehensive fish survey which included spring, summer and fall netting and electrofishing, he discovered that all the lake's largemouth bass were older than age-5. Approximately 91 percent of them were at least seven years old. The absence of younger fish indicated steady recruitment failures. Such losses of bass recruitment over multiple years are unprecedented in the natural lakes of Wisconsin.

"The current largemouth bass population is in serious trouble," Matzke reported. "With no natural reproduction since 2007, bass abundance will drop rapidly, with potential for the complete loss of this species unless the current situation changes."

Matzke next began looking at the lake's panfish populations. What he found was stunning. Panfish abundance had fallen about 75 percent over the last 10 years, with bluegill and rock bass abundance down an estimated 65 percent and 89 percent respectively. Intense sampling throughout 2012 found only a single black crappie under six years of age, showing another alarming recruitment failure. Analysis of Lake Ellwood's northern pike population was even more disappointing: There were no pike under age-8!

The Wisconsin DNR had never encountered such dramatic recruitment failures of so many species simultaneously. He shared his data with other biologists and all were nonplussed. Matzke and his team scrambled to collect more data and tried to find a cause for this collapse. Surveys in 2002 had shown normal abundance, size structure, growth, and recruitment in all of these species. What had happened in the last 10 years to prevent reproduction?


The only thriving species of gamefish in the lake were smallmouth bass. Their abundance and size structure had increased in the last decade and recruitment was high. Because Lake Ellwood's smallmouths were doing so well while the other species were collapsing, the focus turned to the lake's historically sparse but important aquatic plant community. The fish species showing recruitment failure are dependent on aquatic vegetation for spawning as well as cover and food for their young. Matzke noted that smallmouth bass were not nearly so dependent on vegetation.


Year-class strength, indexed using age estimates based on the number of individuals of each year-class captured during a 2012 survey, plotted against the pounds of 2,4-D (not acid equivalent) used to treat aquatic plants in Lake Ellwood, 2003-2012.

The Smoking Gun

Eurasian milfoil was discovered in Lake Ellwood in 2002. Herbicide treatments began in 2003 and increased each year. By 2007, recruitment of northern pike, largemouth bass, and black crappie had ceased. "When I analyzed the data it was obvious that recruitment problems seemed linked to herbicide treatments," Matzke said. When he graphed fish abundance by year-class over the last decade and overlaid a chart of herbicide treatments, he found what he believed was a critical connection. Fish numbers fell as the amount of herbicide increased. In the year following a relatively low application of herbicide (2010), young bluegill and black crappie to a lesser extent reappeared, but their continued health seemed in jeopardy.

"We still wonder what stage of reproduction failed in these species," Matzke said. "Aquatic vegetation plays a major role in spawning site selection and in the survival of eggs and fry. Plants are also the source of primary production providing food and habitat for young fish and prey items, including invertebrates and minnows. It seems likely that one or all of these important phases of reproduction have dwindled in Lake Ellwood."


In April 2013, Matzke met with the Lake Ellwood Association to reveal his data and conclusions. He told the group that the main cause for failed northern pike, largemouth bass, and black crappie recruitment appears to be the loss of aquatic vegetation. "The 2,4-D herbicide used on Eurasian milfoil had been successful in reducing the abundance of this invasive species significantly and other native plants were also harmed by the treatments," he told them. He added that he had no reason to believe the chemicals directly caused reproductive failures, but that their use indirectly caused recruitment failure by eliminating too much aquatic vegetation young fish need to survive. Matzke called for a change in the way the Lake Ellwood Association has been managing the lake's aquatic plants and recommended that chemical treatments for milfoil be stopped.

"We need to promote and strengthen aquatic vegetation in Lake Ellwood," he told the group. "The loss of plants, including the invasive milfoil, has almost certainly wiped out a great deal of forage for young fish."

The Future


Lake Ellwood contains a dwindling and rapidly aging population of largemouth bass, black crappie, northern pike, and bluegill. The DNR began a five-year study in 2013. The team, headed by Dr. Greg Sass of Wisconsin's Fisheries and Aquatic Sciences Research Station, is conducting intensive plant and fish monitoring, along with fish diet studies and plankton evaluations.

Last fall's sampling showed promise. Since chemical treatments have ceased, fish and plant communities have responded. The researchers found strong year-classes of bluegills and largemouth bass, along with more native aquatic vegetation. Matzke hopes that trend continues.

Could chemical herbicide treatments for milfoil and other plants such as curlyleaf pondweed be reducing recruitment in other lakes? No other lakes that have been chemically treated have been surveyed so thoroughly. Recruitment problems due to loss of plant cover could be taking place throughout the region where the invasive plant is being battled. There is no way to know if this is happening, and until now there's been no reason to find out. Biologists in other regions are only now learning of Matzke's findings.

"We want to examine the limnological details behind the crash, so that we can prevent similar situations," he says. Lake Ellwood continues to contain some Eurasian milfoil and likely always will. What's become clear is that its treatment likely caused problems far worse than it presence.

*Eric Engbretson, Florence, Wisconsin, is a professional underwater photographer and his images have appeared in many In-Fisherman publications. This is his first written contribution.

California

From Clear Lake in the north to Perris Lake hundreds of miles to the south, California is blessed with the finest trophy largemouth fishing in the world. A 22-pound behemoth was reported from Spring Lake in 2008 — one of many in the 20-pound range taken since California began importing Florida bass a few decades ago. 'California is the number one trophy state for bass exceeding 15 pounds, ' says David Swendseid — bass pro and tackle rep from the Golden State. 'A lot of the best lakes right now are being kept quiet. People aren't talking, but Southern California lakes in general and the San Diego lakes specifically are producing massive fish. Even private waters are turning out behemoth bass and great numbers. The California Delta is phenomenal for numbers. We're catching fifty bass from 3- to 12-pounds per day there. And we're getting back to big swimbaits — specifically the new, 5- to 12-inch 'S-stroke' and glide baits which are new out of Japan. ' Other venues of note include Diamond Valley Lake, Castaic Lake, Bullard's Bar Reservoir, Casitas Lake, and Shasta Lake. 'The Delta and Clear Lake have established recent B.A.S.S. records for biggest bass (14.6 pounds) and biggest bag (in the neighborhood of 122 pounds), ' Swendseid said.

New York

Sorry, Woody. The best part of New York is outside the city. (Way outside.) 'People don't realize how great the bass fishing is in the Finger Lakes and smaller lakes that have excellent populations of largemouths and smallmouths both, ' says multi-species guide, Frank Campbell. 'The diversity of lakes, from the mountains to the flats, is awesome. New York's stream smallmouth fishing is spectacular in the Mohawk River, the Niagara, and dozens of smaller streams that are completely under the radar from a tourism standpoint. That diversity extends to tactics. Anything you like to do to catch bass, we do it here at some point. ' Lake Erie's eastern basin offers some of the finest smallmouth fishing on earth. The opportunites on Lake Ontario are only slightly less spectacular. Lake Oneida and Lake Champlain belong on anybody's top-100 list of North American bass lakes, and over 200 other lakes grace the Empire State, and most have fair to spectacular bass fishing. The porcine smallmouths of the St. Lawrence Seaway seal the deal. New York belongs on this list.

Wisconsin

Chris Beeksma guides for smallmouths and other species around Chequamegon Bay on Lake Superior. Quality regs (only one smallmouth over 22 inches can be kept) transformed that fishery into one of America's finest. Beeksma sends us photos of 6 pounders way too often. 'We may not have the number of largemouth lakes that Minnesota has, but Wisconsin does have a lot, ' Beeksma said. 'Finding a 7-pound largemouth isn't that difficult, and numbers are great. ' Wisconsin also has Green Bay on Lake Michigan, where an 8.4-pound smallmouth was weighed in at the 2013 Sturgeon Bay Open this year. Smallmouth fishing is nothing shy of stupendous all around Door County on Lake Michigan. Rivers like the Flambeau, the Fox, the Menominee, and the Wisconsin are everywhere in the Dairy State, and most harbor scads of pig smallmouths. The St. Croix River, which forms part of the border with Minnesota, is not only a blue-ribbon smallie hotspot, it's one of the most beautiful streams in America. Below its confluence with the Mississippi, Pools 3 and 4 comprise yet another bassy paradise that the Cheeseheads share with Vikings fans.

Florida

'To me, Florida is the big-bass hatchery of the world, whether they go to Texas or California, ' says legendary pro Larry Nixon. 'Lakes here have some deep water, lots of grass, great spawning habitat, and the best fishing is in the heart of summer when nobody knows about it and nobody's there. ' Okeechobee is back. Not news, but along with Lake Seminole, the Harris Chain, Lake Tarpon, the Everglades, the Kissimmee Chain, and several others — Florida can't be bypassed when naming the top 10 states for bass. 'On Okeechobee, that early-morning Zara Spook bite is nothing shy of awesome, ' Nixon said. 'Anglers overlook the St. John's River, too. If you know how to fish tidewater, the St John's is awesome. The Harris Chain has always been solid, and the Toho-Kissimmee Chain is way up there on my list of favorites for numbers of big fish. '

Texas

'Texas would be my target if the goal was to catch a 10-pound bass, ' says Nixon. 'Odds are much better in Texas than Florida for a 10 right now because of Falcon, Sam Rayburn Reservoir, and Toledo Bend. And, even though you may have a better shot at a 15 in California, the odds of catching a 10 are probably lower than in Texas. ' The waters Nixon mentions and Lake Fork are legendary, having been consistent producers of giant bass for decades. Nobody of right mind would dispute the awesome capacity of these lakes to generate massive populations of largemouth bass, and it's been going on since the impoundments were created. Lake Amistad, O.H. Ivie Reservoir, Choke Canyon Lake, and several others are 'must include ' candidates for any list of America's blue-ribbon largemouth lakes.

Alabama

Two words: Lake Guntersville. Catches are phenomenal right now and it's on the bucket list (pun intended) of every angler who really understands bass fishing in America. 'Alabama's a great bassin' state and certainly belongs on any top 10 list, ' says bass pro and TV host Shaw Grigsby. 'Alabama probably has the best spotted bass fishing in the country on the Coosa and Alabama Rivers. In Guntersville you've got massive largemouths, and trophy smallmouths on Pickwick, Wilson, and Wheeler. ' Pro angler and bass guide Brent Crow claims you can catch a 10-largemouth, a 6-pound smallmouth, and a 5-pound spot all within an hour drive. 'You could do it in the same day, if you get lucky, ' Crow laughed. 'It might be the only place in the country where you could do that. Smith Lake in central-western is another great spotted-bass resource. Logan Martin and Lay Lake on the Coosa River are about 50-50 for largemouths and spots with awesome trophy potential. For my money, bass-fishing heaven is right here in Alabama. '

Georgia

Georgia, home of George Perry's famous world-record largemouth (22 pounds, 4 ounces), is the spiritual Mecca of the bassin' world. It has to share some world-class waters, like Lake Eufala with Alabama, and Clark's Hill with South Carolina. But it has Lake Lanier all to itself. Lanier, like Jackson Lake, was a spectacular largemouth fishery for many years but is now dominated by spotted bass. 'Spots are really taking off in Georgia, ' says former resident and In-Fisherman Editor Steve Quinn. 'And they're getting bigger. Lanier is producing unbelievable numbers of 5-pound spots. ' Huge spots are more common than ever on Lanier and Jackson right now, while historic West Point Lake continues to produce great fishing for largemouths. Bartlett's Ferry (aka Lake Harding) is a small but prolific lake that produces great topwater bites almost year 'round. Bassin' rivers are everywhere in Georgia and are completely overlooked. Pressure is minimal and you can find five different species of black bass in rivers like the Chathootchee, Tennessee, Yellow, South, and Coosa. Lake Oconee, Lake Sinclair, and Lake Hartwell round out a list of prime bass attractions that cement Georgia squarely on this top-10 map.

Michigan

Surrounded by Great Lakes, Michigan is an obvious angling paradise, but few folks from other states realize how magnificent the bass fishing really is. The Wolverine state borders Lake Erie, arguably the finest smallmouth water on earth. Michigan shares Lake St. Clair with Ontario — a world-class stage for equal numbers of 4- to 6-pound smallmouths and largemouths. Grand Traverse Bay, Saginaw Bay, Big Bay de Noc, Little Bay de Noc, the Portage Chain, the Sylvania Tract, Elk Lake, Torch Lake, the Beaver Island archipelago, Lake Charlevoix and 11,000 other inland lakes with bass populations might be enough to lift Michigan to the top of this list. But wait: Michigan has spectacular river fishing for smallmouths in the Grand, Muskegon, AuSable, Menominee, Tequamenon, St. Clair, and many other streams. The bayous on the lower Grand bristle with porcine bucketmouths. (No wonder VanDam's so good. He couldn't fling a dead cat back home without hitting a bass.)

Minnesota

Minnesota has world-class smallmouth fishing in the Mississippi River, Mille Lacs, the St. Croix River, and several other waters. A 4 pounder lifts no eyebrows here, and catching multiple 5-pound bronzebacks in a day is common for good anglers. Smallies over 7 pounds are caught every year — sometimes an 8. And Minnesota lays claim to over 13,000 natural lakes — more than any other state. Most harbor impressive populations of native largemouths, smallmouths, or both. Since Minnesota is primarily a walleye state, bass remain relatively under pressured — even though popularity of bass fishing continues to rise. Minnesota isn't the place to find trophy largies over 10 pounds, but it's a place where catching over 100 per day, with several over 5 pounds, just might be easier than anywhere else. Lake Minnetonka, nestled into the urban outskirts of Minneapolis, is a national treasure. But it's the smallmouth fishing that sets Minnesota apart. For size and numbers right now, only Great Lakes fisheries surpass the Gopher state.

Tennessee

In Them Ol' Brown Fish, Billy Westmoreland details how he caught more 10-pound smallmouths in Dale Hollow than, well, the remainder of the human race across the rest of the planet. If Georgia is the spiritual Mecca of largemouth fishing, certainly the Volunteer State maintains that distinction for smallmouth anglers. Center Hill, Pickwick, Wilson, and Old Hickory certainly stir up the echoes of a halcyon past, yet all probably retain the potential to produce a world-record fish. Like Georgia and New York, streams and creeks get overlooked for smallmouths in Tennessee. 'I weighed a 10-pound, 3-ounce largemouth on Chickamauga this year, ' says FLW pro Wesley Strader. 'The Tennessee River has been on fire from one end of the state to the other. Chickamauga has been just nuts. The great thing about Tennessee is the diversity. We have lowland reservoirs full of grass, highland reservoirs like Center Hill dominated by rock — you can pick the kind of water you want to fish here. Largemouth fishing has never been as good as it is right now on Chickamauga, Kentucky Lake, or Douglas Lake. In fact, bass fishing is better now than at any point I can remember. '

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