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Friday, January 30, 2015

Even more smallmouth locations

Here we have the site of an old dam that has been washed out. There are literally hundreds of these on Midwestern rivers and streams. Many powered old mills or factories around the turn of the century. Spots marked A are smaller pieces of rubble in the fast water that are only big enough to hold a single fish. In the swift water pouring thru the breach in the dam these spots can be hard to find. But potentially they hold some great fish and are worth search for. A swimbait or grub on a heavy jighead to get it down works great here. Often cast cross current and slightly upstream and letting the lure sweep down on a tight line is best. Spots marked B are bigger pieces of rubble fronm the old dam and can hold multiple fish. If they are undercut or naturally contain holes or pockets they can hold some big shovelhead as well. One thing to remember is that sometimes this is another spot where casting close to or even hitting the object with your lure can pay big dividends. Sauger sometimes also hold on this kind of place just not as closely as the smallmouth. Most old dams are undercut as at spot C if there is current flowing against the undercut it can hold nice smallies. These undercuts are also great places for a big shovelhead as well. Spot D is the bar formed by the downstream lip of the old dam when it was whole. This fishes like any other riffle but has the added benefit of being close to the deep water around the old dam. Expect some nice fish to be on this riffle at low light.

Some basic smallmouth locations

Here at point A we have a typical riffle in a stream. Right in the riffle, the water is too fast for bass to stay in for extended periods of time unless there is something to break the current. Instead bass will move in and out of the riffle feeding on the large amount of food there. Think of the riffle as the main dining area in a river. Just upstream of the riffle we have the tail of the pool immediately upstream.
As the river shallows and the water quickens to go over the riffle the force of the water keeps any silt from settling on the bottom. And the two things smallmouth like best are a bit of current and a hard bottom. If this tail is a smooth glide into the riffle as many are it's a great place to throw a topwater. Spinners and crankbaits also are effective here. I sometimes think that tails of pools are what roostertails were designed for. C and D are side eddies where water swirls back and travels upstream losing much of it's force. While these can contain feeding fish at times the seam where the eddy and the fast water coming downstream is the money spot. If as in F this seam extends downstream for quite a ways and there is a distinct line between the fast and slow water you can expect this to be a spot a better fish might feed at. Spot E is a fish staging behind a rock on the bottom of the run between the riffle and the pool. Most of the time these underwater rocks will betray their presence by a boil or slick on the surface, A sudden dip or depression in the bottom will also cause a slick on the surface and just like the rock create a spot for a fish to lay out of the current and ambush prey. Spots F and E scream grub or swimbait to me. One thing to remember about rocks is that smallmouth will sometimes have a tendency to hold extremely tight to them. Try bouncing a crankbait or a jig right off the rock on the retrieve, this can sometimes trigger a strike.

Smallmouth location

The next drawing depicts one of my favorite kind of river sections. It has an island followed by a bend with a point bar. Point A the head of the island often fishes much like a regular riffle with the added bonus of having deep water very close by in the main river channel. Spot B the bottom of the island also has good feeding locations but not quite as much on average as the upstream end of the channel. This is often an ideal place for bass to spawn as there is enough current to keep a firm bottom but it's still sheltered from the main river current. The shallow channel behind the island will hold rock bass or longeared sunfish if there is enough cover and a few deep spots. Spot C is a small eddy formed tight against the island by a big rock, maybe a log or just the shape of the island these are usually just one fish spots but it can be a very good fish. Spots marked with a D are underwater rocks that create holding stations for fish in the deep swift channel running past the island. Just like rocks underwater below a riffle they usually create a boil or a slick on the surface to let you know where they are. Spots E and F are prime shovelhead locations. If the deep steep bank in a bend like F is undercut and has a hole you can be sure a shovelhead uses it. Spot G is the point bar across from the deep bend. As water speeds up go around the outside of the bend it travels faster than the water traveling around the inside of the bend, So a bar is built up on the inside of the bend while a hole is dug out on the outside. Remember that the material on the deepest end of the bar is smaller on average than the material at the base. All kinds of things like different species of darters prefer rocks of a certain size. So depending on what the bass are feeding on that day they may find one band or depth of the bar much more to their liking that day. It pays to try fishing each depth rather than just walking to the end of the bar and casting towards the hole.

The incredible edible crayfish...

 So the fishing has been slow. I've been out and caught the occasional saugfish, been skunked a few times, heck today I caught a four or five pound buffalo. In other words it's been nothing to write home about, much less make a report about. Dan and I did catch a bunch of big gar one day in a creek mouth in the Ohio river. But I kind of look at gar like bachelor parties, sure their fun at the time but you don't go around telling everybody what happened either. So besides this little bit of fishing and some wishing for spring I've been trying to learn a bit more about the river. Lately I've been studying crayfish. What a weird little creature they are if you take the time to really look and learn about them. Here's a bit of what I've learned...
Crayfish are part of the largest grouping of animals on earth called arthropods. Arthropods have hard exoskeletons and include insects, arachnids and crustaceans. Crayfish are crustaceans and differ from insects in that they breathe with gills and have two pairs of antennae. Crustaceans are also the yummy group and include stuff we love to eat like lobsters, crabs and shrimp. And well, crayfish. If you haven't ever eaten crayfish but like the other stuff on that list your missing out, they are delicious. And as every fisherman worth the name knows, the fish think they are delicious also. So here's more than you ever wanted to know about crayfish:
Back to those antennae, crawfish have a long pair and a short pair. The long whiplike pair help the crawdad keep track of what's going on ahead and behind it while the shorter stubby ones are for close in work. From everything I've read they are like a poor man's version of catfish whiskers in that they are sensitive to both touch and smell. Crayfish also have compound eyes on the ends of little stalks.
I'm not sure exactly how clear a crayfish sees it's world but compound eyes detect movement extremely well. The eyes mounted on stalks are called pedicles.  If you watch a live crayfish, you can see the eyes move independently of each other.  Instead of ears crawdads have thousands of tiny sensory bristles that can sense vibrations. The "brain" of a crayfish is just a mass of nerve ganglion just in front of and above the esophagus. I'm pretty sure most crayfish behavior is instinctive and they aren't exactly rocket scientists.
A crayfish has four pair of walking legs. The small appendages along the underside of the abdomen are the swimmerets.  These help the gills circulate water through the body, so the crayfish can breath. And if you ever want to, you look at the first pair to determine the sex of a crayfish. (don't ask me, you might want to...)  In boy crawdads, this first pair is used to deposit sperm into the oviducts of the female. They are larger and harder than the others. In girl crawfish, all the swimmerets are soft and used to carry the fertilized eggs and newly hatched young. Crayfish have 3 sets of tiny appendages around their mouth called maxillipeds. These appendages help the crayfish manipulate food.
All in all crayfish have 38 pair of appendages! Of course the ones we are all familiar with is that first pair with the big pincers on them. These are used to gather food and defend the crayfish from predators like fish. And don't think they don't use them to defend themselves, just let a big one you catch out of the river sometime latch on to you and you will change your tune. In fact studies have shown that smallmouth bass over and over again select crayfish with smaller claws if given  choice. The old river rat trick of pinching the claws off crawdads you use for bait really does up you catch rate.
Along with claw size, studies show smallmouth bass select crayfish by body size also. The interesting part is that the biggest smallmouth bass, the trophy fish are the most selective by size. They consistently choose a crayfish about an inch and a quarter long if given a choice. I wonder if, given a smallmouth's long lifespan, that a ten or twelve year old bass has just learned by experience that those big craws can be bad news. Those big lobsters you sometimes see are shovelhead bait not bass bait unless the fish is really hungry. And even then the bass is going to suck that big craw in and blow it out several times trying to kill it, making it harder to hook on a bigger crayfish imitation too. If it's claws can't defend it, the crawfish's other option is to flee. This it will do by a sudden flip of it's tail which will cause it to jet backwards a foot or so amazingly fast.
In the Midwest most crayfish mate in the fall. (don't ask me how, don't know, don't wanna know)
Then in spring the female will lay eggs which she glues to the swimmerets on her abdomen. These then hatch in 5 to 8 weeks into tiny crayfish which hang on another week or two before dropping off to fend for themselves. And along the way feed nearly everything in the river it seems. Everything from minnows like larger darters and chubs to dragonfly and hellgrammite larvae. There are some you tube videos of dragonfly nymphs eating little crayfish out there that are right out of a horror movie.
But crayfish are omnivores and get their revenge if they are lucky enough to grow up. Along with a bunch of vegetable matter they will chomp on pretty much anything that's small enough to kill with those pincers including things like small minnows. And as anyone who has went after crayfish with a minnow trap will tell you, dog food  is a classic crawdad bait. Like I said an omnivore.
Crayfish undergo periodic moults, shedding the hard  exoskeleton in order to grow larger, and then forming a new shell. During this time they are in fishing lingo, "soft craws" and extremely vulnerable to predators. And fish know this and moulting crayfish are just about the best live bait you can use. But don't discount using "hard craws" that are not moulting. Just remember what I said earlier about bigger bass preferring a small crayfish in the inch and a quarter range. Another interesting tidbit is that a crayfish can regenerate a claw if it loses it battling a fish or I dunno, a bigger crayfish. Over the course of two or three moults the claw will grow back. Which reminds me that when catching crabs in South Carolina it was illegal to keep the huge but somewhat rare stone crab. But you could keep one of the huge claws of this overgrown relative of the crawdad since it too would regenerate. (And one stone crab claw had more meat that a couple whole blue crabs.)
Speaking of eating crayfish, they aren't just for smallmouth. Besides smallmouth, channel and flathead catfish, walleye, saugeye, carp, trout, largemouth bass, freshwater drum and I'm sure a host of other fish eat crayfish. And of course people eat crayfish. My personal favorite way is grilled smothered in garlic butter and Cajun seasoning. But of course crayfish are famous as smallmouth food. And with good reason, a 12 inch smallmouth bass in late summer fills up to 70% of its diet with crayfish. Larger bass eat a lot of baitfish but they still eat a bunch of crayfish too. BTW don't ever, even on a drunken dare for a hundred bucks eat a live crawfish (or a raw dead one). A big percentage of crayfish are infected with a parasitic flatworm called a lungworm. After you scarf down the crawfish, the parasite comes out and burrows through the walls of the intestine, hoping to make it to the lungs where they can complete their life cycle and mature. Once in the lungs they form nodules that mature and grow. But sometimes they don't make it and get lost on the way to the lungs and they can end up in other organs, even in your brain. Yeah, YUK.
There are approximately 600 species in the world. Of those something like 350 live in North America. Which I'm guessing is more than the number of people who could tell them all apart.
Btw an Astacologist is someone who studies crayfish. And if you think the crawdads in grandpas pond are huge, the world's largest crayfish lives in Tasmania and can sometimes grow up to ten pounds! These giant crayfish can live up to 40 years too! Google Astacopsis gouldii, which is their latin name if you want to see some amazing photos. There are also colorless blind crayfish that have evolved to live in caves. According to ODNR there are twenty species of crayfish in Ohio.
If you keep crayfish for an extended period of time before using them as bait they will stay alive for a long time if you remember a couple things. First and foremost don't keep them in a bucket half filled with water unless it is aerated. But they don't need to be in aerated water if you keep them in something like a cooler with just a tiny bit of water in the bottom and something like grass that they can crawl up on. You see if they can keep their gills moist they can breath air also. And try to keep the same size crayfish together, the big guys will definitely kill the little guys.

Sunday, January 25, 2015

Low head Dam Fishing

Smallmouth country is low head dam country.  Tens of thousands used to exist back in the day to power factories and mills. A lot still exist today.  Pennsylvania, Illinois and Ohio alone have somewhere in the neighborhood of 800. I couldn't find numbers on neighboring states like Kentucky or Indiana but off the top of my head I can think of more in those two states than I can in my home state of Ohio. West Virginia, Tennessee, Virginia, if it's smallie country, It's lo head country.  From small ones it's safe to wade around up to large ones on medium and large rivers like the Kentucky or Scioto that are drowning machines.  Safety has to be a high priority any time one is fishing or boating around a low head dam of any size. Most low head dams form a powerful circulating current below them called a hydraulic that will drown the strongest swimmer even if he is wearing a life vest. In the last twenty years between 3 and 4 hundred people have drowned below low head dams in the US so this isn't a "it can't happen to me" type of scenario. If you do not treat low head dams with respect it could easily happen to you.
All that being said, low head dams are also often among the best places to fish on any stream that has them. You can find large numbers of schooling baitfish like shad, shiners and even skipjacks if you are close to a big river like the Ohio River. In other words lots of food for gamefish. Plus current, gravel, rock, concrete. oxygenated water full of eddies and seams. Dams are just all around great places to fish. So let's talk a bit about how to fish them. Most low head dams are not just a wall in the river. Instead the water falls in two steps to dissipate the water's energy and keep it from digging the river bottom out too much. But all that falling water still has lots of power and it does dig out a hole below the dam called a scour hole. It's been m experience that every low head dam also has some sort of undercutting going on as it ages. This can create a hidden home for big fish even a heavily fished dams.

In this drawing you can easily see why such undercutting would be attractive to fish. Overhead cover, oxygen,   a strong recirculating current bring food while the fish itself rests in relatively calmer water,  what's not to love if your a fish? And 90% of the fishermen who visit the dam don't target the fish tucked up under the dam itself. It's a recipe for a trophy. Below the smallest shallowest dams where it is safe to wade close to the dam, casting a diving crankbait  or a sinking or suspending minnow plug along the dam lengthwise can produce great results. Just remember that even tiny low heads can be deadly in times of heavier flows. Below larger dams where it is too deep or too dangerous to wade right next to the dam the current is too strong for most crankbaits to run well. Here a heavily weighted jig head is often your best bet. Other good lures to try are blade baits like silver buddies and tail spinners like the little George. Compact and heavy are the rules here, you want something to cut the current and get down to calmer water under the lip.

Let's expand our look at our low head just a bit. Many low heads have a secondary hydraulic right at the base of the main fall of water. (A) Here you often see carp in the summer trying to make their way up and over the dam. It's been m experience that at most dams this area does not hold many smallmouth bass, at least not sizeable ones. Sometimes though, there are very nice channel cat foraging up here in very swift shallow water that no one seem to target. Casting a bait up onto the dam itself and letting it fall into this area can produce some unlikely but exciting catfish catches.
Then we have our undercut we just talked about (C). Just blow this is the main hydraulic or circulating current. I've seen shovelheads, channels, smallmouth and hybrid stripers high in water column here if large schools of baitfish are present. Below this boil a calmer current flows along the holes bottom. On a big dam you might find blue cats here as well as saugeye holding up during the day. Too often though this area is devoid of cover and not the best place to fish. Oddly enough this is the most fished part of the dam. Lastly we have the lip where the scour hole ends. Often there are gravel and rock bars thrown up here even to the point of forming small islands in the river. These create lots of different seams of conflicting currents that can be fish magnets. These bars often have lots of rock that hold crayfish and darters for gamefish to feed on.

At many older low heads large boulders and concrete rubble have been dumped to control the undercutting of the dam (A). This provides great cover for crayfish, insect life, sculpins, darters and well, lots of smallie food. This is done most often done at older dams that have already been undercut so there are usually nooks and crannies for smallmouth to get into also. If the holes are big enough, and they usually are somewhere along the dam, here is where a big shovelhead will hide during the day also. Over time, during flood events, some of this rock and rubble is naturally washed into the scour hole (B). Now instead of a featureless bowl there is plenty of fish holding structure. And of course some of this also ends up on the bar at the lip of the hole (C). All in all these older dams are some of the most interesting ones to fish and my favorite kind of dam.
It's very important to realize that a fish doesn't interact with it's environment in the 2 D sort of way we do walking on the ground. Instead it see's it's world in a 3 D way much as a bird flying in the air does. Even more so really as the water currents are much stronger than air currents. To a smallmouth a strong seam is an object as real as a building. Low head dams produce all sorts of currents too many to discuss really. Just remember that smallmouth love edges. Anywhere you see an edge, a seam where faster and slower water meet is worth trying below a low head. Often on at least one side or the other below a dam eddies or other respites from the current exist (C). These can be large swirling eddies as big as a house where the dam meets the bank or smaller individual ones created by concrete rubble dumped to prevent bank erosion. Again either way they produce edges where faster and slower water meet. Our undercuts (A) that we already discussed can also channel the water flowing over the dam and create seams all along the dam face. Keep an eye out for pockets of foam just sitting there indicating a calm spot in the turbulent boil below the dam. Likewise the bars formed at the scour holes end (B) are not uniform and create chutes of faster and slower water as well as water channeled sideways across the river. These chutes can create channels down below the dam for quite a ways (D) that if deep enough can hold lots of fish. If there is a theme throughout this whole discussion, it is to spot the edges. When you first look below a dam is just seems a huge mass of disorder and chaos. Slow down a minute and look at pieces of the water. Find calm spots, edges, seams. The longer and closer you look the more it will all "slow down" and begin to make a bit more sense to you. Though complicated and nothing like the "reading the water" we are used to, they are more than worth the time to learn to fish. Just remember each dam is a bit different from every other dam and looking, learning and experimenting are the name of the game.

Saturday, January 24, 2015

Typical river configuration

Here is my exaggerated drawing of a typical piece of a small to medium sized river. A riffle of large course material followed by a run of slightly smaller material diminishing in size till it merges with the silt and sediment of the pool before the whole thing repeats itself again. The idea that the material that makes up the rivers bottom follows this pattern of course rocks tapering down to silt is an important one for fishermen to remember. The bigger rocky material of the riffle harbors all kinds of prey for a predator like a smallmouth bass. Crayfish, hellgrammites, darters and sculpins abound in riffles. The fast water flowing over the riffle also adds lots of oxygen to the water. Many different species of insects also find homes in the rocky water of riffles. A run is the transition area between the riffle and the pool. Although not usually as rocky as the riffle, runs still have a rock or gravel bottom. Along with many of the same species as the riffle, other species such as different kinds of minnows and shiners join the mix here. A run with boulders or a ledge or anything else that provides a place for smallmouth to find a spot out of current but still have food carried to them by the current is almost always a good spot to fish. The deeper pools generally have softer silt covered bottoms and are populated by shiners and minnows that feed higher in the water column. Cover in pools might harbor largemouth bass or some crappie as well as the most beautiful little fish on earth, the longeared sunfish. Again picturing in your mind that the bottom changes over a length of river can be key in figuring out how and where to fish it.

After the flood

Now our point might harbor the ultimate secret spot.  Along comes a huge event, that 100 year flood. The whole river is in a raging flood many times higher than normal floods. And the raging river knocks the end off our point. The very biggest material that isn't completely swept away is now directly downstream from the new tip of the point. So you now have a deep instead of gradual slope off the end of the point. This creates a really strong seam downstream sometimes for thirty or forty yards. And for extra good measure all kinds of really big rocks under the seam for bass to stage under and ambush stuff. (C thru D) Hole run seam point and cover rocks all together. The key is to recognize a point that doesn't seem to taper off correctly and to realize you need to fish straight downstream of the tip of the point.  Just upstream of the bar (A)  is now deeper with flow a great spot to find a big saugeye or channel cat. Now strong current flows off the end of our shortened point and a seam might set up all the way from A to D. If this seam is anywhere near a deeper wintering hole for smallmouth it might just be the best spot in the entire rivers length to catch a trophy every fall. The flood event which  knocked the end off the point has probably deepened the hole (D) even more than usual if any wood cover is present in the hole you can be sure a trophy flathead has set up housekeeping there for the summer also. Points and bars thrown out into the river by tributaries are also candidates to have this same situation occur. No matter how they are caused any seem that has a line of big boulders strung along it's length is the destination spot on any river that has one.

Lateral Sort and Point Bars

This illustration shows a point bar on the inside of a bend in a typical stream. This constriction in the rivers channel makes the current speed up as it goes around the point. As you know a spot close to the center of a wheel is turning slower than a spot on the rim of a wheel. The water curving around the point also has to do the same so the faster swifter water on the outside of the bend digs out the bottom and far bank creating a hole off the end of the point. As the hole is eroded over time there is more pressure by the faster water on the outside side of any material dislodged. Also often a secondary current right on the bottom is often set up. These result in dislodged objects being moved slightly towards the point every time they are moved by high waters. In multiple high water events the bigger material is moved closer to the point while smaller material is swept away. Over the course of many many years this can sometimes result in a lateral sort of the rocky material off the point. With the biggest stuff that has stayed on the point after repeated events being right at the tip of the point and steadily smaller and smaller stuff laid down in strips as you go farther from the point. What's this got to do with fishing? Well crayfish and darters love rocks. Stuff the size of a grapefruit especially. So somewhere along the width of our point and pool of sorted rocks is a strip of bottom that is ideally suited for them creating a mini city of smallie food. (B in our diagram) While the outside side of the hole might be swept bare of bigger rocks and is just a layer of fine gravel deposited between big events. In other words NOT crayfish and darter cover. (C)  Now sometimes shiners will use this fast water pouring over bare gravel too so you do need to throw a cast or two there too.
But what happens is a guy comes along fishing beaches his yak or canoe and walks out to the end of the point. He then makes a nice average cast to the center of the hole and fishes his lure downstream thru the hole. He reels in repeats and does this a dozen times. If he doesn't catch a fish he moves on. Well he cast over top of the sweet spot and his lure was barely in in it. Sometimes we are reeling in and catch a fish seemingly right at our feet. When this happens make sure its not a lateral sort situation. Cover the holes off the ends of points laterally with each cast following a different path that the previous. Right along the steepest banks in bend pools if there is any cover is the ideal habitat for a shovelhead to make his home. (D) Below the bar (A), if the bottom is hard enough can be spawning habitat as well as a place for fish to move up shallow at night and feed.

Sunday, January 18, 2015

Some shiny lil fishes

For a complete list of all fish species in the Great and Little Miami as well as the Whitewater check out this link

Here are some highlites of some of my favorites:

Emerald Shiner

The emerald shiner, like most shiners, is laterally compressed, which means they are taller than they are wide. Their sides are a shiny silver color and can also have an emerald green hue. I like to use crystal flash when tying jigs or flies to imitate shiners because of their metallic shiney sheen. Emerald shiners are broadcast spawners which is a fancy way to say they are lousy parents and just spray out eggs willy nilly and give no care to their young. Pool dwellers, they are usually found in open water and stay near the surface.  They feed on zooplankton, insect larvae, and small flying insects such as midges.

Spotfin Shiner

Spotfin shiners are one of the two most common minnow species (second only to the bluntnose minnow) found in Ohio. They are solid silver, sometimes with a bluish cast. Spotfins also have, you guessed it, one or two elongated spots on their dorsal fins. Able to thrive in reservoirs, spotfins often inhabit the pools of our streams. They tend to eat a variety of aquatic invertebrates. These guys  spawn in crevices between rocks or in bark on limbs of submerged fallen trees.


Chubs are one of the most common fish in most streams. They are even abundant in  very small trickles where they are often the top predator. They feed on a wide variety of aquatic and terrestrial insect larvae and other invertebrates. Large chubs will even eat small crayfish and fish. Chubs can even be caught on a little piece of worm under a tiny float and many caught this way end up as shovelhead bait. Catching a chub or two is also a byproduct of any trip spent fishing small flies on the fly rod.

Central Stoneroller

One of the most common fish in the smallmouth streams of the Midwest is the central stoneroller. I like to think of central stonerollers as solar batteries for smallmouth. You see central stonerollers are the champions of algae eaters and  may consume up to 27 percent of their body weight in algae per day. The algae thru the miracle of photosynthesis converts sunlight into energy. The algae in turn is eaten by stonerollers and then eaten by smallmouth bass. Nice direct line, simple is always better right? Well, except that according to Wikipedia there are over 72,500 algal species worldwide in most recent estimates and maybe more than a 1000 in a single river like the Little Miami. But that's a topic for another day, back to central stonerollers. Central stonerollers have a lower jaw with a flat, shelflike extension used to scrape algae from rocks. Omnivores, central stonerollers eat detritus, animal matter, and terrestrial vegetation besides the algae that makes u almost half of their diet. Adults range in length from 3 to 5 inches, but they can reach 7 inches. Males are generally larger than females.
 It takes one to four years for central stonerollers to reach maturity. Breeding males begin building nests in late winter and continue throughout midsummer, creating large, bowl-shaped depressions   just upstream or downstream of riffles by rolling stones along the bottom with their noses . Which is where they get the name stonerollers. The males aggressively defend their nests against rival males. Spawning occurs in early spring and summer. Females remain in deeper water outside the nesting site, entering only briefly to produce up to 4800 eggs in a nest. The male fertilizes the eggs, causing them to stick to the gravel of the nest, preventing them from being carried away by the currents.
When it comes to their appearance, it seems every source I find uses the word stout to describe them so I'll go with that that. Stout brownish minnows with breeding males that have some orange and black on their fins, large pointed tubercles (horn like bumps) on their head, and reddish orange eyes.
That's a pretty wild description and also accurate.

Thursday, January 15, 2015

A little bit about Darters

With winter upon us, I'm trying to bone up a bit on the complicated food chain in our rivers. Today a bit on darters...
Darters are among the most ecologically important  fishes found in found in the  streams of the midwest. In many sections of stream up to a third of all fish species will be some kind of darter. But most fishermen that wade and fish these same streams know little or nothing about them.
Darters are also an important piece of that big puzzle we are always trying to put together when we are out on the water. So here is a mini primer on these cool little fish.
Each species of darter has evolved to occupy a specific slot or niche in the food chain. That is why there are often several species in the same section of riffle. Some may occupy bigger rocks and rubble than others. Some species may live in more current or shallower or deeper water than other species. In my favorite river, the Little Miami, there are a dozen species alone.  Darters prey on insects and crustaceans, and in turn are preyed on by species such as smallmouth bass and saugeye. Darters are an indispensable  link in the food chain. The presence of darters in a stream reflects good water quality and diversity of healthy habitats.
A darter is built to maneuver in, around and under rocks and gives it an advantage as a bottom forager. Fast swift riffles provide protection for darters because few predators can live there and must move in and out even if they do forage there. In nature, it is usually true that "form follows function."  Many darters do not even possess a swim bladder. This lack of buoyancy allows them to stay near the bottom in swift currents. Many bottom-dwelling darters possess flattened, downward-sloping heads. This feature lets them take advantage of water flowing to help plane or push down on the fish's head, thereby helping the fish to remain near the bottom. Some darter species that live at mid-water depths do possess a swim bladder to help them remain suspended in the water column.
Darters are small. However, there is considerable variation in length among the species found in  our rivers, anywhere from an inch or so up to six inches long.
What darters eat varies with the lifestage of the fish. Juvenile darters chomp on small crustaceans such as water fleas, plankton and zooplankton . Adults prefer midge larvae, blackfly larvae, mayflies  and caddisflies. Larger darters species  may also eat amphipods freshwater shrimp, isopods sowbugs and crayfish. Darters do not compete with most minnow species because the minnows often occupy the upper levels of the water column. Food availability and water velocity help to determine the activity levels of darters' foraging. For example, in pools or areas of slower current, darters range farther to procure food. Similarly, when flow rates are high, travel is reduced. The presence of large crayfish which will prey on darters as well as predatory fish such as smallmouth bass will affect how much darters move also. It turns out that in nature crayfish, while smallmouth prey themselves, benefited from darters being forced to hide underneath the rocks to avoid smallmouth predation. While at the same time the crayfish crawling around hunting in the rocks evicted the darters which made them become more active and available for smallmouth to prey upon. At the same time big darters will eat small crayfish, It is, as the saying goes a fish eat fish world down there.

Photos are from the great ODNR Species Guide Index, a great source on information on all wildlife.