Advances in fishing electronics have been moving forward by leaps and bounds in the past few decades. Keeping up with technological innovations is a challenge, even for a techno-junkie such as myself. Sonar, imaging, and GPS have given anglers unparalleled access to what is going on below the surface of the water. However, a decade spent selling fish finders in the retail business taught me a few things. One, many anglers struggle with understanding the different features of modern fishing electronics. Secondly, many anglers are paying for features they simply don’t need or use. If you are buying your first fish finder or looking to upgrade here is a quick course on the features you might look for.
How It Works: Sonar
The majority of anglers rely on sonar. Whether you spend the majority of your time trolling open water or hovering over structure you will find sonar useful. Sonar is useful for identifying your depth, locating fish quickly, identifying the depth of fish, and can provide information on the types of bottom substrate beneath your watercraft. Sonar works by generating a signal that travels outward from your transducer in a cone shape. The signal reflects off surfaces and travels back to the transducer. Your fish finder then translates those reflections into a visual representation. Harder surfaces, such as rock, will reflect more signals than soft surfaces, such as vegetation. The hardness of a surface reflection is often represented by a color gradient that you determine on your fish finder’s settings. Using the color and shape of the return an angler can interpret what the benthic or bottom structure of the lake or river they are fishing looks like. Sonar signals bounce strongly off of air which is why fish with large air bladders show up extremely well on fish finders.
Most modern fish finders broadcast in alternating low and high frequencies. Lower frequencies produce a narrower cone that better penetrates deeper water whereas higher frequencies produce a wider cone that is better at resolving fish and structure in shallow water. Many fish finders will automatically use the best frequency depending on your depth or will cycle back and forth to generate the best signal. However, anglers can select particular frequencies that best suit their fishery and may even opt to buy transducers specific to the types of fishing they do. However, sonar does have several weaknesses. First, due to the narrowness of the signal cone, it is very poor at detecting fish shallow and under your watercraft. Secondly, because it is compressing a three-dimensional cone into a single dimension it is very difficult to separate fish from structure or multiple fish or bait fish from each other. Lastly, learning to interpret sonar output takes time and can be especially challenging for color-blind individuals.
How It Works: Down and Side Imaging
For those anglers that fish structure, whether that be brush piles, weed beds, or rocky reefs, you will find imaging useful. Imaging fills the gaps in sonar’s weaknesses. Unlike sonar, imaging is generated by your transducer generating a razor-thin high-frequency signal. These imaging frequencies can be directed downward, for down imaging, or out to the side, for side imaging. This data is then used to generate detailed and lifelike images of the structure below or off to the side of your watercraft. Unlike sonar images which can be very nebulous and confusing, especially around layered structure, imaging results are much easier to interpret. A tree looks like a tree and rocks look like rocks and so on. Additionally, fish can be separated from structure much more easily.
Imaging uses a high frequency and thus has limitations in deep water applications. In general, I find it most useful down or out to 100’. If you spend a lot of time targeting structure directly under your boat then you will find down imaging especially useful. Side imaging is useful in quickly locating structure off to the side of your watercraft and measured distances on your fish finder unit will allow you to cast at those targets. I’ve also found side imaging to be helpful in locating schools of suspended fish off to the sides of the kayak when trolling in open water.
How It Works: GPS-Enabled Fish Finders
GPS-enabled fish finders provide a wealth of information to any angler. Coupled with bathymetric depth maps GPS allows you to identify and navigate to potential fish-holding areas. Waypoints and tracks of your movements can be saved for future reference as well. Additionally, many fish finders like the Humminbird Helix have advanced features such as Autochart Live that allow anglers to build custom detailed maps of their local body of water. For anglers that troll GPS units provide real-time troll speeds. Finally, GPS can assist in safe navigation to and from your favorite fishing spots.
Advanced Fish Finder Features to Look For
In just the past few years, even more advanced fish-finding features have emerged. These include Humminbird’s 360 imaging which gives you complete imaging all around the watercraft. Additionally, live sonar and live imaging are now available on many fish finders. Live sonar/imaging gives you real-time direction target separation and you can watch fish chase your lure or bait and in some instances you can identify fish species by shape. These advanced features require specialized transducers and cost more but when used correctly can help put more fish in the boat.
