Urban Fly Fishing: Smallmouth bass in the Mississippi

I had a few hours free after class today, so I decided to take advantage of the nice weather and fish. I walked the mile to the Mississippi and worked my way down the steep bluff to the river's edge.

In my several attempts to fish here in the last few years I haven't caught anything, but I have seen a few jumps, so I know they're around. Most of the shoreline is shallow and sandy, but I found a spot where the outflow of a storm drain leaves a culvert perched just above water level. The water leaving the culvert has dug out a deep hole that I knew just had to hold fish.

I worked a black wooly bugger through the deep section without a bump, so I decided that I might as well practice casting. I aimed at the spot where water from the culvert meets the surface. I stripped the fly in once, then felt a strong pull.There was a flash at the end of my line, then the fish dove deep into the murky water, taking line as it went. After a strong fight I landed a nicely sized smallmouth.

Three others followed in the remaining hour I spent fishing. I still prefer trout to bass, but it was fun catching some nice fish in a cool spot. Plus, you can't beat fishing a mile from home.

Weather and Trout

Most anglers agree that weather has an impact on trout fishing, What they tend not to agree on is how weather impacts trout fishing. Weather is complex and difficult to predict, as is trout behavior, but I’ll try to be as scientific as possible in this post.

Water Temperature

Water temperature is likely the most important environmental influence on trout behavior. For a good description of the ways water temperature affects trout, check out this blog post: Link, but for this discussion all you need to know is that trout feed most actively between 40-65 F and begin to suffer potentially lethal stress at 70 F.

So, how does weather affect water temperature?

Several factors come into play. The first, and most obvious, is air temperature. Air that is warmer than the water will warm it and air that is colder than the water will cool it. But air temperature is not the most important factor.

The transfer of heat between air and water is slow and can only take place at the waters surface. Sunlight plays a larger role in warming the water in streams, as it directly warms the water and stream bottom. This is why shade is vital to keep water temperatures below lethal levels in trout streams in warmer climates.

When planning a outing, it’s important to pay attention to both air temperature and sunlight. In winter, when water temperatures are cold, a sunny day can give trout the boost they need to feed. Daytime air temperature is less important than sun in winter, but it can pay to check the low temperature for the day before. Although warmer high temperatures are generally better for fishing, a cold night can cool the stream enough to negate the effects of the daytime temperature. For example, a day with a high of 32 following a nightly low of 30 will probably be more productive than a day with a high of 40 and a low of 20.

In the summer the sun can raise temperatures to dangerous levels, so poorly shaded streams should be avoided on sunny days, or at least at midday. High air temperatures can also cause temperature problems, but this is likely unless the day is unseasonably warm.

Feeding Activity

Different weather conditions can lead to wildly different feeding patterns in trout. For this discussion, I’ll consider three general conditions: Sunny, Overcast, and Rainy.

Sunny Days

The brighter the day, the more visible everything is. This means that both trout and their food sources are at higher risk of predation and are therefore less active. It also lets trout see your flies, line, and shadows more easily, increasing the risk of spooking a fish. That’s not to say it’s impossible to catch fish on a sunny day. Focus on riffled areas, where trout are less visible from above, and you’ll likely find fish.

Overcast Days

Overcast days are ideal for fishing. Trout are more active, and many insects are more likely to hatch. You also won’t cast a shadow, so the risk of spooking fish is much lower. The only exception is in winter, when water temperatures are often too low on cloudy days.

Rainy Days

If you can stand being outside, rainy days are even better than overcast days. All of the advantages of overcast days still apply, and the rain adds further benefits. Rain breaks up the surface of the water, making it more difficult for the fish to see you. This is great on flat spring creeks where fish usually won’t let you get close enough to cast without spooking. Rain also washes terrestrials into the stream, which results in active fish. The only potential downside of rain is that it can raise water levels to unfishable levels.

The last element of weather to which I pay attention is wind. It can be a bit of a wildcard. Although wind can break up the surface of the water and blow terrestrials into the water, it also makes casting difficult. Personally, I feel the negatives outweigh the positives on days with wind over 10 mph, but his is my last consideration.

Hopefully this helps in planning future trips!

An Underrated "Hatch"

Photo Credit : D. Garding

I first discovered the importance of inchworms in trout fishing last May. I was fishing a sea-run brook trout stream where the trout take streamers almost exclusively. On this particular day, however, I didn’t get a single strike on my go-to brookie streamer, the Mickey Finn. I decided to try a black wooly bugger instead.

I cast the wooly bugger into a pool and it was met with a sudden rise.

Too sudden.

The Wooly Bugger’s magic lies in the lifelike motion of its marabou tail. But this fish struck long before it would have had time to see any motion in the tail. I got the fish in, still confused as to why the trout struck so quickly, but happy to catch a fish. After all, it doesn’t matter to me why a fish strikes.

When I looked into its mouth to remove the fly, it immediately became clear why the trout struck on the surface. Three bright green inchworms were lodged in its throat.

Photo Credit: David Illig

For the next two weeks I paid close attention to inch worms every time I fished. I noticed a few characteristics that make inchworms good flies to try:

Where there’s one, there are many

Inchworms are the caterpillars of Geometer Moths, a widely distributed family containing over 35,000 species. These caterpillars congregate on their preferred tree species, so you’ll typically find many individuals in a small area.

They’re clumsy

Inchworms often fall out of trees. When they fall, they suspend themselves on a thin piece of silk, but they don’t seem to have the strength to pull themselves back up. This means you will often see an inch worm drop slowly towards the surface of the water from an overhanging branch. The fish can see this too, so they have plenty of time to set up below the falling worm and wait for it to hit the water. I’ve even seen a bluegill clear the water to grab an inchworm that hadn’t yet hit the surface.

They float

Inch worms float high on the surface, and I’ve never seen one drift long enough to sink without being eaten. Everyone likes fishing dries, and with inch worms active in the middle of the day, there is a rare opportunity for midday dry fly fishing.

For some reason, inchworm flies are not common. Maybe its because they’re considered “Junk Flies” like eggs and San Juan worms, or maybe people just don’t realize trout eat them. Whatever the reason, a lot of people are missing out. My black wooly bugger worked, but it isn’t the best imitation and likely wouldn’t work on selective fish. After that outing I bought some greenie weenies, and they worked, but they don’t float and most fish were taking worms from the surface. If any fly-tiers want to come up with their own pattern, I think a floating foam fly would work perfectly.

Last year the inchworms were peaking in MA in mid-may, but this year’s long winter might push that back a few weeks. Be on the lookout for these little green guys this spring and you might find a great day of fishing!

Nice Weather and a Brook Trout

I think I was the only one up at 6:30 on a Saturday...

I fished yesterday morning, hoping to take advantage of a nice day before the Lower Kinni got crowded.

Leaving St. Paul at sunrise

I arrived at the parking lot at 7:30, happy to see I was only the third car there. Unfortunately it was still cold in the canyon, so I spent an hour cleaning ice off my guides before I decided to move upstream in search of warmer waters.

Kinni Canyon

More Canyon

I drove to a small tributary to the Upper Kinni and almost immediately had a hit in the first pool I fished. That fish got off, but a few casts later I pulled in this nice brookie. I had several more hits in the same pool, but I failed to hook up with any of them. 

Nicely colored wild brookie

With the sun getting higher in the sky, I decided to fish a shaded stretch of the Upper Kinni where my shadow would be less likely to spook fish. Despite several more strikes, I was unable to land another fish. It was a day of long distance releases, but it's hard to complain. I'm just happy to be fishing without a coat. 

Upper Kinni

Using Science to Inform Fly Fishing

For much of the winter, I satisfied my fishing urges by researching the science of trout behavior and habitat. This research has proven useful both in finding likely streams and in catching fish. I think this info will also be helpful to others, so I'm planning to do a series of short articles on some of the ways science can influence fly fishing.

Possible topics:

Biology

• Trout feeding behavior
• Preferred trout holding water
• Seasonal movement of trout
• How water temperature affects trout behavior
• Trout diet
• Aquatic invertebrate behavior

Chemistry

• Effect of pH on Trout and aquatic invertebrates
• How geology affects water chemistry
• How acid rain affects trout streams

 Geology

• Differences in bedrock geology and how it affects trout streams
• How to find streams with groundwater influence
• How stream gradient affects trout
• Erosion

Physics/Meterology

• How air temperature affects water temperature
• How sun affects trout behavior
• How air pressure affects fishing
• Making the most of weather forecasts
• How light behaves underwater and effects on trout vision 

This list will keep me occupied for a while, but it isn't exhaustive - I'll see what else I think of as I go along.

Part I:

pH - What is it and how does it affect trout?

pH is a measure of the acidity of a sample of water. All water samples contain both hydrogen ions (H⁺) and hydroxide ions (OH^-). When the concentrations of these two ions are equal, the water is said to be neutral and has a pH of 7. When the concentration of hydroxide ions is higher than the concentration of hydrogen ions, the pH is greater than 7 and the water is said to be basic. When the concentration of hydrogen ions is higher than the concentration of hydroxide ions, the pH is less than 7 and the water is said to be acidic.

pH affects trout in several ways:

Adult Habitat:

Adult trout can handle a fairly wide range of pH levels. Brook trout are the most tolerant of acidity, with a minimum pH of about 4.5 and a maximum of 9.5. Most natural streams have a pH between 5.5 and 8.5, so Brook trout can tolerate most streams. Brown trout are somewhat less tolerant, with a lower pH limit of 5 and an upper limit of 9.5. Rainbow trout are the least tolerant, preferring water ranging in pH from 5.5 to 9.5. Streams within a given species' pH range will provide suitable adult habitat, while those outside it will not.

Food Availability:

Aquatic invertebrates, the main food source for trout, are sensitive to pH. Freshwater crustaceans in particular can't tolerate acidic water, as the acid increases the solubility of calcium carbonate in their shells.Scuds and crayfish can be very important year-round components of trout diet, so streams containing crustaceans are usually more productive in terms of both numbers and sizes of trout.

Spawning Success:

While all adult trout species have somewhat wide pH ranges, young trout are more more sensitive. With a minimum pH of 5.0 for spawning, brook trout are again the most tolerant. Brown trout prefer a pH over 5.5, while rainbow trout will not spawn in waters above pH 6.5. In New England, where many of our streams are both naturally acidic and impacted by acid rain, brook trout are by far the most common wild trout species. Wild browns exist in some streams with higher natural pH, but are somewhat rare. Wild rainbows are especially rare, especially in southern New England, both because they have the highest minimum pH for successful spawning, and because they spawn in the spring, when pH is naturally lowest.

Why is the pH low in spring? Even in the most pristine parts of the world, rain and snow are somewhat acidic, with a typical pH of about 5.6. Add pollution into the mix and you have a serious problem. When the snowpack melts in the spring, all of that acidic precipitation is released into streams at once. Because the snowmelt typically coincides with rainbow trout spawning, eggs and/or young of the year are often killed by this spike in acidity. The only New England streams where wild rainbows are able to survive are those with a high buffering capacity, or ability to resist changes in pH.

Buffering capacity is primarily a function of geology. Carbonate ions are responsible for most of the buffering that occurs in trout streams. Limestone is probably the most common carbonate-containing rock, but there are many other types of carbonate rock, including marble and dolomite. The USGS provides bedrock geology maps for every state, so I often look up the bedrock underlying my stream of interest. If I don't know what it is, I do a Google search for "(insert rock here) buffering capacity" or "(insert rock here) acid rain", which usually turns up some information on the buffering capacity of that rock. A simpler method is just to look for rocks with "calc" or "carbonate' in the name - these rocks often have high buffering capacity.

Though it may seem complicated at first, a good understanding of pH can be beneficial to many aspects of fly fishing, including locating productive streams, determining the species likely to be present in a given stream, and selecting flies.

Perfection Loops

I recently learned to tie the perfection loop knot. It's usually used to create a loop at the butt end of the leader, and it works great for that purpose, but I've been tying them into the tippet end of my leader. This way I can attach pieces of tippet quickly and easily with an improved clinch knot. This is the great in cold weather when its hard to tie more complicated knots.

Here's a good animated tutorial to tie the perfection loop.

When I tie a loop the end of my leader I try to make the it as small as possible. I tie the knot loosely at first, then feed extra line from the loop into the knot and pull out slack with the tag end.

See Diagram:

I usually put a thumb tack through the loop into my desk as I tighten the loop. It helps protect the slipping through the knot as I tighten and it's about the same diameter as the loop I want. It took me a few tries to get it down, but overall I find this knot fairly easy to tie. I've appreciated the easy tippet changes and longer leader life this loop provides. My only worry is that it may not be as strong as conventional knots,  but so far I haven't had a problem.

This probably isn't the most conventional set up, but I'm fine with unconventional if it functions the way I want. 

Driftless Afternoon

Sunday's forecast called for temperatures in the low 50s and overcast skies - not most people's definition of good weather, but great for fishing. While sunny days are nice, they increase the visibility of trout to predators. The trout know this, and as a result they tend to be pretty spooky in the sun.

I hit a small stream I've fished a lot lately, hoping to find the fish more willing than usual. Willing they were, and I started off with this small brown on a BH prince nymph.

Small is ok! I like catching a variety of sizes

The BWO hatch is on in the Driftless

A few casts later my indicator dove, and I felt significant weight on the other end. This 12" brown put up a serious fight in the small stream, making every effort to get me tangled in the stream-side brush. I got him in though. I've seen fish this size that last few times I visited the stream, but never hooked anything over 8", so I was pumped!

Biggest trout I've caught in this stream

Released

As I was walking out I passed this small backwater section of stream. I always assumed this area was shallow and devoid of live, so I was surprised to see rising fish. As I walked towards the end I realized that it was much deeper than I had thought, reaching at least 4 feet deep in spots, and that it must be spring fed. There's almost no current, so I guess I found a miniature spring-fed trout pond!

Backwater

I hooked up with a small fish on my first cast, but was disappointed when I realized it was not a

Trout, but a small chub. A few casts later I had another hookup, and reeled in another chub. I worried that maybe there weren't any Trout here after all. Just as I was about to leave I saw another splashy rise, and I realized there was no way a chub could make that kind of splash. A few casts later I got what I was looking for - a nice "pond"-dwelling brown.

Resident of the "Pond"

Bloodroot - one of the first wildflowers of the year

More Dry Fly Fishing

I got out Tuesday morning for a couple of hours.

Foggy Morning

It was foggy when I started on the Lower Kinni and had several strikes and one hookup on a beadhead copper john. The fog soon burned off and the fishing slowed down, so I headed to a small stream.

Still haven't gotten used to catching trout in the middle of a corn field...

There was a good midge hatch coming off, but I managed to spook all of the rising fish I saw. Not wanting to leave empty handed, I carried on. I reached a nice plunge pool with some fast moving water in the tail-out. This is the kind of water I love. The rippled surface prevents the fish from seeing you and the fast currents mean they have little time to scrutinize your fly.

I made a cast into the middle of the pool and my fly was greeted nearly immediately by a large splash. I set the hook and the fight was on. The brown put up a good fight, but I wasn't going to let this one go.

This brown had some meat on his bones 

He was the only fish of the day, but it felt good to end the outing on a fish.