Tips for Finding Fish in the Sea

April 05, 2019

Sound navigation & ranging (sonar) fishfinding systems help scientists and fishermen who try to identify and locate fish in the deep sea. This type of sonar unit functions just like the other kinds of sonar. 

A transducer is usually dragged by a boat or attached to the boat to propel out any acoustic signal. The signal reflects away from the air in a fish’s swim bladder and if the fish has no swim bladder, it reflects on the fish itself. 

The return signal is picked up by a computer which changes the signal into images of fish on a screen. These images usually look like arches due to the fish’s movement via the acoustic energy’s beam. 

Fishermen and scientists who use this system function at extremely high frequencies of about 20 kHz to 200 kHz. The peak of the frequency range provides the target’s details. It can also separate 2 fish into separate arches.

The lowest end of the frequency’s range provides a bigger depth range, although fewer details can be shown. Apart from just locating fish, the most modern fish finders have the ability to distinguish between various fish species. 

Scientists have come up with improved fresh techniques for easier differentiation between the different marks which are also known as echo signatures. Every fish has a distinctive shape and size of its own swim bladder. 

The dissimilarities of swim bladders bring about variations of the return echo of the solar signal. Therefore, the echo signatures of certain species can be established and used to recognize and differentiate fish.

It is important to note that the differences in the structure of the echo signature are seen between different species while the differences between the control and the free swimming measurements are negligible between various species. 

The echoes which are quantified at the surface and under managed circumstances are employed to recognize various fish species at different depths. This specific kind of acoustic data is crucial for fisheries surveys. 

It is a useful method particularly when one is interested in learning about the deep sea bottom fish species. Most fish species live below the normal diving depth, hence, studying them can only be done using fishing gears or submersible vehicles. 

Acoustics offer supplementary means to enable scientists to recognize the bottom fish and observe them in their ordinary natural environment. Understanding the fundamentals of how sonars work plus how to read it is key in finding fish species.

To find fish, do not assume that each fish you’ve marked is straight under you’re your sonar. You should instead think that they’re just somewhere inside a cone that spreads out under your sonar. 

Note that the deeper the depth marked, the broader the area it might be in. If a fish is shallow, know that the fish is more or less straight beneath your sonar. This is likely to happen if you are using a very narrow beam. 

If a fish is very deep, it is possible that it is in a very wide area and further away from your sonar’s location. Always make use of the broad beam to find the fish’s general area and switch to the narrow beam then scan the area to find the accurate location.

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