Taking leave

Tomorrow marks the end of our longest-ever continuous stay at Birch Lake, or anywhere in the north for that matter. When we used to vacation here at a rental cottage, we talked often about "sometime" staying two weeks. A one-week vacation just wasn't enough, especially when half the first day was consumed by grocery shopping and assorted errands, and the last full day, Friday, required packing so as to check out of the cottage on schedule at 9 a.m. A week really meant about five full days, and halfway through the week I began feeling blue about having to go home. The trouble was that getting away from my business for two weeks was difficult, and another week also meant $850 more in weekly rent.

So we got away from that $850 by spending a couple hundred thousand to build our own place (smart, huh?). And now we're wrapping up a stay of 15 days. The trick is that my job as a freelance writer is portable. Even up here in the sticks I have access to high-speed Internet; that and a computer and phone are about all I need to do my work. So we come up here and I work a regular schedule on weekdays, usually finding an hour for "opportunity fishing" toward sunset. During this stay I took a four-day weekend, so that made things a little more relaxed. An old friend and wife paid us a weekend visit; the following Saturday my entire family came in for a cookout.

Best of all, the Birch Lake gods turned the fishing switch to ON, after some very poor action all through July. While the walleyes were still not much in evidence (I caught two keepers, which we are holding in the freezer for a fish fry), the smallmouth action was furious. Twenty-inchers were almost routine.

Today, the day before departure, was beautifully overcast and calm, almost ideal fishing conditions. So I broke my highly focused work habits and went out for an hour at lunchtime. Parked above my favorite rock bar soaking sucker minnows, I caught (and released as always) three smallmouths from 16 to 19 inches. This evening I motored away once more to use up the last half-dozen minnows and finished by catching another 19-inch bass. Life is pretty good, I must say.

Tomorrow I work part of the day and then we take off for home in Manitowoc. I'm ready to get back into the routine, but I can't say I've had my fill of the north. How about you? What does it feel like to leave your Northwoods hideaway after a week, or two, or three, and get back to reality, whatever that means for you?

The buzz

I don’t know how things are on your lake, but here on Birch there isn’t much point in fishing except when the light is low, which means overcast skies, very early morning (including pre-dawn) and late evening into full darkness. It’s possible to catch smallmouth bass here in the full light of day, but walleyes are light-sensitive and hard to find in sunlit hours.

So, being too lazy to roust myself at, say, 4 a.m. to take advantage of the early bite, I generally head out on the water just as the sun touches the tops of the pines. Soon the sun is gone and night slowly comes on. Then interesting things happen in the air around me. For one thing, mosquitoes come out, whining in my ears even when I’m fishing the mid-lake rock bar, far from shore. Here a little repellant works wonders.

Other times I see newly hatched mayflies heilcoptering over the water. On a few early June evenings I often found myself surrounded by tiny white midges, which had hatched by the millions. As darkness deepens, bats patrol low over the water; I see their shadows against the surface, which still retains a bit of brightness. Now and the when I cast, a bat will veer sharply toward my airborne bait, having picked it up on its echolocating system. Once as I reeled in a lure, a bat struck my taut monofilament line and for a long moment just hung there like a butterfly mounted on a pin.

Now, in August (and this happened last year, too), as the light fades, my boat’s envelope is invaded by flies that hover in place, a few dozen of them at a time, all around me and just above the level of my cap. Together they create a faint buzz – I hear it if I hold still and listen carefully. They don’t land on or otherwise pester me; they just hang in the air, bodies black, wings a blur. They seem shaped like flying ants, though I doubt that’s what they are, as ants I’ve seen on the wing don’t behave that way at all. What I really should do is capture a couple with my hat or with the little net I use to dip minnows from my bucket, and bring them back to the cabin for examination. The Internet being what it is today, I might even be able to identify them, down as far as order, anyway (likely not genus and species). Have you seen flies like this on your lake?

At any rate, things in the air add interest to night fishing, and that’s nice at times when those creatures below the waterline aren’t interested in what I offer.

The lake in bloom

Last week I began seeing a light-green film on the water beside out pier, and I noticed a drop in clarity. This happened last August, too, and for a week or so it got steadily worse before it finally cleared. What I saw then and am witnessing now is known as an algae bloom. It’s disturbing because such blooms generally are signs of degraded water quality. I console myself that here on Birch Lake they are rare, and not too severe, and don’t last very long. So far, the algae seem concentrated along shore, in the shallowest and most likely warmest water. But there are plenty of algae at the end of my pier where overnight I hang my flow-through bucket of walleye sucker minnows. Does the algae bloom with its tendency to deplete oxygen account for the low vitality of the minnows with which I tried (with some success) to tempt smallmouth bass last evening?

From my observation I do not believe Birch Lake is experiencing what biologists call a harmful algae bloom, characterized by noxious blue-green algae (which actually consist of microorganisms called cyanobacteria). The blue-greens emit toxins that can kill fish, and when present in volume will emit foul odors – which are not present here. Perhaps this is what scientists call a “nuisance” bloom of green algae. And truth be told it isn’t severe enough so that I would consider it a genuine nuisance.

At any rate, algae blooms are caused by an excess of nutrients (notably phosphorus and nitrogen) in the water. Mix in abundant sunlight and hot days (which we have had this summer) and calm, shallow water (such as we have along our shoreline) and conditions are ripe for a bloom. Sources of excess nutrients around a lake like ours can include lawn fertilizers, leaking septic systems, and runoff carried in by the feeder creek. Usually the “limiting nutrient” that determines whether a bloom will occur is phosphorus. Add too much phosphorus and algae will multiply.

Have you seen algae blooms on your lake? If you have, it’s a reminder to do your part to keep nutrients out of the water. That means proper care of your septic system (which includes a periodic inspection as well as pumping on the recommended schedule), being careful with fertilizer (ideally using none or at least making sure what you do use contains no phosphorus), and using nonphosphorus soaps and detergents. It also means resisting the temptation to relieve oneself in the water while swimming.

If just one person does these things it won’t make a lot of difference, but if everyone who lives around a lake does them, that can make a serious dent in nutrient contributions to the water. So we all need to watch our own behaviors, talk to our neighbors about nutrients, and make sure the subject comes up at meetings of our lake friends groups or lake associations. Lake water is supposed to be blue, not green. We can all do our part help keep it blue.

The making of a magnet

Just down the shore from our pier on Birch Lake stood a tall white pine, its roots right at the waterline, its imposing trunk angled over the water at about 30 degrees from the vertical. It helped make great pictures, framed against an orange sunset or puffy cumulus on blue sky. We wondered if it ever would tip into the water -- it seemed to be defying the tug of gravity.

Well, now we have our answer. By early summer, the tree had tipped to about 45 degrees, and as I paddled by in a canoe one day I noticed a large, lengthwise crack at the base of the trunk. Surely it was only a matter of time, and from that day on, when heading out in the fishing boat, I made sure to give the tree a wide berth.

A few weeks ago, the old pine did come down, but not with a spectacular splash. It eased down, like a staccato second-hand on a watch, tick, tick, tick. I was fishing nearby when the tree began its official descent. I'd hear a "crack," and then another, and another, every few minutes, and though I couldn't perceive any motion, I knew gravity was winning the fight. That evening as my wife and I lay in bed, door to the screen porch open, we could hear the periodic cracks. The next morning the tree lay in the water, extending out some 60 or 70 feet from shore.

It was sad to see a venerable pine go down -- one much like it stands right at the foot of our pier, canting ever so slightly toward the water. We wonder if one day it will lose its root-hold on the bank and settle slowly down in the manner of its near neighbor.

There is a plus side, though, to this tree's fall. It lies in what already was a fair walleye hole, just off the edge of a bed of emergent reeds, at a U-shaped dropoff that anglers like to call an inside turn. Snorkeling around the tree, I have seen young-of-the-year smallmouth bass darting amid the twigs and browning needles. Last weekend a friend and I fished slip-bobbers near the tree, and he caught a near-keeper walleye. This bodes well -- the old pine is likely to become a fish magnet on a lake that has relatively few truly productive spots. There's only one drawback: To any angler who knows anything at all, it's about as obvious as a spot can be. So this place just down from our pier is likely to attract many visitors.

That's all right. For one thing, I live right here and so can keep a close eye on the spot. And not far down the way in the other direction lie a couple of submerged brush piles that are great fish concentrators in their own right. And their locations are strictly classified.

How DO they breathe down there?

As a kid I once asked a wiseacre friend what he’d done in swimming class that day. He said, “We learned to breathe underwater.” For a long moment I actually believed him; I imagined puckering my lips down to a tiny pinhole opening and somehow sucking the air from the water.

That’s crazy, of course. But then how do fish (and for that matter other underwater creatures) manage to breathe? The short and easy answer is: Fish have gills. A closer look reveals just how remarkable this ability to breathe underwater is.

Now, up here above the water’s surface, the air we breathe contains about 21 percent (210,000 parts per million) of oxygen, which of course is the gas on which we depend. Water contains oxygen in solution, but at nowhere near a comparable percentage. Even very high-quality water, such as in a trout stream, contains no more than about 8 parts per million. That’s 0.0008 percent.

Now, even in the oxygen-rich environment in which we live, it’s pretty remarkable that our lungs can draw in enough oxygen to keep every cell of every bone, muscle and organ in our bodies functioning. For a fish to get enough oxygen out of such a scant supply borders on the miraculous. The fact there is a scientific explanation doesn’t make it any less interesting or less wondrous.

Gills actually work on the same basic principle as our lungs: Exposing a huge number of tiny blood-carrying vessels (capillaries) to the oxygen source, so that the oxygen can migrate in (and carbon dioxide can migrate out). Our lungs contain millions of tiny sacs called alveoli, extremely rich in capillaries, where the exchange of gases takes place.

Fishes’ gills, on the other hand, have a structure of rows and columns of specialized cells, called the epithelium, that can absorb the much smaller concentrations of oxygen found in water. In general shape and form, gills look like a car radiator. Most fish have four gills on each side. There’s a main bar-like structure with multiple branches, like a tree, that gradually branch down smaller and smaller, an arrangement that exposes an enormous (relatively speaking) surface area to the water.

Fish pull in water by lowering the floor of the mouth and widening the outer skin flap  (operculum) that protects the gills. The fish then raises the floor of the mouth, and a fold of skin forms a valve blocks the water from rushing out. This increases the pressure inside the mouth, forcing water out and across the gills. The blood exposed at the gill surfaces contains less oxygen than the water, and so the oxygen migrates from the water into the blood. From there it is pumped around the fish’s body.

One advantage fish have is that, being cold-blooded, they have lower metabolism than we do and need less oxygen relative to their size. If fish were warm-blooded and needed oxygen for energy to sustain their body temperature, they would not be able to survive on the amount of oxygen the gills can extract from the water.

There’s another little issue fish have to deal with: Maintaining the right amount of sodium in their bodies. Saltwater fish live in an environment that is saltier than their bodies, so the gills tend to absorb an excess of sodium, which needs to be expelled. In fresh water, it’s just the opposite: The fish must have a mechanism to keep from losing sodium through the gills into the less-salty water around them. These mechanisms are perhaps a subject for a different time.

Anyway, it’s easy to see just how full of it my wiseacre friend was when he talked to me about breathing underwater. If we want to do that, it is much easier to by scuba gear than to grow a set of gills.

Let's be clear - A snorkel is a great learning tool

For getting to know your lake, there's nothing quite like a mask, flippers and snorkel. I love slipping them on and exploring up and down the shoreline from our cabin on Birch Lake, near Minocqua, Wis. This year our lake is much clearer than in the past, for no reason I can discern. The days have been hot and the skies clear, so one would think conditions should be right for algae (and we do now and then experience a minor bloom here). Instead, the water is crystalline compared to what we're used to. When anchored on my favorite rock bar for evening walleye fishing, I can clearly see the anchor resting beside a boulder five feet down.

Therefore, while often I have taken my snorkel gear to other nearby lakes with clearer conditions, I have kicked my way around Birch in recent days. The neat thing about snorkeling is that the action of the flippers keeps you buoyant with little exertion. That means you can snorkel fairly long distances from shore without worrying that you may get too tired to make it back. (Some people prefer to wear a life vest when snorkeling over deep water, just in case.)

I always enjoy the new scenery I encounter when snorkeling, and I almost always learn something new about my lake. This year I've learned that our rusty crayfish population is bigger than I would have thought just from what I see around my pier. They are everywhere, and some of them are huge. It tells me I need to augment the the efforts of the Friends of Birch Lake and get a couple of my own traps to place along the edge of our reed bed. I also noted some patches of cabbage weeds down the shoreline from our place -- a good sign, after the cabbage beds were all but wiped out years ago when the rusty crayfish population exploded.

The best thing I learned, though, was the exact nature of the spot a short distance from my pier where a brother and I have caught numerous walleyes at times. About 50 yards down the shore and about 50 feet out from the reed bed lies a tangle of brush, probably placed there deliberately as a crib years ago. Hovering over it, I looked down on a couple of smallmouth bass in the upper branches and, down deeper, a dozen or more walleyes, finning in place. They seemed not to notice as I quietly passed over. I fished that brush pile the same evening and caught -- nothing. I suppose that says something about the fickle nature of walleyes, or about my skill as an angler.

After recent heavy rains, the water of Birch Lake remains clear. There are more areas of the lake to explore. You could certainly do worse than to spend some time getting to know your lake from a whole different perspective -- with flippers on your feet and your face behind a mask of glass.

How do you like these odds?

I wrote recently about seeing near my Birch Lake pier a school of hundreds of what I believed to be smallmouth bass fry. Looking at all these tiny fish and envisioning many more such schools around the lake’s perimeter, one could assume the lake will soon be chock full of smallmouths.

The reality is far different. The odds of survival for these fry are exceedingly long. One scientific study used DNA tracking to estimate the success of spawning smallmouth bass on a lake in Ontario. To make a long story short, the study found that only 27.7 percent of male bass that acquired eggs (it’s the male who guards the young after the eggs hatch) had at least one offspring survive to the fall young-of-the-year stage. Just 5.4 percent of all the spawning males produced 54.7 percent of the total number of the fall young-of-the-year, which range in size from 1 1/4 to 3 inches.

To look at it another way, consider that female smallmouth bass deposit anywhere from 2,000 to 10,000 eggs on a spring spawning bed. Even under the best conditions, most eggs don’t survive. They’re vulnerable to changes water temperature and oxygen levels, flooding or sedimentation, disease and predation (as from panfish and crayfish).

When the eggs hatch, the larval fish live off a yolk sac attached to their bodies. Once the yolk sac is fully absorbed, the young fish, called fry and about an inch long, rise from the bed and start eating on their own. For a time the male bass protects the school, but eventually he leaves and the fry scatter. They survive on tiny crustaceans until they are big enough to eat aquatic insects, then larger crustaceans and fry of other fish species that spawned later. As the fish grow, they face the same threats as the eggs – in addition to which all manner of predators feast on them.

When they’re small, they get attacked by bluegills, perch, pumpkinseeds and sunfish. As they grow, they become prey for walleyes, northern pike and muskies. Other enemies, again depending on the fishes’ size, include kingfishers, loons and herons, mink, frogs, and some snakes. The end result is that only a tiny fraction of the eggs laid in a spawning bed, and only a tiny fraction of the fry I see near my pier, ever become adult bass that I try (with limited success) to catch. Yes, nature can be a cruel mother. I am certainly glad the odds of survival for my new grandson, Tucker, are considerably better than for a newly hatched smallmouth bass.

They're not just minnows

Judging from what I saw while uncovering the boat on return to Birch Lake yesterday, some fish have pulled off a highly successful spawn. A large school of fry skittered off as I waded into the water to untie the boat canvas. They were about an inch long and, individually, looked like little more than slender shadows cast against the sandy bottom.

We're tempted to label any small fish we see, especially in schools, as minnows. In reality, minnows are a family of fishes defined not by size but by body characteristics. For example, carp that can grow to 50 pounds belong to the minnow family, as do the shiners, only a few inches long, that we use for bait. Members of the minnow family have one brief dorsal fin with nine or fewer soft rays. They have smooth-feeling, scales that may come off when the fish is handled. They do not have true spines in their fins. They have no teeth in the jaw but have rows of toothlike structures on the bony frame that supports the gill tissues: The teeth are actually in the throat and help grind the fishes' food. Most minnows are in fact small -- they reach a few inches to perhaps a foot long. 

So, what did I see in the shallows near my pier yesterday? My guess is that they were smallmouth bass, since those fish were on the spawning beds just two or three weeks ago. I am not aware that any other fish species have spawned since then. I wished I'd had a little dip net with which to scoop a few up and examine them. When I have done this, it amazes me how much even tiny fish fry resemble the adults they will become. There is no mistaking them. Smallmouth fry, for example, have the signature black-edged tails and red eyes. Largemouth bass have the black stripe down the side, perch the vertical black bars, northern pike the oval spots. And so it goes.

Have you seen fish fry (not minnows) in your lake? Try netting a few and taking a close (brief) look. It will allow you to see what's breeding successfully. Of course, success is a relative term -- hatched fry do not a large or stable population make. The odds of fry survival are long indeed -- a topic for another time.

About those midges

My last post mentioned that midges, besides mayflies, were hatching on Birch Lake recently. Midges of course are tiny white flies that when on the wing look like mobile bits of cottonwood fluff. Believe it or not, trout fishing enthusiasts (or should we say fanatics?) actually tie flies small enough to mimic these things.

While the mayflies at Birch were hatching a week or so ago, the midges were, too. One day hundreds of them clung to the screens of our lakeside porch; a tap on the screen sent them flying; in a few moments they were back. The next day only a few remained. I’ve been down on the lake when midges were thick, a swarm hovering around my head, and if I listened carefully I could hear a faint, collective buzzing.

These were non-biting midges, from the insect family Chironomidae, and often called chironomids. Some call them “blind mosquitoes”; others call them “fuzzy bills” because of the males’ bushy antennae. As with mayflies, if your lake has midges, that’s a sign the water quality is pretty good. Midges are an important link in the food chain in and around a lake. Fish and predatory water insects eat them, and the midge larvae help keep the water environment clean by eating organic debris.

Like mayflies, midges have interesting lifecycles. The adult flies lay gelatinous masses on eggs on the water surface, each holding as many as 3,000 eggs, which sink to the bottom and hatch in about a week. The larvae dig into the mud or, in some species (and there are many) build small tubes to live in. They feed on organic matter suspended in the water and mixed with the bottom mud. As they grow, they turn pink and eventually dark red, at which point they are known as bloodworms. The color comes from hemoglobin, the same compound that makes our blood red; it allows the larvae to “breathe” in the mud, which of course is low in oxygen.

After two to seven weeks (largely depending in water temperature) the larvae become pupae. About three days later, they swim to the surface, and adults emerge within several hours. The adults then mate; they live only three to five day and do not feed. In the heat of summer, midges may complete their lifecycle in as little as two or three weeks. Fall larvae do not pupate but instead remain in the larval stage until spring.

Have you seen midge hatches on your lake? Watch for them throughout the summer – several generations may hatch before the season turns to autumn.

Up from the Bottom

There are visitors to the screens of our lakefront porch this week. A number of mayflies and countless tiny midges cling to the screens and, for that matter, to the siding of the cabin. They’ve come up from the bottom of Birch Lake and up to our place, more than 75 feet back from the water and up a considerable hill.

One thing I know about mayfly hatches is that they don’t help the walleye fishing. But that’s not the main point of interest. Are mayflies hatching on your lake? Maybe you already know their story and where they come from, but in case you don’t, here it is.

Mayflies are insects that belong to the scientific order Ephemeroptera, a name no doubt chosen because these flies are ephemeral. The adults, with their triangular wings that propel them in silent flight in a posture that resembles a man with a jet backpack, live only two nights. They have no functioning mouthparts because they don’t eat – they have no need to. During their brief time in the air above a lake, male and female mayflies mate in swarms. The female deposits eggs as she flies low over the water or dips her abdomen. Some species (there are many) even submerge themselves and lay eggs underwater.

From eggs, mayflies develop into adults through several stages of molting. Different species have different molting stages, which also can vary with temperature and water conditions. The insects in immature stages swim to the surface or grab onto rocks or plants. There, according to the Texas A&M University Agri-LIFE extension website, they molt in minutes or second into winged subimagoes, which fly quickly from the water to nearby plants. There they molt again into adults (imagoes) that fly out over the water to begin the mating cycle anew.

Mayflies are the only group of insects that molt after they have wings, says the Texas A&M website. In all other insect orders, winged forms are found only as adults. A typical mayfly lifecycle lasts one year.

Immature mayfly stages have chewing mouthparts and feed by scavenging small pieces of organic matter, such as plant material or algae that accumulate on rocks or other surfaces. Mayflies require water relatively high in dissolved oxygen, which is why they thrive in fast-flowing trout streams. If your lake has mayflies, that’s one sign (certainly not the only indicator) that it’s in decent condition.  

So how did the mayflies affect the walleye fishing here on Birch Lake? Well, yesterday afternoon I caught two, one of them a 17-inch keeper that I brought back to join another already in the freezer as a fish fry for my wife and me. I put the fish in a landing net and set it on the pier while I moved my boat cover from the pier onto shore. Before I made it back to the net, the walleye flopped free and into the water. There went dinner.

Fishing was deadly slow last evening. Could be the mayflies, could be the east wind that brewed up, could be the Birch Lake gods working their will. Could be plain old angler ineptitude. There are too many variables on which to base a conclusion.

Bass on the Beds

Birds nesting, newborn fawns trying their legs, toads and frogs singing in the swamps.  These are all spring magic, but none greater than fish spawning in the shallows of the lakes. Older brother Steve visited our Birch Lake cabin two weekends ago, and while fishing we spotted smallmouth bass tending round gravelly beds they had cleared of sand and silt so as to lay and hatch their eggs.

Now, anglers sometimes debate whether it’s OK to fish for bass while they’re bedding. I can buy the argument that it’s not altogether sporting. Drop almost anything onto a bed and the bass guarding it is compelled by instinct to pick it up and move it away. So an accurate cast to a bed is almost certain to trigger a strike. And it is in fact a bit too easy.

As to whether fishing for bedded bass harms the population, most of what I read says it doesn’t. If you release the bass where you catch them, they’ll go right back to the nests. And in my lake there are essentially no bluegills or other interlopers to eat the eggs for the few minutes when the resident bass are missing.

So Steve and I prowled along the shoreline looking for light-colored circles in the rocky, gravelly areas, finding them often next to sunken logs. Since I am at the lake much of the time and Steve is a once-or-twice-a-year visitor, I mostly just steered the boat, not fishing the beds myself, satsified just to aid and abet and show my big brother a good time.

Birch Lake holds trophy smallmouths, and Steve caught at least one measuring more than 20 inches – 20 and three-quarters to be precise, just as long as the biggest one I’ve ever caught there. He got one or two that might have crossed the 20-inch threshold but that we didn’t bother to measure. If we had been into the taxidermy thing, Steve would have had himself a trophy for the wall, but we both prefer just to let smallmouths go, in some cases after snapping a picture.

We didn’t overdo it – we stopped after had Steve caught half a dozen bass – all lip-hooked and released unharmed – and had enjoyed one of the better fishing times of his life. By the time I get back to Birch again this weekend, I suspect the spawn will be over, the beds empty, the smallmouths in a resting phase, so that I must focus on walleyes. And that’s fine. If some bass are still on their beds, I may just let them, content to observe. I'm just glad I got to witness the spring ritual of smallmouth bass creating the next generation of their kind.

If you love lakes, read this book

To paraphrase an old saying, there are lies, damned lies, and book jacket blurbs. So when the publisher says on the back of Darby Nelson's paperback, For Love of Lakes, that the book is "in the tradition of Aldo Leopold's A Sand County Almanac," you are temped to say, "Yeah, yeah..."  Well, I have read Sand County multiple times and I have read For Love of Lakes, and in my humble opinion the two book titles do belong in the same sentence. Nelson's book is that good.

As one who has loved lakes all my life -- first Lake Michigan on whose shore I grew up and then multiple lakes in Wisconsin's Northwoods -- I found this book enriched me on several levels. Nelson, like Leopold, combines the sensitivity of an artist with the insight of a scientist (he is an aquatic ecologist and college professor by background). From this book I learned a great deal about what makes a lake tick -- explained in ways that I am sure his students at Minnesota's Anoka-Ramsey Community college much appreciated. Consider phosphorus and its effect on algae in lakes. Nelson first describes all the ingredients in his wife Geri's blueberry muffins and explains how, if she happens to have only two teaspoons of baking powder, she can only make one batch of muffins -- no matter how much flour and sugar and how many eggs she may have on hand. Then:

"...(I)n lakes, except in unique circumstances, the 'tin' of phosphorus usually empties first. Compared to demand, it is phosphorus that is available in least supply, the bottleneck to alchemy. Little phosphorus in lake water begets few cyanobacteria, algae and aquatic plants. Lots of phosphorus begets lots of blue-green (algae) or aquatic plants or both."

If there's a better description of the effect of phosphorus on lakes, you've got to show me. If our Wisconsin legislators -- and their constituents -- could read those simple words, they might understand this phenomenon better and we might have less squabbling over whether we really need to spend so much money to keep phosphorus out of the water.

I also learned about the geological history of the lakes of the Upper Midwest and the glaciers that formed them. Through Nelson's descriptions, I could almost see in my mind's eye a time-lapse movie of the glaciers advancing and receding across the landscape, and hear the crunching of rock and the flowing of glacial melt water.

Perhaps even better than all that was Nelson's sheer joy and awe at seemingly ordinary events like observing the tiny water fleas and other creatures in a jar of lake water, or snorkeling thought weed beds on his favorite lakes and seeing sunfish stare right at him through his mask. And one can't help but notice Nelson's passion for protecting our lakes -- a passion he lived out by serving three terms in the Minnesota state legislature and advocating all sorts of conservation-oriented legislation.

Nelson's 250-page journey takes us on visits to dozens of lakes he has known and loved, from Henry David Thoreau's Walden Pond to the "ghost" Lake Agassiz, which once extended north from the Minnesota-South Dakota border area for hundreds of miles into Saskatchewan and Ontario. It is a fascinating journey that, if you take it, will deepen by many fathoms your appreciation for lakes in general and for the special lakes you love. It will also will inspire and motivate you to do your share to protect them -- and fight for their protection in the public arena. It is hard to consider an ecological education complete without having read this book.

Canoe Reconnaissance

This is our first spring as regular visitors to Birch Lake. This weekend I kept a promise to myself and canoed the entire perimeter, splitting the trip into two days, two hours at a time. Luckily the weekend was calm, so it was easy to paddle at a relaxed pace along the shoreline.

Have you canoed your lake in spring? It’s a good time for a couple of reasons: There are no motorboat wakes to contend with, and the water is clearer before the sun and warmer temperatures have a chance to feed the algae. I would have liked to take a Secchi disc reading; I am sure it would have shown better light penetration than in summer.

Having no water-testing equipment, I just cruised along shore, a gentle paddle stroke at a time, eyes down on the water on the shoreward side – I’m a fisherman and so always want to see what’s active. What I saw bodes well for opening day two weeks from now. Numerous smallmouth bass were in the rocky shallows and under logs. Walleyes (identified by the white tail spot) haunted the woodpiles – in one case at least a dozen of them, in an assortment of sizes, some clearly in the keeper range.

In a back bay I found a substantial school of perch that, while still small, had made it past the fry stage and so have boosted their odds of survival to adulthood. One reed bed held a cluster of crappies. Here and there a northern pike or small musky hung suspended over gravel and sand bottom. One large musky cruised under the canoe. The lake’s many painted turtles were in evidence, some swimming underwater, others sunning on logs (until my quiet approach sent the plopping to safety). It was disappointing, though not surprising, to see a few rusty crayfish skittering tail-first across the bottom.

You learn things every time you look closely at a lake. I believe I found a few new fishing spots – that walleye-populated woodpile being one – and discovered why certain other places that look good in summer in fact are not (too shallow, bottom too mucky). It was a pleasant way to get to know “our” lake better and to get ready for fishing season. I also met a few lake neighbors, putting in their piers or sprucing up their waterfronts. Piers are back in place at most of the cottages and pontoon boats are in the water.

I would definitely recommend a slow canoe or rowboat ride around your lake before the weather warms up and the water gets busy. What you see will open your eyes to a world that’s bigger and more interesting than you realize.

Putting In the Pier

I am not a lover of chores, but there's one I truly enjoy, and that's installing the pier at our Birch Lake cabin. That's partly because of all that the job portends: a seemingly endless spring, summer and autumn, filled with fishing, swimming, sunset watching, visits from friends and family. Perhaps that makes the sheer mechanics of it, enjoyable in themselves, all the more so.

The first time we put the pier in, three years ago, it was a bit of a project. The whole thing was new, and my son and I had to figure out how to assemble the various components, notably the main supports. That meant screwing baseplates onto the posts, sliding the crosspieces on, and setting them in position. Then there was the matter of bolting on the rails that would hold the cedar boards, and getting everything meticulously square and level. Now that we have the main supports assembled, it's just a question each spring of moving them into position and bolting the rails on. Because I put the supports back in the same order each year, only a modest amount of leveling is required.

I put the pier in this year the Saturday before Easter, which was April 7. It took all of an hour and 15 minutes, start to finish. Square, level, crescent wrench, 5/16-inch socket wrench -- that's it. Eighteen nuts to thread onto bolts and tighten down. Carrying the cedar boards from under the screen porch down the steep slope to our waterfront was a bit tiring, but the pier is only 40 feet long, so at two 2-foot sections per trip, that's 10 times up and down. I spread that out over two days, and so it wasn't taxing.

Now the pier is in place. I bring my boat to the lake on opening day of fishing season, Saturday, May 5. A pleasant chore is done and done well. A long open-water season lies ahead.

Waiting for ice-out

Friends Steve and Mary Jo visited our Birch Lake retreat last week. Steve and I went ice fishing – he showed me the routine of setting tipups for walleyes. It was single-digits cold with wind gusts to 25 mph and more, blowing new snow in miniature tornadoes across the lake. Boring holes with the gasoline-power auger, we found the ice 18 inches thick.

Now February is winding down, and I’m waiting for ice-out. I’ll be waiting for a while, I realize, but I look forward to observing, for the first time ever, the thawing of a lake. I never had that opportunity until we bought our land and had year-round access to the lake. I do know that lake-dwellers keep track of ice-in and ice-out dates as major milestones of each year.

While I wasn’t there to see it, I know that the ice went out early on Birch in 2010. I waded in the lake, not at all uncomfortably, in mid-April of that year. 2011 was a different story. When our family held a ceremonial groundbreaking for the cabin on April 16, the lake was still frozen stiff, it was cold, windy and snowing, and we drank our champagne huddled inside our RV trailer.

This year all signs point to early ice-out, but of course that can change – March can still be brutal and April chilly, and the ice can linger even into May. Now that the cabin is complete, we can be there as the days finally get warm and the ice recedes. I can’t wait to watch it happen.

This wonder we call water

Early this week my wife and I took the springer spaniel, Freckles, for a walk from our Birch Lake cabin. We hiked down our private road, along a short section of snowmobile trail, and then onto the lake. Here Noelle hesitated; she had never skated or walked on a frozen lake before. Freckles had no such trepidation and tugged hard at the leash. We followed, taking an arcing path across the ice to where our pier would be in summer.

Isn’t it wondrous that we can walk on the lakes in winter, and that the water below teems with life forms, active and dormant? We owe it all to a singular property of water. Most liquids contract as they cool and keep on contracting until they solidify. Water, on the other hand, contracts until it reaches 4 degrees Celsius (39 degrees Fahrenheit), at which point it begins to expand, and continues to expand until it becomes ice. So as a lake cools down toward the freezing point (zero Celsius, 32 Fahrenheit), the densest water at 4 degrees Celsius is at the bottom. Ice forms at the surface and, because it is less dense than the water, it floats. Soon a skin of ice covers the lake, and it gets thicker with cold days and nights as winter deepens. This ice then insulates against the subzero temperatures and keeps the water below in the liquid state, in which life thrives.

Why water behaves this way is a matter of chemistry and physics – of molecular vibration, positive and negative charges, molecular shapes, hydrogen bonds and such. I don’t claim to understand it all. I do marvel at how earth’s most abundant substance – the one life depends on, the one life is made of – shows this benevolent anomaly of expanding, not shrinking, as it cools toward freezing. What if this were not so? Ice crystals forming on the surface would sink. As more and more water froze, would it begin collecting on the bottom? And would our lakes continue to freeze all winter, until they froze solid?

When walking on a frozen lake, or drilling through the ice and lowering golden shiner minnows from tip-ups to catch winter walleyes, it is wondrous to contemplate the special properties of water.

Rusty crayfish: An invasive menace

While walking on frozen Birch Lake recently I saw something I had never seen before. An ice angler ran to a tip-up displaying a flag and pulled up not a walleye but a crayfish. It was a rusty crayfish, a species native to the Ohio River valley that anglers brought to Wisconsin as bait and that has taken over a goodly number of lakes.

I thought crayfish just lay dormant all winter, but apparently not. At any rate, the rusties overran Birch Lake about 15 years ago, wiping out its rich cabbage weed beds and changing the whole structure of the fish population. Panfish and perch are all but gone, although walleyes are abundant and smallmouth bass reach genuine trophy size.

A trapping program run by the Friends of Birch Lake group has helped bring the crayfish population under control. So has increasing predation by fish and, at least according to rumor, so has a viral disease. Still, it’s upsetting to see such profound change brought on by a species that does not belong in the lake.

Invasive species – fish, plant, invertebrate – threaten many inland lakes, maybe including yours. If you want to learn about just how rusty crayfish can affect a lake, you can read my 2008 story from Wisconsin Natural Resources magazine at http://dnr.wi.gov/wnrmag/html/stories/2008/oct08/crayfish.htm.

What type is your lake?

Your lake is different from every other, of course – no two are alike, even in a place of many lakes like Wisconsin, where I live, or Minnesota. Still, it’s possible to place lakes into categories, and there are various ways to do it – by the way they were formed, by their level of nutrients, and by how they get their water, to name a few. Let’s start with this last classification.

The number of lake types based on source of water depends partly on who is doing the defining. The Wisconsin Department of Natural Resources lists four types, but there is a fifth that many geologists mention. Here are five basic lake types commonly found in Northern Wisconsin and Upper Michigan:

Drainage lakes. On these lakes, a stream brings water in, and a stream takes water out. That is, the lake has an inlet and an outlet – and in some cases more than one of each. The water level in these lakes tends to stay fairly constant – think of a bowl into which you run a slow flow of water from the tap. (Lakes created by a dams fit the descrption of drainage lakes, although they are usually classified as impoundments). 

Spring lakes. These lakes have no inlet on the surface, but they do have an outlet. They get their water mainly from groundwater flowing in. Many streams originate in spring lakes, which are quite common in northern Wisconsin.

Drained lakes. These lakes are like spring lakes in that they have an outlet but no surface inlet. They differ in that they are not fed by groundwater – they get their water almost solely from precipitation and runoff. For that reason, their levels can fluctuate: high in rainy times, low during droughts. During long dry spells, the streams flowing out of these lakes may dry up. Drained lakes are the least common type in northern Wisconsin.

Seepage lakes. These lakes have no stream flowing in or out. Their water comes mainly from rainfall and runoff, sometimes supplemented by groundwater. Their water levels are therefore cyclical.

Perched lakes. These lakes are truly landlocked. They have no inlet, no outlet, and no contribution from groundwater. In fact they sit on relatively high ground, above the water table, with a dense bottom sediments that hold the water in. Water levels in perched lakes can drop dramatically during long dry spells.

Which type is your favorite lake? If you don’t already know, consider doing some investigating to find out.

How We Met: Birch Lake

My memories of summer vacations on Duck Lake in the Upper Peninsula stayed with me and ran deep. And so I wanted to create a similar tradition with my own family, wife Noelle and kids Sonya and Todd. We tried week-long vacations at cabin resorts on Moon Lake (Duck’s neighbor in the UP) and Presque Isle Lake in far northern Vilas County, Wis. But I was looking for a place we could return to year after year, and for various reasons neither of those two quite fit.

The next year, in 1987, when Sonya was five and Todd two, we wrote to the Oneida County Chamber of Commerce for information on housekeeping cabins. Dozens of brochures came by mail; the one that appealed most was for Jung’s Birch Lake Cottages, near a place called Harshaw that we had never heard of, about a dozen miles southeast of Minocqua. We bought a week in a cabin called Bayside, sight unseen, for $400 (enough money back then to ensure, pretty well, a quality experience).

It was love at first sight. Noelle fell for the cozy two-bedroom cabin, with new furnishings, knotty pine walls and, as bonuses, a fireplace, microwave oven, and deck – in her words, “all the comforts we don’t have at home.” For me it was about the lake, 180 acres with expansive beds of cabbage weeds on the edges of which I could catch walleyes, bluegills, perch, and the occasional largemouth bass. The romance was sealed when, on our first night, I caught a 38-inch muskie right off our pier. There was a nice swimming area for the kids, and all the Northwoods icons were there -- loons, ospreys, eagles, deer, raccoons.

We visited Birch Lake for a week almost every summer thereafter, usually staying in the Lakeside cabin, right next to Bayview. Then in 2009, a wooded lot came on the market, straight across the lake from the cottages. We closed on the lot in December of that year, parked an RV trailer there, and by fall 2011 had our own cottage. The way we came to buy the land is a story in itself, for another time. Suffice it to say our relationship with Birch Lake has bloomed into something deeper and longer-lasting.

How about you? How did the romance with your favorite lake begin? How did you two meet?

How We Met: Dinner Lake

Dinner Lake, my second love, lies in Michigan’s Upper Peninsula about three miles over the treetops from Duck Lake. I discovered it on a side trip from the Duck Lake cottage, just a random exploration for more places to fish. I was about 24 then and feeling a little constrained just fishing one lake. I had no boat, but at the time that didn’t matter.

I just headed north on Highway 45 from Land O’Lakes, saw a plain wooden “Dinner Lake” sign at the first side road, took a right in the direction of the arrow, and followed the signs from there. The roads twisted back into the trees, first nice smooth asphalt, then much rougher asphalt, and then a skinny, bumpy gravel road for the last quarter-mile or so. The road dipped sharply down and bent around to the right, revealing the lake, a small blue jewel in a wooded hollow. Logs lay in the water on both sides of the boat ramp, and among them small bass hung motionless. I broke a piece off a twig and tossed it onto the water; a fish darted up, took it, and spat it out.

The boat ramp was on an almost circular bay, a narrow outlet giving way to the lake proper. I couldn’t see much of the lake itself, but several bare logs jutted out from the bay’s shore – great-looking cover. I hung around for a few minutes teasing the baby bass with bits of twig, then drove away, filing the spot in memory.

The next summer I bought a used blue fiberglass canoe. On a June weekend my friend Ed and I strapped it atop my 1964 Plymouth Valiant and drove north. We tented at the National Forest campground on Lac Vieux Desert and in the morning drove over to Dinner and slid the canoe in. We immediately found smallmouth bass among the logs, more than willing to smack a floating plug. As it turned out, loggy cover nearly surrounded the lake. We caught dozens of bass, about half of them above what was then the legal size of 12 inches.

I’ve returned almost every year since, with friends or alone. In time I discovered a rocky hump just off the east shore that is productive even when fish have deserted the shoreline cover. It’s a quiet lake, about 150 acres, ringed by small, well-kept cottages, most occupied just sporadically. I’ve never been able to spend an evening or weekend on the lake. In the early years there was a private campground on the east shore, but that soon closed. So it’s a lake I simply fish, once a year (with rare exceptions), almost as a matter of principle. After all, I discovered it. I don’t tell many people about it. My stock comment about it is: I’ll take you there, but I won’t just tell you where it is.

How about you? Where did your romance with your favorite lake begin? How did you two meet?

The Otter in Winter

Before the snow got too deep for easy walking, I took Freckles (our springer spaniel) for a daily winter hike on the ice of Birch Lake, near Harshaw, Wis., where we built a cottage last summer. One day we came upon the track of an otter following the very edge of the ice. The clawed paw prints and the belly imprint (or was it a tail drag?) in the snow made clear whose track we were following. Freckles did not seem to find a scent, so the trail must have been cold. We followed the trail along the shoreline, then across a bay, to where it led into the trees. Backtracking a long distance, we found a 6-inch hole in the ice near the marshy spot where a creek exits the lake. The snow on the shore near the hole was littered with scat.

I had seen otters (technically river otters) in the wild before, but never on Birch Lake, and I had never felt quite so close to one, although the animal was not present. Otters remain active in winter. Where they can find openings in the ice, they will enter the water to hunt for fish, clams and other prey. This otter clearly had made its own hole (the ice next to shore was thin). Otters can remain submerged for long spells and can breathe in the space (if it exists) between the ice and the water. I'll be keeping my eyes open for otters on the lake this winter, and maybe I'll be lucky enough to spot one while taking a snowshoe walk toward evening or on a moonlit night. I’m glad to know they live here on the lake we now call home.

One lake, many worlds

It’s easy to think of a lake as a pool of water in which to drop a fishing lure or on which to float a boat, canoe or air mattress. But your lake is really a collection of worlds, each in its own way teeming with life. There’s the water’s edge where otters prowl the sandy fringes, where deer slip out from the cover of the trees to drink, and where eagles and ospreys perch in tall pines and scan the wavelets. The air above the water is another world, of those big raptors soaring and circling; f buzzing dragonflies, silent and delicate damselflies, and flying insects of many descriptions; of mallards and mergansers arrowing overhead.

On the surface we find ducks and loons skimming; the occasional muskrat dragging strands of cattail leaves; clusters of darting black beetles; water striders floating on surface tension, propelled by oarlike legs; ephemeral mayflies with wings raised like sails; and painted and snapping turtles, snouts poking skyward, sipping the air. Beneath the surface the lake is a thin soup of microscopic plant and animal plankton, base of the food chain for fish, not just those we like to catch but for many small and secretive species we rarely see, even if we peer into their world through a glass mask while snorkeling.

The bottom sand and muck are marked with the serpentine trails of clams and mussels and speckled with the curled shells of snails and the molts of crayfish. Buried in the sediment lie an assortment of worms, along with immature forms of various flies and other insects, metamorphosing. And that’s not even counting the different zones of vegetation; the variations in bottom character (rock, gravel, sand, muck); the dropoffs, flats and mid-lake humps; or the temperature-related strata of the water itself. Or, for that matter, the way these and all the other worlds change with the seasons.

Yes, every lake is much more than what appears to the casual viewer. And every lake rewards those who look closer and deeper.

How We Met: Duck Lake

Every romance story starts with how they met. How did your romance with your lake begin? My story begins with Duck Lake – I have known it since I was eight years old. It lies in the big woods of Michigan's Upper Peninsula, just over Wisconsin line from the little town of Land O' Lakes. It’s about two miles long, shaped something like a plump L with a short horizontal stroke.

A co-worker of my father owned a cabin on Duck Lake. He and his two sons took my dad, my older brother and me there for a visit on a Memorial Day weekend. It was there I saw eagles and loons for the first time, and heard the hammering of pileated woodpeckers deep in the forest. How to describe the allure of the North? The trees are taller, the white pines especially standing in majesty. The wind sounds different. Storms loom larger; thunder booms across the vast stretches of woods and water. The night woods are full of animal noises, rustles and footfalls. Loon calls ring out over the lake – what benignly demented sort of deity would create such a creature as a loon?

My family rented that cabin one or two weeks each summer until I was in my early 20s. A great fishing spot lay just a few dozen oar strokes out from the cabin. We fished there morning to dusk, two or three of us kids in each boat with mom or dad. As I grew older, I took a 14-foot wooden rowboat on fishing explorations from one end of the lake to the other. Since then I’ve fished Duck once or twice a year almost without fail and have come to know it well. The public boat landing is right next to the old cabin property; that spot in front of the cabin is still the best spot on the lake.

In future posts I’ll tell you about my other two loves, Dinner and Birch lakes. Meantime, what’s the story of your favorite lake? How did you two meet?

Growing to love your lake

I have three mistresses. My wife not only knows but approves. The mistresses are Wisconsin northwoods lakes, two just far enough north and one just far enough south to be spared most of the tourist noise. I've carried on affairs with each for at least 25 years, in one case for more than 50. Their names are Duck, Dinner, and Birch. My relationships with them are somewhat one-dimensional: Mostly I fish them. And yet, through the years, I weigh each visit less in fish caught than in ambience, comfort, memory. I promise not to stretch the romance metaphor too thin, but I do love these waters.

You may have a  favorite lake, or more than one -- a place where you vacationed as a child, where your family owns a cabin, where you rent a summer cottage year after year, where you go on a ritual long-weekend camping trip with friends. It's easy to love a lake, especially one you found on your own fairly early in life and have known for decades. What is love, after all, but genuine concern for someone or something outside ourselves?

What I hope to do here is help you love your lake even more -- by getting to know it intimately, as I have come to know mine. I've finally chosen one lake -- my wife and I have built a cottage there that one day may become a home. So I'll share with you what I observe about my lake and what I've learned about lakes in general, through experience, observation, reading, and even lab, field and classroom study. In the process, because for all their differences lakes have much in common, you will learn more about your lake and come to appreciate it more.