Sunday, September 22, 2013

Overnight low: 31 F

This time of year we start seeing boats put into storage, piers pulled out, cottage piping drained and windows shuttered. And yet it’s possibly the most beautiful time to be out on your lake. Not swimming in it, mind you, but on it or looking out over it.

This time of year, we see outdoor enthusiasts packing the fishing gear away and pulling out the shotguns, the grouse guns, the deer rifles. Yet it’s still a great time for fishing. A sense of urgency pervades the underwater world. Muskies, walleyes and bass are feeding heavily for the winter. It’s the time of big baits for big appetites. Last week on Birch Lake near Harshaw, Wisconsin, where I live, I caught a 7-inch smallmouth bass on a 5-inch walleye sucker minnow. Imagine what the muskies are eating.

I ignored this morning’s near-freezing temperature and went fishing for a while, parking the boat above a favorite rock bar. The 20-inch smallmouth I caught wasn’t the highlight – that was the general sense of urgency to be felt all around. Urgency for me because the remaining fishing days are few (and I am not a hunter). And urgency for the wild things. I saw ducks stopping by on their migrations. Seagulls swooping down to pluck something or other from the water. And above, a vee of geese. I heard their calls but had to scan the sky to locate them, very high, straight over my head, against cottony clouds.

There’s a narrow window between now and winter, a window quickly closing. Within two weeks, maybe three, the leaves will flare, fade to brown, and blow away. The air's crispness will give way to bite, and November's winds will turn vicious.


So now is the time to be with your lake. Pick a warm autumn day and take a long, slow boat ride. Soak some minnows in a favorite fishing spot. Take a cup of coffee or hot cider,  sit on the pier bench you will soon take down, scan the shorelines and enjoy the colors of the trees reflected in still water. Enjoy the lake while you can. Make a few more memories. Winter’s on the way, and winters here are long.

Friday, September 20, 2013

The air down there

I once told friends how a fishing pal and I spent an August morning catching bluegills in 60 feet of water on a lake in Waukesha County, Wis. The fact is we were floating in a boat above water 60 feet deep, but there was no way the bluegills were down there on the bottom. What happened was that bluegills suspended about 15 feet down were catching our baits as they fell. We only thought we were pulling them out of the depths.

How do I now know this is true? Because there was no way those bluegills could have lived that deep under the surface. And why? Because there was no air down there – or more properly, not enough oxygen.

In a previous post I wrote about how lakes thermally stratify in summer – a layer of lighter, warm water on top, and a layer of denser, cold water below. The difference in density is enough so that the two layers don’t mix very much. And as a result the lower, cold layer becomes very deficient in oxygen, more and more so as summer wears on. That upper layer (called the epilimnion) gets recharged with oxygen daily and the wind kicks up waves, or just through normal diffusion. The lower layer (the hypolimnion), of course has no access to the surface, so no way of getting recharges, and meanwhile its oxygen gets steadily used up.

Algae, dead plant matter, dead fish, and all manner of organic material sink to the bottom throughout the summer. There, it is broken down by aerobic bacteria – the kind that need oxygen to live. Gradually, the amount of oxygen dissolved in the water decreases, until there is too little to support fish or much of any kind of life. The depletion may become so extreme that the job of breaking down dead matter falls to anaerobic bacteria, which exist without oxygen. So that zone toward the bottom of the lake becomes almost a dead zone – a hostile place.

This is one reason why summer anglers are cautioned not to “fish too deep.” If you drop a bait beyond the upper, oxygen-charged layer, into the lower, oxygen-poor zone, you might as well be fishing on the moon. There’s a thin zone between the two layers (sort of like the thin layer of peanut butter in a sandwich) where the temperature changes rapidly, from warm to cool. This is called the thermocline, and fish will stay at or above it – they have no choice. The bluegills my pal and I were catching that August day in all likelihood were sitting at the thermocline.

Of course, lakes do not remain stratified. At this time of year, as the days and nights cool, so does that surface water. The epilimnion gets steadily cooler and thinner, until finally the whole lake temperature equalizes, at which point the wind can stir things up, adding life-giving oxygen throughout. This is called the fall turnover. You can actually see this happen on your lake as the water all of a sudden becomes cloudy, as the dirtier water from below mixes with the cleaner water from above. You might even notice a hint of sulfurous smell – the result of hydrogen sulfide (“marsh gas”) produced by those anaerobic bacteria in the depths as they fed on dead material through the late summer.

The turnover on our lakes here in northern Wisconsin is happening about now. It’s a rite of autumn, as inevitable as the oaks and maples turning color.

Saturday, September 14, 2013

Is everyone a fisheries expert?

Are you satisfied with the fishing on your lake? Is it as good as it used to be? Is there talk about a need to stock more fish? Or change bag and size limits?

Many lake associations and friends groups want to improve the fishing, and that is certainly the case here on Birch Lake, near Harshaw, Wis., where I live. Here, the fishing most certainly is not what it used to be. Years ago, this was, in the words of one long-time cottage owner, a “dummy lake,” meaning any dummy could catch fish. Bluegills and crappies abounded. Perch could be caught at will. Walleyes grew to trophy sizes. Largemouth bass and northern pike were available, as were muskies.

Then about a dozen years ago, rusty crayfish invaded and mowed down the cabbage weed beds that created much of the fish habitat. Fishing was bleak for a few years until the lake Friends group began trapping the crayfish, smallmouth bass moved in, and they and other fish began feeding on the invaders. Now we have trophy smallmouths, abundant walleyes, (though on the small side), and a good musky population, but panfish are about nonexistent. People long for the old days, as do I, since my family vacationed here for about 20 years and we saw the before and after of the crayfish explosion.

At meetings of Friends of Birch Lake, someone almost inevitably brings up the fishery and how we can improve it. The group has placed a couple dozen cribs in recent years, five last year alone. Some members want to petition the DNR for a special walleye regulation that would let us keep fish below the statewide legal size limit of 15 inches. Others want the DNR to stock fish here. The latest idea to surface, in the newsletter of the Friends group (of which I am treasurer), is to have people start keeping (instead of catching and releasing) smallmouth bass. The thought is: The bass are abundant and we need to “balance the species.”

Now, this informal fishery management practice has no scientific foundation – no lake survey, no assessment by an aquatic biologist. I am fully sensitive to the concern about the lake and its fishery. I’ve had ideas of my own on how to improve things. But I must admit my ideas have no more scientific merit than anyone else’s, so I have largely kept them quiet. I might suggest that, if we can afford it, our Friends group commission a lake study by an independent biologist. Then we might know where the fishery stands and be able to propose changes that have a reasonable chance of success.

In the meantime, I am going to release smallmouth bass – anything that eats rusty crayfish is my friend. In fact, I imagine most other anglers feel the same. Anyway, the catch-and-release ethic is strong, and most would be about as likely to start keeping bass as to quit brushing their teeth.

The point is that we all care about our lakes and the fisheries, and we’re all willing to invest time and to some extent money to make them better – but we need to build our actions on a foundation of knowledge. If we do just a little research, we find that stocking fish is rarely a long-term solution. Lakes prove out Aldo Leopold’s findings about carrying capacity: It’s habitat that decides which fish species thrive and in what numbers and sizes. We also find that usually cribs do more to concentrate fish already there than to expand their populations. And we find that tinkering with size and bag limits and changing the catch-and-release ethic are at best exercises in guesswork, unless we know through research what we’re doing.

So if we care as deeply about our lakes as we claim to, perhaps we need to put our money where our passions are and learn what’s happening under the water before we start trying to change things to suit our wishes.



Tuesday, September 10, 2013

What’s the rush?



I call them “pencil reeds.” That’s because they grow sticking straight up out of the water like, well, pencils. When I was a kid, my dad called them reeds. On the lake where we vacationed, he would row us through a patch of them and let each of us pluck one to trail in the water.

I now know they aren’t reeds at all, but rushes. I also know they hold fish. If I’m fishing on an unfamiliar lake and see “pencil reeds” along a stretch of shoreline, or better yet, away from shore, that’s a place I’m going to try. They grow in shallow water, but bass, panfish and sometimes northern pike haunt them regularly.

Hardstem and softstem bulrushes are common here in northern Wisconsin, and in fact there’s a bed of what I believe to be hardstem right next to our pier. In fact, by mid- summer, they grow up between the pier boards and I need to give them a haircut. Some people along our shoreline have dug the rushes out to expose the sand bottom for swimming.  I’ve mainly left them along because of the shelter they provide for young fish; I often see schools of perch and smallmouth bass fry in “our” rush beds.

These rush beds typically aren’t too dense, so when fishing one is tempted to cast a lure deep into them to tempt a big fish holding in the cover. When I try it, I usually regret it. On the retrieve a treble hook is all but sure to snag a rush, and it’s difficult to pull it out of the tough, fibrous stalk. That means paddling or trolling-motoring over to extract the lure by hand.


Do  “pencil reeds” grow on your lake? If so, test them for their fish-holding potential. And note that snorkeling through them or along a bed’s edges can bring you lots of fish sightings.

Tuesday, September 3, 2013

How clear is your lake?

Is you lake clearer than the next one over? Clearer than the one where your best friends live? Maybe the questions don’t matter to you, but water clarity is one attribute people think of when judging the quality of a lake. So how do you find out whose lake is clearer? You could get a qualitative judgment by slipping on fins, a mask and a snorkel and kicking your way around both for a while, eyes down. Or you could get hold of an electronic turbidity meter and scan a test-tube sample taken from each lake.

Of course, there’s a middle ground, and that’s to make yourself a Secchi disk. It’s a very simple tool for measuring lake water clarity with reasonable accuracy, and it’s really quite a bit of fun to use. Secchi disks (pronounced SEKK-ee) are accurate enough so that freshwater biologists often use them for their water clarity measurements. Look at a Department of Natural Resources report on fish stocking for a lake and you’re likely to find a Secchi disk reading.

A Secchi disk is simply a circular, plate-like object on a rope that’s painted with quadrants, like a pie cut in four pieces. Two quadrants are white, the other two black. To use the disk, you go out in a boat to where the water is deep, then lower the disk slowly, slowly, until you can no longer see it. Mark the rope at the waterline. Then slowly, slowly, pull the disk up until you can see it again. Once more, mark the rope at the waterline. Now retrieve the disk and measure the distance from the disk to both marks. Take the average, and that’s your Secchi disk reading.

What the Secchi disk actually measures is how deep light penetrates into the water. Suppose your Secchi disk disappears at 10 feet below the surface. How deep does the light penetrate? That's easy, right? Ten feet. Ah, but no! The light you see bouncing back from the disk actually has to make a round trip, from the surface and back up to your eyes. So a Secchi reading of 10 feet means light penetrates to a depth of about 20 feet. 

A Secchi disk is quite easy to make. On the Internet, you can easily search up instructions on how to make a one good enough that a biologist would be happy to use it. Since you don’t need one good enough to sell in a scientific supply catalog, all you really need is a round object, a weight to make it sink, a drill to bore a hole in it, a length of rope, and a couple of cans of paint (ideally waterproof).

As long as you can get the disk to stay face up as you lower it, it’s good enough for your purposes. Try making one and checking your lake water clarity – not just once but at different times of year, including winter, through the ice. Keep a record of Secchi disk readings in your home or cabin log. You’ll enjoy it, and chances are the kids will love it.



Sunday, September 1, 2013

In the middle of nowhere

I often hear lake home and cottage owners say, “My lake is no good for fishing.” In fact, I heard such a person say that about an Upper Peninsula Michigan lake that is my all-time favorite and rarely if ever lets me down. Maybe people who say that are just using the old angler’s trick of keeping the mouth shut about a good spot. Or maybe they haven’t discovered the magic of something called the mid-lake hump.

Serious fisherman know about humps, of course. They’re also known as bars, reefs, or sunken islands. Call them what you will, they hold fish. If you see a boat parked out on your lake, away from shore, seemingly in the middle of nowhere, chances are that angler is working a hump. Novice fishermen, and even long-timers who never got serious, tend to fish along the shore, in the lily pads, around piers, or in fallen timber. Wisconsin guide and lure-maker Joe Bucher calls that tactic “bank beating.”

You can find fish in the shallows, of course, especially at early-season spawning time. But more often you’ll find more and bigger fish around deeper-water features, and one such feature is the mid-lake hump. How do you find humps? The easiest way to start is to buy a topographic map of your lake that shows the depths. That will give you the approximate locations of spots to try. If no map of your lake exists, then you have to go exploring. One good place to look is in an area well away from shore where you’ve seen people fishing.

With or without a map, you can pinpoint humps by prowling around slowly with your depth finder (fish locator) running. Before I owned one of those devices, I would find humps by rowing or motoring slowly with the anchor hanging down about 15 or 20 feet. When it hits a hump, you’ll know.

How do you fish a hump? It’s not difficult. You fish pretty much the way you would in a near-shore area. If the hump is shallow (say, five or six feet), you can cast spinners. If a little deeper (maybe 10 to 12 feet), throw deep-running crankbaits. Or in either case, you can hop jigs along the bottom, or cast slip-bobber rigs.

How good are humps? So good that once you know about them, you may give up “bank beating” for good. Just last month, on a small lake near our home (no, I’m not telling which one), I worked a hump I’ve known about for some 25 years. This hump, about 100 yards from the nearest shore, rises from 20 feet of water up to seven feet.

While people in three other boats worked the wood along shore, I anchored on the hump and cast leeches on a slip-bobber rig. In about three hours, I caught 12 smallmouth bass, plus 10 walleyes – eight of them easily legal size, and two of them well over 20 inches. I released all the bass and kept three of the smaller walleyes, which are now in my freezer awaiting a special occasion.

If you’ve been mostly a “bank beater” on your lake, try taking a day to find yourself a mid-lake hump. Once you do, you have a great place to take your kids. And you might never again have cause to say, “My lake is no good for fishing.”