Locating fish is probably one of the most challenging aspects of a fishing trip, especially when you visit foreign waters which you are unfamiliar with. Anglers who frequent fishing spots on a regular basis over an extended period of time gradually accumulate a vast amount of information regarding fish behaviour, feeding patterns, concentrations etc. which enables them to be more successful than others.

However, having said that, even the most astute angler is unable to visibly pierce through layers of water, or ice, in order to see exactly what’s going on down there. This is where a fish finder can save lots of guessing time as well as provide a modicum of success on days which would otherwise turn out blank. Fish finder won’t automatically make you catch more fish, but they will certainly assist you in finding out where the fish most likely are.

In this article I will take a brief look at different types of fish finders; how they work, where they can be employed and which ones are the best for specific activities. I trust it will be a great help to novice anglers.

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#1 – Fishing from a Boat or Kayak

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#2 – Fishing from the Bank

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#3 – Ice Fishing

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How Do They Work?

When we mention fish finders we talk about a device used for locating fish underwater. This is done by the detection of reflected pulses of sound energy, also known as sonar. The reflected sound is displayed graphically on a monitor which allows the person interpreting this information to locate various things underwater. It may be submerged structures, bits of debris, the bottom itself or schools of fish.

Fish finders work on the principle of compressed high-intensity radiated pulses and this technology (CHIRP) originated, like so many others, in the military from where it gradually moved into civilian applications.

The sonar transducer is the device that sends out sound waves from the fish finder. The transducer changes electrical pulses into sound waves and back again. In this way the fish finder can “read” or interpret the information under the water surface.

What Type of Fish Finder Do I Need?

#1 – Fishing from a Boat or Kayak

Venturing out in a fishing platform on any body of water, whether it be lake or ocean, puts the prospective angler on a vast featureless plain with very few cues where fish may be. Traditional fisherman had a myriad of ways to try and plot underwater structure (or lack thereof) in order to determine where to find fish.

I remember as a kid going out with an old fishing boat with an inboard engine put to sea at a small seaside village called Still Bay in South Africa. Those grizzly salted fisherman had different landmarks as points of reference of where the productive reefs were located. For pelagic species they scanned the horizon for predatory birds dive bombing bait fish indicating schools of predatory fish underneath.

A modern day fish finder takes most of the guesswork out of the equation and enables even the novice angler, trained in deciphering the images on the monitor, to establish where they should focus their fishing attention.

As a student I used to accompany a friend of mine to their holiday home on the West Coast of South Africa at a place called McDougal’s Bay to indulge in some snoek fishing. They had a 14-foot ski craft fitted with a fish finder and during the Easter holidays massive shoals of snoek () migrated close to the shore on their annual southward trek.

Some days a cursory glance at the monitor of the fish finder showed a continuous solid image giving the impression of an extended reef when, in fact, it was just an immense shoal of fish, between two and three feet in length, passing beneath our craft.

Top Tip

With the help of electronics you now can scan the bottom and, if in possession of a GPS, you can even mark a very productive area for future reference. If you are fishing on a lake you can also memorise some landmarks in order to return to that area in future.

#2 – Fishing from the Bank

Most people think of fish finders as something attached to a boat or kayak, but portable fish finders are gaining more and more popularity in fishing parlance. Even if you are an experienced angler who have been fishing a specific lake for a couple of years, your knowledge about the underwater water structures and topography may be limited. Aren’t you curious why exactly fish tend to prefer those “honey holes”?

All seasoned anglers know that, in order to hunt fish successfully you have to be aware of the locations they prefer to hang out. Most predatory fish tend to hover in places which give them ample cover to launch a surprise ambush attack. This is true for largemouth bass, smallmouth bass, striped bass, pike, snook and trout.

Any sizeable obstacle in a body of water will provide such cover and that’s why an angler should always be on the lookout for such obstacles be they rocks, fallen logs or sand. It is important to note that predatory fish are, mostly, great opportunists and will seek places that fit this description as close to the shoreline as possible.

Due to the constant movement of various currents in a river or the impact of a sudden influx of water into lakes because of heavy rains, you are able to find considerable fissures and rifts near the shoreline which can also provide excellent cover for opportunistic predators.

These underwater ravines can change the directions of currents (especially in rivers) which, in turn, may confuse and disorientate smaller fish swimming in its vicinity. Wily predators instinctively know this and that’s why these spots are popular venues for them to congregate

Top Tip

If you frequent a lake quite often start “drawing a map” so to speak with your fish finder. Attach the fish finder to a strong piece of monofilament and cast it out from the shore. By casting and retrieving slowly you can methodically map out all your favourite fishing spots in order to ascertain where exactly the structures and/or underwater holes are that may contain fish. Once they are located, mark them.

Be aware, however, that any body of water is a dynamic system which may change from year to year or season to season, depending on weather conditions and the influx of water. It will be prudent, therefore, to do this mapping exercise on a fairly regular basis.

As with human high ways, there are certain underwater channels which are, more often than not, very hard to detect with the naked eye from the shore. These underwater “high ways” are the natural travel routes for fish which provide a convenient way for fish to get from one part of a lake or river. Most of the times they consists of logs, boulders, sand banks and other underwater structures.

A fish finder is the ideal device to detect channels and, using the method above, those channels should also be identified and marked.

#3 – Ice Fishing

The whole concept of Ice fishing and the methods involved have undergone drastic changes over the last two decades. For modern day ice fishers mobility is the key factor and the days of drilling holes, waiting patiently in the hope that a fish may swim by are almost something of the past.

Armed with light, fast and powered augers and a portable fish finder an angler can conceivably drill and check hundreds of holes in a single day. If the fish stop biting at any given location an angler can now simply move to the next spot and check it first with their fish finder. If things look positive a hole can immediately be sunk, alternatively, the angler moves on until fishing activity is located.

Boat fish finders can be used for ice fishing, but portable fish finders are just more convenient for this purpose. Keep in mind that you still have to drill a second hole in the ice exclusively for placing the fish finder in. Once you have attached the fish finder to a rod or line you can connect it to a phone or tablet and then lower it down into the ice hole.

Top Tip

Make sure that you check on the fish finder regularly to prevent it from being swept away by currents and also check regularly that the ice hole doesn’t freeze over. If the ice hole is not big enough the ice sheet may impede the sonar of the transducer. If this occurs you will experience a lot of noise as well as false readings on your monitor.

Most fish tend to operate in schools and these schools of fish are constantly moving in search of food. This is an important fact, because a fishing hole may be provide action for 10 to 20 minutes after which the fish just disappear.

That doesn’t mean that specific school of fish won’t visit that location again within maybe the next hour or so; that’s why it is important to mark these spots in order to regularly check up on them in future. There are definitely “fishy” spots in every body of water and it will enhance your catching rates if you frequent these areas on a regular basis.

The more experience you will gain in using your portable fish finder the better you would be able to understand which phenomena may influence the workings of that device.

Fish Finder FAQs

Where Do Bass Tend to Spend Their Time in a Lake?

Always keep in mind, when on the lookout for bass, that these fish are heavily structure orientated in their behaviour.

They tend not to hunt in the open waters, but rather hide away waiting patiently in ambush in or nearby structure like a submerged log or a clump of reeds.

Any unsuspecting prey species venturing to near its hiding place will result in a lightning strike attack by the concealed predator which will pounce upon its hapless victim in a blink of the eye.

Therefore, expect bass to hang around different types of water plants, submerged logs and rocks as well as any manmade structures (like jetties and moorings) which are part of their environment.

For the novice angler visiting a new angling spot for the first time, a good strategy would therefore be to actively search for any kind of visible structure. Focus on casting your lure as close as possible to said structure and be prepared for any eventuality.

Failing that, employ your newly bought fish finder to locate those lunkers!

What Are the Key Topological Features of a Lake for Fishing?

Always be conscious of the fact that most freshwater fish species tend to congregate around structure; either as a form of protection or to procure food. Therefore the focus of a diligent angler should always be to look for those structures and concentrate his fishing efforts close to them.

The availability of food and protective cover are two of the major reasons why fish visit certain areas. Any locations where streams, creeks or rivers enter lake as well as deeper holes and structure close to the shore (such as aquatic vegetation) are normally places where a prospective angler can expect to find fish.

What Are the Key Topological Features of a River for Fishing?

Although the river currents bring most of their food to them, fish in rivers will also seek places to shield them from the force of the current – thus the perceptive angler will always be on the lookout for places where the current, seemingly, has the least influence.

Any obstacle in the stream will provide such cover and offers respite from the relentlessly moving water. Keep therefore a constant eye open for structure like rocks, fallen logs or sand banks.

Depending on the size of a river, its gradient as well as its specific course it normally forms a series of holes or pools where the water slows down dramatically and which are obvious holding places for fish, especially bigger specimen. These are the key areas to employ your fish finder, because, as a general rule, the bigger fish will claim these prime estates for themselves.

Final Thoughts

Ok folks, that’s it for some basic information regarding fish finders. I trust you found it helpful and informative. As always, any comments and criticism of this article are more than welcome.