Fish and electronics

[LGF]

I’ve been wondering a long long time about this. Remembering how we got told be quiet when we were kids when the adults were “Papgooi-ing”.


In another thread concerning sonar, sound again came up and I thought of getting to the bottom of the sounds we make useing electronics and so forth.


Here’s an interesting, but not ultimate or scientifically proven, but nonetheless interesting read:




Does Noise Effect Fishing?
FISHING TIPS By Anthony Contreras
November 30, 2017

​Scientists and most experienced anglers agree that fish can hear. But, the question is which sound do they ignore, which attract them, and which repulse them? Screaming or loud talking will be barely noticeable to the fish underwater since sound doesn’t travel well between water and air.

However, sound that occurs underwater travel fast and it is loud. If you are jumping up and down in an aluminum boat, it will scare the fish. They feel vibrations through a system of lateral lines that goes the length of their bodies, water pressure changes, and movement.​Depending on the size of the fish, they will react differently to the same sound. A huge one might ignore it, the large one might attack, and the small one will probably flee. That is because they are curious but also frightened.In this article, we answered questions about sound and fishing that will help any beginner or professional to avoid noise that will scare away fish.

If you want to know more all you have to do is read on.

Hearing
Via two sensory organs fish can sense underwater sound. It includes a lateral line that is located on each side of the fish’s body from the caudal peduncle to the gills. The other organ is otoliths that is found in the inner ears.

Fish uses hearing to avoid danger, engage in courtship, locate schoolmates and find food. Of course, that varies with the noise level and with each species. Being able to hear well in the waters where the visibility is very low is a significant advantage in finding food and avoiding danger.

Grunts and drums will listen for that appealing sound such as ‘’snapping shrimp’’ if the visibility in the water is reduced.






​Behavior
Some experts claim that some of them can respond to sound, for example, Bluefin. In their studies, they used this particular one and trained it to react to the noise of food being placed into the pen. When tuna hears that sound, they rush to the exact point of the noise every time, even if there was no food.

These fish can hear a noise that has from one hundred to eight hundred hertz frequency range. But, when they hear some sound that has a low-frequency range, they can get scared. On the other hand, when they consistently hear the same noise they can get used to it.


Noise
It is not easy to hear a sound underwater as you might believe, even if it travels faster in water. At night some species become more active so the background noise level will rise. The sound that fish might hear needs to be above that level.

Lots of stuff, both human-made and natural produce sound underwater including sport-fishing boats, oil rigs, ships, marine life, and waves. All of these noises will interrupt their hearing, and it might be difficult for them to distinguish one particular sound from the other, especially if it comes from distance.

We said it earlier that fish can hear the frequency sound from one hundred to eight hundred hertz range which is low-frequency one. The outboard running engine can emit the high-level frequency sound from one thousand to five thousand hertz range. That means they maybe won’t be able to hear these sounds good enough.

On the other hand inboard one, will hear because it creates a sound that is within their auditory senses range.

"One of the loudest sounds made below the waterline by most other engines — electric trolling motors included — is prop noise, directly related to prop speed. In other words, slow down. You can significantly cut the level of noise simply by backing off on the throttle. Another noise no-no you create with your power plant is the "thunk" of shifting in and out of gear. Again, this metal-on-metal sound travels well underwater, and fish don't like it." according to Boat U.S. Magazine


Does Noise Attract Fish?

Some researchers claim that it is the shadow of the boat that attracts fish much more than sound. They also can be drawn by the shadows of some things such as floating debris, oil rigs, weather buoys, and fish-aggregating devices. Most of the anglers think noise that is produced by a boat will have a negative impact on them and that they will swim away.

It produces pressure waves created by wakes and spinning propellers, exhaust noise, engine vibration, and adding that to many more sounds in the water. We came to the conclusion that they aren’t going to be happy when the level of noise goes high.

"In the first test, reefs with sound collected 325 fish, compared with 108 in silent reefs. A second experiment had high-frequency noise, low-frequency one, and silent reefs. Reefs with high-frequency sounds attracted 1,118 fish, the low-frequency reefs 1,171 and the silent reefs 657.The researchers say their finding raises the possibility there may be damaging effects from human-caused noise, such as that from shipping and drilling. In addition, however, the discovery may show fishery managers a new way to attract fish to restock depleted areas." according to a team of researchers led by Stephen D. Simpson for the Los Angeles Times.







​​​
Avoid Loud Noise While Fishing

Do you know what happens when you knock on the one side of the aquarium? Well, fish will get scared and swim right to the other side. Try to apply that same principle while doing this activity.

When you create some sudden noise, like stomping your feet, dropping a sinker on the deck and slamming hatches will scare off fish. So you will become more successful while fishing if you can stay silent. If you need to make some noise try to make that constant level sound.

This way, they will get used to it, because it will become the part of their environment and it will not bother them after some time. You need to remember that everything you do on the boat will create some noise that will travel through water. So it is best to stay as quiet as possible.

When you are diving, if there are some people above the water you can hear them talking. So, we can assume that fish can hear them too. If you want to catch one that has a strong hearing, like white seabass or redfish, make sure your conversations are minimized, especially when fishing shallow or flats.

Try to be as quite as possible. This way you won’t scare them away, and you will have more significant chance to catch one of them.

[bassbug]

Good read, interesting.
Ever got to know Buck Perry? He trawls for bass and has many followers. Absolutely no worries about engine noise even when trawling shallow waters. I beleive the fish that hunt are inquisitive and will investigate or keep an eye out for it. If we worry about sonar going tick tick then might aswell put any lure with rattles away 

[LGF]

Sorry never got to know him but I agree. What is interesting is the frequencies and how that might affect different sized and species of fish, might be interesting to which are bad and good frequencies for ones target species!

[colin]

  great read 

[bassbug]

How's this, spent most of the weekend with club members at rietspruit dam near kriel, a colleague pitching into a jetty, meanwhile, a very noise pump working directly above it , two jetskis playing about, collecting and dropping off passengers on  a nearby jetty. Baaaaam, he sets the hook into a foot long bass, I beleive he took two fish from there. Do fish become accustom to noise,  I think so.

[LGF]

Check this vid regarding constant sound from the transducer over a bunch of fish, no other sounds like boating etc etc.

This then begs the question, how much does sonar sounds affect Bass, or other species for that matter?

https://www.youtube.com/watch?v=LbzGVM9fz1U

PS apparently its the low frequencies that could affect them adversely and not so much the high or ultra high frequencies.

[Visenvryheid]

That the right link to the video you are talking about ?

[LGF]

That the right link to the video you are talking about ?

That be it Captain.

The vid concerns settings to the sonar to be able to see the fish come up to the lure, however he’s got the settings at warp speed, thus blasting a higher rate of sounding into the water, pretty sure he also has it on the frequency that is suppose to irritate them, but you see them coming off the bottom to investigate the lure, can’t remember if he actually manages to catch one, but beyond the settings of the fish-finder, the video shows that they’re either used to the sounds emitted by the fishfinder or it doesn’t bother them as much as one would think,

[Visenvryheid]

Found this one looking for the "right" video haha..

https://www.youtube.com/watch?v=_WhyV_OTwRY

Pretty much sums it up, the frequencies we use are too high to really affect them, banging on the deck or turning motor on or off on the otherhand they hear...interesting..

[LGF]

Found this one looking for the "right" video haha..

https://www.youtube.com/watch?v=_WhyV_OTwRY

Pretty much sums it up, the frequencies we use are too high to really affect them, banging on the deck or turning motor on or off on the otherhand they hear...interesting..

Thanx for that clip, think it's moving in the right direction as far as losing the fear of sounds from electronics scaring the fish off. Interesting how voice (speech) is also not considered a real issue, when we grew up with a SHOOSH or a pinch on the leg when we were talking too loud next to our parents fishing.

[John F]

I guess that was more to do with not annoying the grown ups

[LGF]

I guess that was more to do with not annoying the grown ups

To a point  but they truly believed that kids (people around) talking loud would scare the fish off. I think this originated from them hunting in the veld imho