The ocean can be a daunting opponent. Miles upon miles of open water stretch in every direction. The fish could really be anywhere.
Over the centuries fishermen have learned to pay close attention to the subtle clues that fish may lurk below. Disturbances on the ocean’s surface, changes in current and increased bird life are three such examples. Of course there are countless other clues, strategies and superstitions fishermen have used when trying to locate fish.
Yet in today’s technologically driven fishing world there is one piece of equipment which drastically reduces the amount of time, energy and effort spent locating fish. This piece of technology is, of course, the sonar (fish finder).
But simply having a £800 or more sonar unit (fish finder) installed on your boat is no guarantee of fishing success. As with anything else, there are sonar strategies you can start using today to dramatically improve your odds of locating the biomass. Strategically using sonar (fish finder) is, in my opinion, the #1 most important factor to modern day fishing success.
Locating the Biomass
When it comes to finding large schools of fast moving predatory fish I recommend adopting the mindset of “locating the biomass.” Most predatory fish species travel in a school, which is often part of a much larger biomass of fish in the general area. For example, you may have located what seems to be a large school of fish – when in reality that seemingly large school is just a small piece of an even larger biomass.
If you can locate a biomass of life, good fishing will ensue. The question then is, “how can I locate the biomass?”fish I recommend adopting the mindset of “locating the biomass.” Most predatory fish species travel in a school, which is often part of a much larger biomass of fish in the general area. For example, you may have located what seems to be a large school of fish – when in reality that seemingly large school is just a small piece of an even larger biomass.
Locating the biomass begins with having a general idea of where fish may be. Perhaps you know from past experience that schools of fish are likely to reside somewhere within a given bay, along a stretch of beach or on a bank offshore. This is an ideal place to start, yet you still have a lot more narrowing down left to do.
For example when fishing Cape Cod Bay (where I often fish) the fish could truly be anywhere. Cape Cod Bay is a magnet for marine life, yet the Bay encompasses 600 square miles and the fish could be virtually anywhere. How then, after deciding on a general area to fish, can you use your sonar to pin-point fish with laser like accuracy?
Locating Fish at Lightning Speed
When searching for schooling fish with your sonar (fish finder), the best strategy in my opinion is to remain in motion until you mark life on your sonar. To do this with success, your sonar must function properly at high speeds of over 20 knots. Be sure to adjust the sensitivity settings on your unit, so you can mark fish while eliminating disturbance caused by engine bubbles.
A typical fishing trip for me will involve cruising for sometimes hours on end through a large general area where I believe there to be fish holding. All the while I will keep an eye on the sonar, being sure to notice any schools of bait fish or predatory fish that I may pass over. My goal is to literally drive my boat over the top of a school of fish, with the understanding that the school of fish I mark on my sonar (fish finder) is most likely just one school of a biomass of fish holding the area.
If you are fishing a large general area, it can pay to cruise through that area in a grid like pattern. For example I may follow the 50 foot depth contour for 10 miles, then turn around and follow the 60 foot contour for 10 miles. I will work my way out deeper or in shallower until I cover the entire area before moving on.
Of course when using this method I hope to locate the biomass as soon as possible. Yet in my mind spending a couple hours without finding a single school of fish is not a bad thing at all. In doing so, I have eliminated an entire tract of ocean devoid of fish life, within a matter of a couple hours. If I had not utilized this fast paced sonar strategy, I may have spent an entire morning or afternoon fishing that area – never knowing for sure if schools of fish were even present.
Using my sonar at high speeds of over 20 knots, and cruising in a grid like search pattern has proven to be the most effective fish finding method I have ever utilized. Yet I will admit that the strategy won’t work at all, unless you have a firm grasp of how schools of fish look on your sonar at such high speeds.
What to Look For
When cruising at high speeds (granted your sonar is installed properly and sensitivity settings are correct) schools of fish will mark differently based on how large and dense the given school is.
For example in the image below you will see two distinct marks. The first mark to the left side of the image is the same school of fish displayed in the middle of the image. Yet the difference being that the “sliver” of fish on the left, is actually the same school of fish in the middle, when viewed at high speed.
You’ll also notice the side-scan sonar image below – which we’ll talk about in the next section of this post.
Because you are cruising over a school of fish at high speed, the mark on the sonar will be more like a vertical “sliver” than the big “blobs” you may be accustomed to seeing at slower speeds or when at drift. The thing to remember is that when cruising at high speeds, even the slightest sliver of a mark may in reality be a massive school of fish.
Therefore I recommend stopping and further investigating any “slivers” or any other out of the ordinary marks, that you record on your sonar when traveling at such high speeds.
Sonar Tips to Take Fish Finding to the Next Level
If you really want to take your fish finding skills to the next level I would recommend purchasing a sonar unit that comes with side-scan sonar technology. Side-scan will let you “see” off to each side of your boat. With side-scan you can mark fish that are swimming to the port and starboard of your vessel.
Side-scan does not function well at high speeds; however it comes in very handy after marking a school at high speed using traditional downward imaging sonar. A typical scenario for me is to use traditional sonar at high speed to find the biomass, and then use side-scan sonar at speeds of 2-7 knots to zone in on the individual schools within the biomass.
With regards to locating fish, learning to strategically use sonar can help shave time off locating fish, which in turn provides more time for catching fish. Remaining mobile and using sonar at high speeds to locate rogue schools and biomasses of predatory fish is a new-age technique that can help you maximize your time spent on the water.
Tight lines,
Ryan
Ryan Collins is a charter and commercial captain from Cape Cod, Massachusetts (USA). He is also the creator of the popular Cape Cod fishing blog – myfishingcapecod.com.
He can be reached via email at [email protected].
