There’s More To Sonar Than Finding Fish

01 Feb There’s More To Sonar Than Finding Fish

Sonar units are often referred to as fish finders. Well we’re firm believers that sonar doesn’t actually “find fish” but gives you information that allows you to make decisions as to where fish might actually be. And hey, if you make a decision to go to a certain location and you happen to mark a fish at depth, that’s an added bonus. In all honesty, there’s noting quite like coming across a bait ball covered with slashes, dropping a bait to the fish and playing them like a video game – it’s totally addictive. Lets discuss the information your sonar unit is telling you other than if there happens to be a fish below your boat. But first, lets consider one thing:


Being consistent in your settings is vital. Why? So you can get to know what your sonar unit is telling you. Different lakes and water bodies will be as different as day and night. Consistency with your sonar unit familiarizes you with the details. When you get your unit, get familiar with it before you need it. Get out, go fishing for fun and figure the unit out. If you are consistently changing the fundamentals of your unit, it’s increasingly difficult to interpret consistently what crawls across your screen.


Around the world, fish relate to temperature either positively or negatively. Knowing ideal temperatures for the species you’re targeting is research that will help you before you event launch your boat. Do a little bit of homework. For Example, smallmouth bass are a cool water species vs. their largemouth relatives. Fishing summer smallmouth bass in 80-degree water is going to yield you zero. If surface temperatures are high, you’ll have to go deep for species such as smallmouth bass to find the cooler water. Conversely, in the spring, if your regulations allow, surface temperatures in the 40’s will push bass shallow in search of warmer water and food. Your sonar will tell you what the temperature is at the transducer and often will show you on-screen where a thermo cline (drastic change in water temperature) is in the water column.

Fish Finder Thermocline


In my opinion, depth is a form of structure, and locating optimal depth for fish is key in getting more fish to bite. FLW bass touring professional JT Kenney once won $100,000 in a tournament on Florida’s Lake Okeechobee. The secret to his success was a 6-inch to 1-foot change in depth he found in the shallow bowl shaped lake. All the fish he caught to win the tournament were in the “deep” part of the lake – a change in depth by mere inches. Sonar is vital to detect and see those subtle or dramatic changes in depth that just might hold fish – of any species.

Fish Finder Drop Off

You can see the fish in the sonar unit above are clearly relating to the drop-off.

Other structure:

It always amazes me how excited offshore fishing mates and captains get when they spot anything floating in the ocean, be it a palm leaf, discarded bucket or a log. They get excited because anything other than water in the ocean is considered structure. Generally, structure means fish. Small baitfish will be attracted to the floating structure, which will attract larger fish and so on. I have dived below a bed of flotsam (seaweed) in the ocean and seen fish as small as my thumb and fish well over 50lbs all relating to a simple piece of structure. Well the same thing can be found sub surface on your sonar. We mentioned consistency earlier; this is where consistency might be of the most importance. Sonar, and being able to consistently interpret what it’s showing you will allow you decipher structure, which will, in turn, allow you to catch more fish. The difference between sand and rock, seaweed and submerged brush, and even suspended fish all can be determined with your sonar. There are some anglers out there that can tell fish species and even feeding behavior using their sonar units. It really is a window to the world below your boat. But you have to understand what it is you’re looking at.

So be consistent, get intimately familiar with your sonar unit, use it in as many applications you can and learn to trust what it’s telling you. That, there in itself, is a great way to get started in figuring out how fish relate to temperature, depth and structure so you’ll know where to cast.