*Please check the Lake List at www.uwsp.edu/cnr/uwexlakes to make sure your organization’s contact information is current. If your lake organization has not completed the 2006 Lake Organization Directory Update contact uwexlakes@uwsp.edu or 715-346-2116.

To the citizen lake monitor and professional lake manager, the Secchi disk is an indispensable tool for assessing lake clarity. The Secchi depth measurement is valuable because it is simple, low cost, relates well to our general perception of a lake’s clarity, and can be compared to a large historical database. Yet we tend to interpret this measurement in a variety of ways. Sometimes we consider it a rough measurement, giving a ballpark estimate of a lake’s clarity. At other times we rely on the Secchi disk as a quantitative tool to help make costly lake management decisions. So should the Secchi disk measurement be considered a ballpark tool or a highly precise instrument? The answer is that it depends on the precautions taken while making the measurement.

Secchi disk readings depend on four basic elements: sunlight, water, the Secchi disk, and our eye. While a lake’s water clarity itself is the major contributor to the measurement, these four elements, the weather, and our technique can create external factors that result in variations in readings. The more important of these are:

• Whiteness (and blackness) of the disk

• Altitude of the sun

• Surface ripples and waves

• Shadow of the boat or observer

• Surface reflections off the water

• Clearness of the sky

• Observer vision characteristics (e.g., abnormalities, adaptation, sunglasses, etc.)

• Number of repeated measurements

Because of external influence, investigators consider the Secchi depth an apparent optical property of the water. An inherent property would not have external influence. This does not make the Secchi depth measurement a poor measurement. But it does bring home the point that minimizing the external factors, or making them as constant as possible, is important to make the measurement precise. Following a well-defined measurement protocol is essential to maximizing the value of the Secchi depth measurement.

For example, taking the Secchi depth within the 10 a.m. to 4 p.m. period recommended in Wisconsin helps minimize the influence of the sun’s altitude. Based on one study of the solar altitude effects, Secchi depth values would vary by about 6% due to altitude changes in mid-summer Wisconsin over the 6-hour measurement period. Over the full May-September period, the variation increases to 15% because the sun’s altitude is lower at the beginning and end of the summer season. Taking measurements outside the times recommended in the protocol will tend to introduce additional variability.

Another example is the effect of waves. Most monitors have experienced the difficulty of taking Secchi depths when the lake is rough and try to take readings when the lake is calm. Waves contributed to an average 10% decrease in Secchi depth values when 5-inch waves were present in a recent study. This study and others have demonstrated that a view-scope (a tube between the eye and water to block out waves and glare) can decrease this effect of waves.

The variations caused by individual factors can exceed a 10% range. The total variation resulting from several factors can increase the variability far beyond that of just one factor. Although studies to date demonstrate potential protocol improvements, the studies are insufficient to be sure that changes would produce an overall benefit, especially in light of the large existing Secchi depth database using the current protocol. Furthermore, a protocol change that increases complexity must be weighed against the possibility of reducing the number of times that monitors truly follow the protocol. The Wisconsin Citizen Lake Monitoring Network is conducting several studies this year with a goal of reducing measurement variability, thereby improving ability to detect "real" clarity variations of a lake over time as well as differences among lakes.

In the meantime, careful attention to following the existing protocol will keep variation to a minimum. One step all monitors could add to improve precision, or reduce variability, is to take several consecutive readings on the day of sampling and report the average. Averaging several readings is a sound method to reduce variability in measurements. In fact, following the protocol and averaging a few consecutive readings could reduce the uncertainty for a day’s reported result to just a few percent.

To read this article in its entirety go to http://www.uwsp.edu/cnr/uwexlakes/laketides/vol31-2/Secchi%20Article%20-%20Full.pdf

The full Secchi depth protocol for Wisconsin is at http://dnr.wi.gov/org/water/fhp/lakes/selfhelp/forvolunteers.htm.

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Things are being improved and expanded in the Self-Help Volunteer Lake Monitoring Program. One of the things that will change is the name. Welcome to the Citizen Lake Monitoring Network (CLMN)! The new name will better reflect who we are - a network of citizens helping agency staff monitor Wisconsin lakes.

Laura Herman, former DNR Self-Help Coordinator, is the new UW-Extension Citizen Lake Monitoring Network Statewide Coordinator and will oversee the education and training aspects of the network. In 2006, the CLMN will add 80 new chemistry volunteers and 100-plus new Secchi volunteers to the current 1600 volunteers. The data volunteers collect is kept in electronic format and that too, is undergoing improvements.

The DNR is developing a new and improved database called the Surface Water Integrated Monitoring System (SWIMS). Instead of having a database just for lake data, we’ll be sharing a database that will hold data on rivers, streams and lakes. In addition to traditional water chemistry and clarity data, SWIMS will hold data on aquatic plants, aquatic invasive species, sediment, and more. Volunteers will benefit from the new system in a number of ways: online data entry will be improved, lab results will be available sooner, and more reports covering a wider variety of topics will be available online. Volunteers will be able to add in lake-specific information on aquatic plants, invasive species, ice on and off records, and other interesting information.

The SWIMS database should be in place during the later half of the 2006 monitoring season, or at the latest in 2007 (for volunteers’ 2006 reports). Volunteers can watch for updates from Jennifer Filbert, SWIMS Coordinator, DNR, for the status and timeline of the database.

Volunteers deserve the opportunity to make the most of their monitoring capabilities and know that the data they collect is high quality and can be used by all. Tim Asplund, Statewide Aquatic Ecologist/Limnologist, DNR, will be working with protocols and expanding monitoring options. He will be developing new Quality Assurance/Quality Control practices, and working to ensure that the data volunteers collect is fully integrated into the state’s lake monitoring and assessment efforts.

Wisconsin citizens have been collecting lake data for 20 years, and our network is known nationwide for its volunteers and quality data. This will never change!

If you want to learn more or become involved with the CLMN, contact Laura Herman, Citizen Lake Monitoring Network Statewide Coordinator, at 715/346-3989 or laura.herman@uwsp.edu.

While we often refer to animals with two external shells as a clam, you might actually
be looking at a mussel. Freshwater
mussels and freshwater clams both belong to the class bivalvia, although there are differences between the two. The largest difference is in reproduction. Mussels require a host fish to attach to, while clams do not.

Mussel reproduction starts with the male mussel expelling sperm into water. As the water moves, the sperm (with luck) end up in a female’s respiratory gills, where eggs are held during breeding season. Once fertilized, the eggs stay in the gills and develop into tiny mussels called glochidia. The glochidia are expelled from the female in spring to early summer when the right host fish is nearby. (The females of some species actually "go fishing" by displaying tissue that simulates prey for the right fish!) The glochidia clamp onto the fish as a generally harmless parasite.

Although this relationship is not entirely understood, it’s believed that by clamping onto the fins or gills of a fish, glochidia are provided with food and shelter until they drop off to live on their own anywhere from two to six months later. The young mussels must attach physically to a host fish in order to survive. If they do not find a suitable host fish within a few days of drifting in the water column, they die. While some mussels will attach to a wide variety of fish, a few have selected only one specific species to serve as host. The whole process seems like a gamble, doesn’t it?

Adult freshwater mussels live burrowed in sand and gravel at the bottom of rivers and streams. Some are adapted to the quiet water and muddy depths of lakes, ponds, and reservoirs. Unlike most animals, which must travel in search of food, their food drifts to them, mainly tiny plants and animals called plankton that are suspended in the water. By drawing water inside their shells through a siphon, their gills filter out food and take in oxygen.

Mussels usually do not move much, but a muscular "foot" helps them burrow and allows limited travel if disturbed by floods or drought. The foot also helps anchor a mussel against strong currents and may prevent a hungry muskrat from tugging it out for dinner! A mussel’s shell, however, provides its main protection from predators.

The hard, calcium-based shells of mussels consist of two halves joined by a hinge. Unique names like monkeyface, purple wartyback, and pink heelsplitter refer to the wide range of shell shape, color, size and texture found among mussel shells. The lifespan of freshwater mussels varies widely. While some species live for only 10 years, others may live for as long as 100 years.

One species that used to be found in the St. Croix River is called the elephant ear. The skipjack herring is the only host fish to this species. The skipjack used to swim up the Mississippi to the St. Croix. When the river’s lock and dam system was installed, the fish could no longer navigate its way upstream. Without host fish, the elephant ear is dying out. Currently there is only one known remaining elephant ear in the St. Croix River, a male who is somewhere over 80 years old. When he is gone, this species is gone from the St. Croix forever.

In the lakes and rivers where they live, mussels’ filtering ability makes them natural water purifiers. They play an important role in the aquatic food chain as a food source for wildlife such as muskrats and otters. They also can tell us something about the health of the environment on which we all depend. Because mussels respond to changes in water quality, gradual mussel die-offs or sudden mussel kills are reliable indicators of water pollution problems and other environmental health concerns. Stable, diverse mussel populations generally indicate clean water and a healthy aquatic environment.

There are nearly 300 North American freshwater mussel species in the United States, compared to only 12 in all of Europe. Yet most of these species need protection. The American Fisheries Society believes 72% of these species are extinct, endangered, threatened or of special concern. In Wisconsin, 19 of 51 species are listed as threatened or endangered, two of them are also listed as federally endangered. No North American group of animals is in this much trouble, or declining as rapidly. Native mussels constitute the largest group of federally-listed endangered or threatened species.

Many factors affect the health of mussels and can contribute to their demise. Pollution can destroy their environment and kill them as they filter impurities. Excessive silt can cover a mussel or a mussel bed, smothering the animals. Channels and dams built for navigation and/or flood control change the nature of the river in ways that help some species of mussels but devastate other species, such as the elephant ear in the St. Croix. Exotic, introduced species such as the zebra mussel threaten native mussels by competing for food, oxygen and living space.

Freshwater mussels are one of the most diverse and important resources in Wisconsin and perhaps one of the least known. What do these silent residents of your lake or river tell you?

The Langlade County Land Records and Regulations Department has developed a one-of-a-kind website for individuals who are interested in planting native vegetation on their shoreland property. The website gives step-by-step instructions which walk property owners through the differing stages of shoreland restoration. The property owner simply answers four questions about each area of their property they plan to restore (soil type, soil moisture, gradient of slope, and sun angle), and then the program gives information on plants that will grow there.

The website contains information on eliminating invasive weeds, soil preparation, planting tips, mulching, maintenance, greenhouse contacts, supplemental plantings, the benefits of bioengineering over rock riprap, and the rationale behind planting native species. It includes more than 340 easy to find and locally grown trees, shrubs, wildflowers, ferns, vines, grasses, sedges, and emergent and submerged aquatic vegetation that property owners can use to customize their own shoreland restoration plan.

The new website works for all properties, not just those on the shorelands, thereby making it a handy tool for those property owners who do not live on a lake, but would still like to plant a native garden. To access this website, type www.co.langlade.wi.us into your search engine, click on County Departments, Land Records and Regulations, Zoning-Shoreland, and Restoring Native Vegetation.

Lake Planning

Thinking about a lake planning project? Perhaps you recently heard someone say, "We need a lake management plan!" Responses may include: Why bother? What for? What is it? How do we do it? What will it cost? There is no question that planning has benefits, but before a lake organization embarks on a planning effort, these are important questions to answer. With a clear understanding of why we are planning and what we are planning for, the process will be much more productive. The tradition of lake planning in Wisconsin is really quite deep, going back 40 years or more, with varying but mostly positive results. Planning efforts can be frustrating though. Informed participants with clear expectations and an understanding of the process are keys to successful outcomes.

To encourage and foster our planning tradition on Wisconsin’s "jewels," we will present a series in Lake Tides that will explore and explain the lake planning process, the step-wise building blocks and methods used to create a plan. Also addressed will be ways to get the plan approved and most importantly, implemented!

Planning is a commitment. Perhaps the most important step in successful planning is to clearly determine why we are doing it. In general, planning allows communities to control their fate. Planning can correct past problems, protect and improve on current conditions, and provide a guide to the future. It seeks to minimize conflict and undesirable conditions while proceeding to attain things that are valued by communities. Planning helps assure that money spent on projects is expended in a meaningful and effective way. It may be required for, or aid in, qualifying for grants or to get approvals and permits to conduct lake improvement activities.

What is a plan? Planning is an ongoing process, which is what this series will be about. We want the process to ultimately lead to a comprehensive lake management plan -- a guide to taking care of aspects of a lake ecosystem including water quality, fisheries and wildlife, shorelands and watersheds, recreational use and others -- as opposed to a narrow view of just one element or "problem." Ideally, in the plan these elements are considered in detail and have goals and associated strategies, priorities, schedules and budgets to guide implementation of projects to protect and improve the whole lake.

That’s a tall order! To get to a comprehensive management plan will take time. There are several steps along the way but we don’t have to wait until the end to take action. Each step can be designed to lead directly to taking action while continuing to build your plan. Remember, it is a process.

In future Lake Tides, we will describe these steps and how to achieve them while emphasizing actions that can be taken to protect lakes. The next installment will cover the first step of building a successful lake management plan. If you have specific planning topics or issues that we should discuss or if you have success stories, tips and experiences you would like to share, contact Carroll Schaal at Carroll.Schaal@dnr.state.wi.us or (608) 261-6423.

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WAL workshops create great opportunities for lake enthusiasts to learn about issues affecting Wisconsin’s lakes, meet other lake enthusiasts, learn from the experience of other lake groups, and make personal contact with lake management professionals. The workshops include a blend of special guest speakers, presentations from lake experts, panel discussions, insights from local lake leaders, and hands on learning opportunities.

Registration for these events includes refreshments, luncheon, and program materials. Visit the Wisconsin Association of Lakes website for workshop agendas and registration details at www.wisconsinlakes.org, or call 800-542-5253 (in Wisconsin only) or 608-662-0923.

Workshops, field trips and lectures about the impacts of invasive species are scheduled throughout the state this June. A calendar of upcoming invasive species events, educational fact sheets, articles, and resources about invasive species can be found on the Wisconsin Council on Invasive Species http://invasivespecies.wi.gov/awareness.

See http://clean-water.uwex.edu/wav/events.htm for information.