What the ice reveals

Ice mostly obscures a lake, especially once snow falls on top of it. There's about eight inches of snow on Birch Lake now, not quite enough for snowshoes (at that depth it's easier walking without them than with). I enjoy near-daily walks along the lake perimeter with Freckles, our springer spaniel. One morning I left him at home (to his considerable protest) and walked all the way around the 180-acre lake by myself, talking no shortcuts, following the shoreline of every bay and inlet. It took about 90 minutes, and that's a good workout when one is wearing pack boots and shuffling through snow.

One thing I didn't do that day was follow Seed Creek, which flows out of Birch Lake and winds its way through a swampy woods to little Seed Lake. In liquid-water seasons I had tried taking a canoe down the creek, just to see how far I could go, hoping ultimately to reach the lake and find a secret back-in fishing ground. As it turned out, I coundn't go far, because although the water was deep enough to float the canoe, the creek was barely 10 feet wide, skinnier than that in many places, and tree branches and logs blocked the way. Now, in January, I thought maybe I could walk the creek ice to Seed Lake.

So I took Freckles out on his leash, and we walked the half-mile or so from our frontage to the creek outlet and started downstream into the woods. The creek flows slowly and so had frozen over reasonably solid. Animal tracks criss-crossed the snow -- some obvious deer hoof prints, once in a while the stitchings of a mouse, here the belly-drag of an otter, in other places markings I couldn't identify (footfalls in powder snow don't leave the well-defined tracks one finds in mud or soft sand).

We strolled along, around bend after bend; now and then I had to push aside branches that Freckles slipped neatly beneath, The ice often creaked under me; I wasn't too concerned because I knew from my canoe foray that if it gave way, the water probably wouldn't go past my boot tops. Deeper into the woods we wandered, stopping now and then to listen to the silence, staying still sometimes just long enough to hear the circle of life start closing in around us, chickadees appearing deep in the trees.

Then we reached a stretch where the ice looked unstable -- barren of snow, lumpy and translucent. There being no easy "portage" around this section (the brush on both sides was thick), I decided to turn for home. Not long after we started back, Freckles broke through. He quickly sloshed out and back up onto the ice, the water having just wet his belly fur. What I wondered was: Why had the ice held my 240 pounds but not my 45-pound dog? He must have simply found a weak spot. I headed directly back to the cabin to get Freckles to a warm place.

So we never made it to Seed Lake, and the creek's course is so twisted I don't even have a good idea how close we came. We did enjoy a visit to a tranquil place I am sure few others ever see, a place of tall, bare trees towering over scrubby brushland, of deep silence, of mystery, a place that wouldn't have been revealed to us if not for winter's ice. Perhaps a few subzero days will freeze the creek harder and allow my walking partner and me to complete the trek to Seed Lake.

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.