7/8/2017 7:28:00 AM Questions regarding the sustainability issues for
walleye and other game fish in Vilas and Oneida counties
By TJ Dunn Doctor of veterinary medicine
Since the 1960s there has been a well-documented drop off in the numbers of several species of game fish in many of the Vilas and Oneida county lakes. Some species of fish, such as ciscos, walleye, and some minnows, are far less numerous and/or are no longer present in water bodies which historically held large numbers of sustained populations.
Is it reasonable to conclude we are applying previously successful but currently inefficient methods to promote game fish sustainability in some Northwoods lakes? Is there a toxin which hampers the breeding processes of walleye in some lakes? Due to environmental pollutants not present just 60 years ago, do we need new and adaptive thinking based on today's reality of a changed dynamic in fresh water biota? Have we neglected the warning Rachael Carson's "Silent Spring" presented to us nearly 60 years ago?
Perhaps the answers to the poor sustainability of walleye and other aquatic species in many waterbodies lay submerged within the minute plankton nutrients (called producers) dwelling in aquatic environments. Producers are the foundation upon which the health and reproductive success of larger organisms, such as walleye and other fish (called consumers) absolutely depend. Do we need to place more emphasis on analysis, quantifying and stocking the producers at the bottom of the food chain rather than focusing financial and human resources on stocking the predators at the top of the food chain? Have we done an assessment of each waterbody's food base before we stock the top predators into that unique system? If not, perhaps we must.
According to the report, Economic Value of Lakes and Rivers in Oneida County, assembled by Dave Noel and Myles Alexander, the economic impact on Oneida County of poor water quality would result in a major decrease in visitor days to the extent of as much as 100 million dollars in lost revenue. Waterfront property assessment values and taxes from that value decline would be a huge revenue impact on the area.
Quoting Darby Nelson regarding Michigan and Minnesota lakes, he states, "I believe there is very little current analyses of the zooplankton populations in these nearby lakes." How does one measure the biological health of a lake? EPA did it by examining the health of the lakes' plankton community, a key element in the aquatic food chain.
To better understand the current state of diminishing populations of walleye in some northern Wisconsin lakes and in an effort to contribute to a nature-compatible resolution to the quandary, I am prompted to ask the following questions:
If scant quantification and qualification of a lake's zooplankton and phytoplankton have not been a vital part of the sustainability equation, why would we be planting predators into a specific lake expecting to see optimal growth in numbers and quality of the end product?
To ignore the foundational nutritional source for the stocked game fish is equivalent to planting watermelons on a sandy beach and hoping there is a healthy end product to harvest.
Would it not be more logical, economical, efficient, and rewarding if we understood what species of aquatic life currently exist naturally and in greatest abundance in any particular lake prior to game fish stocking?
We should grow the watermelons where they grow the best ... in fertile soil and not in the sand; we should grow the game fish where they would grow the best ... in lakes with optimal nourishing factors for the most predominant game fish predators in that water body. By analyzing each lake or stream individually for the biota thriving there we can then tailor the stocking of either more micronutrients (producers) or specific species of predators (consumers) that would promote self-sustaining game fish numbers. Doing so would avoid expensive, frustrating, bioconflicting influences that block the sustainability of the selected species of game fish.
Shouldn't we stock fish only when we can predict with a high degree of accuracy a bountiful harvest from planting selected fish species that will provide a good return on our investment? Assuming we have analyzed and understand the unique producer species of plankton, insects, algae and bacteria in, for example, Lake Tomahawk, and we have assayed the lake for a wide spectrum of chemical contaminant concentrations, we then can establish a Fertility Factor specific for Lake Tomahawk. As a result of our analysis we understand the fertility factors of the "soil" and then can pick the ideal seeds to sow (and they very well might not be watermelons!).
We already have a good method of collecting game fish eggs via fyke nets, careful handling of the female fish and her eggs, hatchery rearing of fertilized eggs, etc. By possessing a full assessment of the food web for each lake or stream we can select the ideal game fish to sow in each waterbody! Conversely, and no less important, we then know what gamefish species are not likely to grow in specific water bodies. No more frustrating watermelon seeds struggling to mature in unfit soil.
If we established a "Fertility Factor" for Lake Tomahawk and it is discovered the lake is not ideal for planting walleye due to low probability of sustainability why not grow the game fish species that will yield the optimal harvest for that beautiful fish garden?
Perhaps the ideal crop yield as calculated via the Lake Tomahawk "Fertility Factor" would be ciscoes, fathead minnows, lake trout, brown trout, musky and small mouth bass. If harvests are satisfying there will be many happy fishermen; and there are hundreds of lakes whose factors are ideal for planting and growing walleye. Ultimately, if I want to put a few walleye in the freezer I will point my paddle to a lake optimized as a predominantly walleye fishery.
Shall we rethink the fish food pyramid structure we have been following the past 150 years wherein we stock the top level consumers, the predators, and we neglect the dependence upon the producers needed for successful maintenance of top-of-the-pyramid harvest?
Perhaps we should be "stocking" various lakes with micronutrients, phytoplankton, zooplankton, algae, insect larvae, small minnows first. When these producer ingredients are present in adequate densities only then will planting the top-of-the-pyramid predators result in a bountiful and sustainable harvest of game fish species.
The soil: good soil = optimal harvest
The water: good water = bountiful biota
No matter how organic, fertile, or inviting the soil is there will never be a bountiful harvest from planting healthy seeds if the soil is contaminated with harsh or toxic chemicals. It's all connected ... the air, rain, ground runoff, septic system pollutants, and possibly even electromagnetic radiation frequencies from radio and cell towers ... all can damage, pollute, or stifle optimal health and reproduction of various plant, animal and microorganism species in nearby lakes.
Any one of the stressors listed below if present within a biome can be hazardous; when multiple stressors are present the additive impact can have an unexpected and far greater harmful impact where none would have occurred if the stressors were acting alone.
The overriding fact we must embrace as stewards of the Earth is this: Everything is connected to everything else. Modify something here and something (possibly unknown) will happen over there.
It is instructive to note that in the early 1900s the stressors impacting area lakes were few and very unlike what we are experiencing today. With the onset of the industrial revolution combined with "modern" land, air, and water use practices we have created biosphere hazards and stressors to the health of human and animal species globally. Regarding some of the protocols and priorities for stocking fish in area lakes I believe it is an entirely new ball game today compared to a generation ago. The environment has markedly changed ... and we need to respond accordingly.
To become truly successful in establishing sustainability of quality game fish numbers our society must adapt our attitudes to fit the new reality.
The agencies we establish to keep our lakes stocked with quality game fish may need to modify the long held (status quo) practice of continually replenishing the top level of the aquatic food pyramid. Perhaps we need to focus on the Fertility Factors for each lake and then stock the lowest levels of the fish food pyramid customized for that particular lake. Until we do that we will continue to be married to the past, the status quo, the early 19th century methods that were successful before all the stressors listed below were major players in the local and global environment.
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