A Beautiful Northern Lake

I spent several hours with an old fellow that has been experiencing a beautiful lake in the Northwoods for a long time. He raised his children to love fishing and the outdoors on this lake. This lake is a pristine one that so far has resisted the most visible effects of humans. Yet slowly, he has witnessed changes. Perhaps even with good intentions, humans use and management of this lake without understanding the ecological consequences may eventually destroy it.

This man is passionate about his lake and fishing. For decades he and his family have  swam and dove below the waters and watched the fish he pursues for sport and food.  His lake home has no lawn, but he has extended his lake dock in response to water level drops during droughts to have enough depth to float his boat, the mechanism for exploration and understanding his water world. He is the great observer of time and changes on the lake. This man has a thirst for knowledge about his lake and how it ticks.

This man joined other curious and concerned lake residents in forming a lake association. Over the years this lake association has done what they understood were good things for the lake: stocking fish, monitoring water quality, and placing fish habitat structures. The lake association hired a professional lake planner to give them further guidance. A plan was created but as with most plans, the engagement of residents to carry out the plan is hampered by their own personal interest and limited time spent on the lake. Yet, he does his civic duty to his community and does what he can to help others understand what knowledge he has gained through time.

This lake is a pristine lake with all the characteristics that should maintain its quality and integrity if what it offers can be understood. It is what lake scientists define as a mesotrophic lake which means there are plenty of nutrients to promote good growth of all living things in it but not too many or too little nutrients to limit biological activity. Yet, subtle changes have occurred in the lake within the last century. Fish populations have altered. Water levels have oscillated. Water quality has fluctuated. The best aquatic plant species for fish habitat have disappeared from an area. We know that nature is never static and ever changing to adjust to maintain its ecological integrity; but what human actions have altered nature’s ability to adjust to this lake?

Before humans came along and made changes in the name of progress, the evolution of this natural lake over geological time made sure this lake was a stable part of a larger ecological aquatic  community.  This lake, and many others in the headwaters, have been changed into reservoirs.  Prior to the dams, lake water levels and discharges varied with the seasons and climate changes for thousands of years. For over a hundred years now, to meet the industrial needs of the greater Wisconsin River downstream, this natural flow has been changed and controlled.

Also, a century ago, another influence on this lake and others was the stocking of fish. Walleye stocking from both WDNR hatcheries and private stocking have occurred. Transfer of panfish such as bluegills, pumpkinseeds, black crappies, and yellow perch from one lake to another also happens. One must ask “why?” is there a need to stock fish? Of course, the answer has been to “improve” the fishery.  But we seldom have solved the problem as to the “why?” the fishery has declined.

Perhaps, the reasons are the dams. In many cases dams have blocked fish migration from our larger waterway systems for over one hundred years. Walleyes are considered as riverine fish by many fish biologist and are often congregating below dams that do not allow them to reach upper areas to spawn. Many forage fish spawn in rivers and for the rest of their life history live in lakes. These fish support good growth and survival of predator fish in the lake. Once these ‘bait’ fish spawn in the river below they can no longer reenter the lake with the dam in place.

The creation of a reservoir dam increases the water level of  the original glacial lake. Its operation initiates fluctuating water levels in the lake.  Scientists have documented tremendous amounts of knowledge on the negative effects of dams. Flooding of wetlands in adjacent areas of a dammed lake changes the water depth and plant composition of the wetland as well as exposing this new shallow water area to wave action and erosion of the wetland soils into the lake increasing nutrients. The head pressure from the dam can also affects the amount of water entering the lake which would affect water quality. Water level fluctuations in the operation of the dam do not allow the long-term stabilization of the nutrient cycling through the biotic food chain.

Add all these manmade changes in the lake together, subtle changes have gone both noticed and unnoticed even with the most knowledgeable observer. Even with recent scientific methods providing data such as long-term water quality monitoring, plant and fish surveys, shoreline development studies, these manmade changes have eventually influenced the natural evolution of a lake or even a chain of lakes controlled by one or several dams.

Collectively, our efforts to gather information on lakes are giving us data and we are creating scenarios of what our lakes might be like in the future and offering reasons why; but if we do not change our ways, many of our lakes face changes in fish composition and decreased water quality. Why do our managers of our natural resources allow this crisis state of change to occur?

Perhaps, this is a time for a major shift on how we manage our Northern lakes, reservoirs, and river systems. If we look at the history of what humans have done to these lakes and take our collective knowledge of the data and research we have gathered, we can make new management decisions to restore what once were sustainable aquatic systems. Each lake is different, but it is time to create a system where a lake community or several lake communities in an area can lead changes once … they understand the problem. The care of an old fellow now becomes the wisdom of the future.