The Lake and the Ledge

The Lake and the Ledge

The two obvious topographical features that dominate the surroundings of my hometown, Fond du Lac, Wisconsin are the Niagara Escarpment and Lake Winnebago. Fond du Lac and its smaller neighbors: Taycheedah to the east and North Fond du Lac to the west, occupy the entire south shore of Lake Winnebago, the largest lake in the state. The lake is roughly thirty miles long and five to ten miles wide. Despite its size, it is a shallow body, probably not more than twenty feet deep anywhere. My family home for most of my teenage years, was located in the village of Taycheedah on Willow Beach.

Willow Beach is a stretch of shoreline that is about a mile long. The lake bottom there is sandy with a very gradual drop-off. While swimming, we could walk as far as a city block into the waters that still would be only chest high. Diving was discouraged for this reason. The overall shallow nature of the lake occasionally created some strange lake level deviations while we lived there.

Think of Lake Winnebago as a saucer filled with water. When the wind was unusually strong from the north, the water in the lake would be blown to some degree into the south end. Occasionally the lake level rose two or three feet and washed over the breakwater in our yard. The winds in Wisconsin prevail from the north and west and so, the opposite oscillation occurred only once in the years we lived there.

The wind was so strong out of the south that it blew the water into the north end of the lake. This created a seiche and the waterline receded dramatically along Willow Beach. Our neighbors and we were able to walk out onto the dry lake-bed about the distance equal to a city block. It was a good opportunity to remove debris from the beach. Gradually the water returned to its normal level.

According to the Wisconsin Department of Natural Resources pamphlet, the Winnebago pool lakes system is home to the largest naturally sustaining, Lake Sturgeon (Acipenser fulvescens) population in the world. These fish are used as an egg source for Lake Sturgeon reintroduction or rehabilitation throughout its natural North American range (Wisconsin Winnebago Pool Lakes Sturgeon Spearing Regulations and Information, 2005, p5).

Slow to grow, females can live to be eighty to one hundred years old. They do not begin to spawn until they reach the age of twenty or twenty-five and then do so, only every 4-6 years. A large female can lay up to a million eggs in a season. A younger, smaller male then fertilizes them. The Department of Natural Resources (DNR) says that Winnebago sturgeon spawn in late April and early May along the rocky banks of the Wolf River. There, volunteers stand guard around the clock for the five to seven day spawning period to protect the vulnerable fish from poachers (Wisconsin Winnebago Pool Lakes Sturgeon Spearing Regulations and Information, 2005, p16).

Beauty is in the eye of the beholder. To my eye, a sturgeon won't win any beauty contests. Called a living fossil, the New York Department of Environmental Conservation says that Lake Sturgeon grow to a length of five feet or more, have a flat, under slung, cone-shaped snout, and four barbels or "whiskers" on their chin. Their brownish green body is torpedo-shaped and covered with rows of bony plates and their skin is leathery without scales. Sturgeon have no teeth and are bottom feeders, eating small snails, clams, slugs, lake fly larvae and the like, which are ingested by a sucking action (Lake Sturgeon Fact Sheet, p 1, 2).

There is no hook and line season for sturgeon on Lake Winnebago. However, annual spearing is allowed during a brief two to sixteen day ice-fishing season in early February. Each person spearing for sturgeon is required to hold a permit and if he takes a fish, he must tag and move it immediately to one of the registration stations set up around the lake. The sturgeon catch from the Winnebago Pool lakes is limited each year to a predetermined harvest cap.

In order to prevent depletion of the sturgeon population, the Wisconsin Department of Natural Resources closely monitors the daily catch and the season is immediately closed when the limit is reached. According to the DNR, the average annual harvest of sturgeon in recent years has been about 1500 fish. In 2004, the number of licenses sold approached 9,000 (Wisconsin Winnebago Pool Lakes Sturgeon Spearing Regulations and Information, 2005, p3, 4, 13).

During sturgeon season, anglers stalk these aquatic vertebrates. In their dark ice shanties, they crouch over a four by six-foot hole cut in the ice, spear in hand, peering into the murky waters below them. A decoy may be lowered into the water to attract the big fish. When a sturgeon swims into view, the angler attempts to spear the creature. The refraction or bending of light rays by the water makes this is a tricky maneuver and one that is often unsuccessful.

DNR statistics show that nearly 5,000 fishing shanties were counted on Lake Winnebago during the 2004 ice-fishing season. The record sturgeon ever taken from Lake Winnebago was speared during the 2004 event. It was six and one half feet long and weighed 188 pounds (Wisconsin Winnebago Pool Lakes Sturgeon Spearing Regulations and Information, 2005, p13). Aside from the thrill of catching such a large fish, many consider the smoked meat of the sturgeon to be a toothsome delicacy.

The general health of the Winnebago Lake system is closely monitored by the Department of Natural Resources. In 1989, the Winnebago Comprehensive Management Plan was completed and implemented. It required all homes and communities around the lake to create sewage collection and treatment facilities. My Dad was a member of the "Taycheedah Sewerage District." We teased him and called him "the commissioner." This group organized the implementation of a sewerage collection system for the town of Taycheedah. Within ten years, as lakeside residents and communities stopped the discharge of their untreated sewage into the lake, its water quality improved dramatically.

Another concern is the invasion of non-native species into the Winnebago lake system. Several have been resident in Lake Michigan for years. Two of considerable
concern are the sea lamprey and the zebra mussel. Sea lampreys are primitive jawless
fish native to the coastal areas of the Atlantic Ocean. With the bypass of Niagara Falls and the subsequent development of locks and canals between the Great Lakes, the sea lamprey was able to invade all five lakes by 1946 (Fetterolf).

The lamprey is a predator and kills by attaching its round mouth to another fish and sucking its blood or body fluids. As the lamprey population ballooned in the Great Lakes, the native fish suffered a precipitous decline. Several states and Canada have taken measures to curtail the sea lamprey population and the Sea Grant Institute figures show that their numbers have been reduced in the Great Lakes by 90% (Sea Lamprey). The lower Fox River is the outlet for Lake Winnebago and drains into Lake Michigan. To preclude the unwanted invasion of Lake Winnebago by lamprey via the Fox, the locks on that river were closed and permanently sealed in 1988 (Wisconsin Winnebago Pool Lakes Sturgeon Spearing Regulations and Information, 2005, p8).

Another problem species is the zebra mussel, a tiny bottom-dwelling clam native to Europe. The DNR indicates that the zebra mussel was unwittingly introduced into the Great Lakes in the 1980's. They came as hitchhikers in the ballast water of commercial transoceanic vessels (Zebra Mussels. 2004). Boats, divers, anglers, and animals can and do spread this mollusk and their young.

According to the DNR, zebra mussels have unfortunately invaded all of the Lake Winnebago pool lakes (Zebra Mussel Infestation as of December, 2004). The DNR has organized concerned citizen volunteers to educate the angling and boating public in Wisconsin about the measures that must be taken when moving boats and other equipment overland from one waterway to another. The volunteers also inspect watercraft at boat launch sites around the state (What You Can Do! Take Action to Stop Invasive Species).

The spread of the zebra mussel is having serious commercial, environmental, and recreational implications for Wisconsin. They form clumps of clamshells around the water intake lines of power generating stations and other commercial ventures. Such operations are required to employ divers who clean these sites annually. They foul boat motor housings. The small creatures, in great numbers, filter such a large volume of lake water in a day that they create greatly increased water clarity. This upsets the natural balance of microscopic plants and animals. The larger animals, intern, are deprived of their natural food sources, and suffer. The zebra mussel is here to stay, but residents are doing all they can to limit it to those waters where it is currently known to exist.

The Niagara Escarpment is the other prominent land-form in the Fond du Lac area. A rocky bluff or ridge, it can be traced from the eastern edge of town, north along the shore of Lake Winnebago, through Door County, along the north shores of Lakes Michigan and Huron, and down across southern Ontario to upper New York State. There, the Niagara River tumbles over the eastern end of this same feature as the famous Niagara Falls. To the south of Fond du Lac, it extends into Illinois and in its entirety, forms a Brobdingnagian horseshoe shaped land feature. Locals refer to it as the "ledge" and many fail to recognize its geological significance.

"The Niagara Escarpment is recognized as one of the world's unique natural wonders" (About the Niagara Escarpment: Geology of the Escarpment 2005). Geologists have found a continuous saucer-shaped bed of erosion-resistant dolomite rock that stretches from eastern Wisconsin, under Lake Michigan, beneath the entire state of Michigan and southwestern Ontario. The upturned, visible edges of it are what form the "Niagara Escarpment."

Over many years, the softer neighboring rocks and soil have worn away exposing many bluffs and cliffs. According to the Niagara Escarpment Commission, they are several hundred meters high in some locations. To the south of Lake Winnebago and in Upper Michigan, the escarpment is often concealed by glacial deposits (About the Niagara Escarpment: Geology of the Escarpment 2005). The bluffs contain fossilized remains of various life forms from the Silurian Period, some 450 million years ago (Dutch).

My hometown, Fond du Lac, Wisconsin offers some intriguing and unusual attractions for visitors and residents alike. As a child, I enjoyed the opportunity to explore the ledge and the lake. Fond du Lac has always been a special place to me and I feel fortunate to have lived in an area with such interesting physical features.

Sources Consulted

About the Niagara Escarpment: Geology of the Escarpment. 2005. Retrieved July 4, 2005 from Niagara Escarpment Commission Web site: http://www.escarpment.org/Geology/about_geology.htm

Dutch, Steven. The Niagara Escarpment. Retrieved June 29, 2005 from the University of Wisconsin, Green Bay Web site: http://www.uwgb.edu/dutchs/geolwisc/niagesc.htm

Fetterolf, Carlos. Sea Lamprey in the Great Lakes. Retrieved July 4, 2005, from United States Geological Survey's Biological Resources Division Web site:
http://biology.usgs.gov/s+t/SNT/noframe/gl129.htm

Morgan, Alan V, Russell, Peter I. What is the Niagara Escarpment? Wat on Earth. Retrieved June 29, 2005 from the University of Waterloo, Faculty of Science Wat on Earth Web site: http://www.science.uwaterloo.ca/earth/waton/niagara.html

New York State Department of Environmental Conservation. Lake Sturgeon Fact Sheet. 1, 2. Retrieved June 30, 2005 from Web site: http://www.dec.state.ny.us/website/dfwmr/wildlife/endspec/lakestur.html
Sea Lamprey. Retrieved July 4, 2005, from University of Wisconsin Sea Grant Institute, Fish of the Great Lakes Web site:
http://www.seagrant.wisc.edu/greatlakesfish/sealamprey.html

What You Can Do! Take Action to Stop Invasive Species. Retrieved July 4, 2005 from Wisconsin Department of Natural Resources Bureau of Water shed Management Web site: http://dnr.wi.gov/invasives/action_water.htm

Wisconsin Department of Natural Resources Bureau of Fisheries Management and Habitat Protection. Wisconsin Winnebago Pool Lakes Sturgeon Spearing Regulations and Information, 3, 4, 8, 13. Madison: Wisconsin DNR, 2005. Retrieved June 30, 2005 from Web site:
http://www.dnr.state.wi.us/org/water/fhp/fish/Winnebago%20Sturgeon%20
Spearing%20Pamphlet%202005.pdf

Zebra Mussel Infestation as of December, 2004. Retrieved July 4, 2005 from Wisconsin Department of Natural Resources Bureau of Fisheries Management and Habitat Protection Web site: http://dnr.wi.gov/invasives/fact/zm/zminfest_year2004.pdf

Zebra Mussels. 2004. Retrieved July 4, 2005 from Wisconsin Department of Natural Resources Bureau of Fisheries Management and Habitat Protection Web site: http://dnr.wi.gov/invasives/fact/zebra.htm