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.