Does Sonar scare fish?

[hitthebricks]

I was wondering if the pulse from a transducer scares the fish away. It seems to me that whenever I locate fish on a break or reef or where ever, after a very short while they have moved away from there. Would the sensativity setting also have a cause and effect with this? My tranducer also has dual freqencys, 200/83khz, what situations are they best suited for? HTB

[Big R]

I don't think these units produce enough power to have any effect like that on fish. You must remember fish are always on the move they aren't going to stay in one place for long.

[Valv]

This is an interesting question and I asked it too many years ago when FishingMinneosta.com was just born, in fact it was one of my first questions.

Anyway I believe (now) the clicking of the transducer does not scare fish, your propeller, boat shape, motor etc scare the fish more than sonar.

[Surface Tension]

I don't think its scaring fish either. About the dual frequency ducer. Use the 200 kHz as your primary, it'll have much better resolution, definition of targets and bottom. The 83 kHz has a wider cone angle, will go deeper but you loose a lot of definition.

Trollers on Superior like the dual frequency because you can pick up downriggers weights that blow back with the lower kHz(wider cone angle) transducer. Typically you use them both on split screen.

[Dahitman44]

Good points -- But I wonder if a vexilar or underwater camera can "spook" some fish in the winter. I have seen evidence both ways so I don't know.

[Jim Hudson]

At times for certain species, I do believe the sonar can really wreak havoc on fishing...

For shallow water trout, especially through the ice, I believe a high ping output of a transducer can scare fish... Just an observation I have seen... As some ducers really ping hard and some have low output and do not have much or a pronounced ping...

Like I said, just an observation.. Nothing concrete...

[wishing for walleyes]

A few years back taking 2 of my daughters bobber fishing in the boat,we fished a channel between 2 lakes.Every time a boat would come by we casted right behind him and the walleyes would bite then and only then.They liked the stirred up water.My daughters even got thier limits doing this.There was no current left in the channel as the water levels had went down.All of the walleyes were anout 2 #`s

[hitthebricks]

I don't think of sonar as noise but as a pulse. If you hold your hand under the tranducer you can really feel the pulse as it moves. I guess that would be ping, when you turn up the sensativity, does it ping harder or faster? Another question is, didn't they crank the power all the way up on the sonar years ago in shallower water to scare the fish out to the planner boards when trolling. Thanks for the help! HTB

[BobT]

I've wondered about this myself at times and I have come to believe that the hulking boat hull overhead is more likely to spook the fish than the pinging from the transducer. For sure, the pinging is about 10 times stronger through the water but that also means the fish hear it long before the boat gets there and they aren't running scared. It's when the boat goes overhead that the fish will tend to spread out or perhaps even scatter a bit. I believe that is why long line trolling and planer boards can be effective.

Bob

[Surface Tension]

The gain/sensitivity doesn't change at the transducer, its a constant. When you turn up or down the gain you control the receiving end on the return ping.

[skunked_once]

It didn't scare the ones I caught but it must have scared the ones that I didn't catch