Fish Finder Basics

I think that fish finders are perhaps one of the least understood technologies with new kayak anglers and therefore leads to a lot of questions concerning purchase and use of them. With all the different bells and whistles available concerning fish finders it can be a daunting task for the person considering their first purchase of a unit for their kayak. I will make an attempt here to answer most of the initial questions most have regarding this subject.

Sonar: This is the traditional type of unit; it shows great detail and can come with a grey scale or color display. This unit shows fish and bait movement very well. One down side to sonar is that structure at deeper depths may be obscured where you may not be able to see the bait or fish suspended in the cover. This unit works very well with a shoot-thru-hull transducer mounting.

Down scan (DSI) and side scan: These units give almost a photo quality snapshot of structure. These are great for seeing into what is in trees and any other thing that is sitting on the bottom. The down side is that fish are hard to distinguish and you cannot see movement of fish on these. These transducers need to be in the water as they lose a lot of signal quality if the transducer is mounted in a shoot-thru-hull install.

Lowrance Has come out this year with hybrid Dual Imaging (HDI) This unit combines the traditional sonar frequencies with the higher frequencies of Down Scan and GPS. It is able to display both sonar returns and the increased structure detail of DSI. It is even able to superimpose the two screens over one another (Hybrid) to give a very different perspective than just one view or the other.

What does the frequency of the transducer mean?
Most transducers come with a wide or narrow beam unless you get a dual frequency transducer which you are able to select the frequency you want to use. The easiest way to explain the frequency range of transducers is to imagine a flashlight with an adjustable beam. You can fan the beam out into a flood pattern and illuminate a wide area for a short distance. This will illuminate a larger area but show less detail. Or you can narrow the beam up to a spot. This will illuminate a smaller area but travels a greater distance and shows more detail. With transducers a narrow beam is great for deeper water and a wide beam is great for shallower water. Another great thing about dual beam transducers is when you are fishing next to someone in another yak you can select a different frequency than they are using so there is little to no cross talk between the two units.

What is the difference between a color screen and a grey scale screen?
The color screen allows different densities to be represented by different colors. On the Grey Scale units, most use different shades of grey, however the difference in density is harder to distinguish. I have found that most color screens are brighter and easier to see with the sun glaring off the screen.

The biggest mistake I see people make is to turn on the fish symbol feature. The problem with using this feature is that in my opinion most of the fish symbols on the screen are false returns. It will keep you fishing and area where there may not really be any fish. Do yourself a favor and turn this feature off and learn to read what you are seeing on your screen. Some units like the hummingbird will display both the actual returns with the fish symbols superimposed over the return and this is ok and will help you to determine what is actually fish and what is not. However if your unit stops displaying the actual return and replaces it with the fish symbols then don’t use it. You will thank me later.

Keep in mind that you do not need the most expensive unit out there, however you get what you pay for. Ask your self will you actually need GPS? If you are learning to read a fish finder start out on the low end price wise.

In reality the information that you need to gather from your fish finder is not always fish. Yes I said it...There are a lot of fish I catch that I never saw on my unit. However because of the information I did use to select the area where the fish were I was successful. It's all about information, so some of the things I am looking at is structure, bait in area, water temp, depth and bottom features. You do not have to see fish to catch fish. Remember you are using a flash light and the fish may be just outside of your beam...close enough to see your bait but not close enough for you to see them.

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