Sonar Help

[IgotWood]

Hey folks. I am new to this sonar. This is my 4th time out with it. I don't normally feel confident in anything I mark in shallow water, except for bottom topography. However, I just couldn't ignore what I saw on the screen today. I was off a point, and the bottom is mostly mud and some grass. I threw everything I had at these fish, and couldn't conjure a single bite. I then tried a few panfish jigs, thinking perhaps it was a school of crappie, or something...but no bites. I had marks like this all over the place today. Once I got out to deeper water (5'-7'), I was finding marks like this way more frequently, and they were very close to structure. Am I wrong for trusting that these marks were actually fish? Am I misreading my machine? If they were fish, what the heck could I have done to get a bite? I tried jigs, cranks, jerks, wacky worms...no bites. My machine was set on 800mhz, noise rejection on, chirp speed was set on slow.

 

[scaleface]

They are fish , hard telling what kind . That depth finder gives a nice picture . 

[slonezp]

Definitely fish. Possibly schools of large shad or small carp?

[IgotWood]

Thank you. I posted this in another forum as well. Most guys were saying that because of the depth, and the fact that I wasn't moving, these marks were likely shad in the 3"-4" range. It makes perfect sense. This is why I usually don't read the marks in anything less than 10 or 15 feet.

[WRB]

At 3' your sonar signal size is about 12", the same as a dinner plate! You should be able to see the fish visually.

Tom

[keeganzpapa]

http://fishfindersadvisor.com/hook-4/

 

http://www.furunousa.com/LearningCenter/Transducer-Beam-Angle-Calculator.aspx

 

The first link tells the angle the transducer transmits at according to what function you are using, and also the size of the cone area coverage.  You have to read the figures very carefully.

The second link is an automatic calculator of the cone area coverage according to the angle and the depth. Once you put in the angle of your beam, then the depth and hit calculate, it will automatically show the beam area of coverage. I believe this is the distance from the center of the transducer to the edge of the cone in any direction.

 

The shape of the CHIRP sonar differs from that of the down scan. The CHIRP is a cone shape. The down scan is like a flattened cone wider port and starboard and very narrow bow to stern.

 

I received the same ff for Christmas and have spent over a month finding this information, and am very glad I read about your experience as I would have reacted the same. The fish are showing a very strong return making me think they are huge, where they are only close to the transducer, but small. 

 

I look forward to reading more of your experiences, as it will probably be Spring before I get my unit out.

 

I see from your photo that you are using the 455 KHZ beam. So if you use the beam angle to calculate, at 3.5 ft you are shooting a fore to aft beam of 0-1 ft and a port to starboard beam of 4 ft.

 

 

 

 

[IgotWood]

As I said, I posted this somewhere else too. Several others replied with a thought that makes perfect sense. Because I was so shallow, the ping speed was set to slow, and the boat was not moving at all, they thought perhaps that I was marking bait fish, like shad. Because of the scenario, the returns appeared on the screen as large fish because the targets were directly under the boat for a long period of time because I wasn't moving.

 

If they truly were fish, then I walk with my tail between my legs, because I threw everything I had at them and never got bit. Very good info in the links you posted...thank you!!

[agilmorefishing]

Your electronics don't lie! The top picture is showing fish that you were either idling over, or they were moving themselves, arches are fish moving in/out of your sonars range. I'm assuming the second picture you were stationary. It is hard to tell what these fish are, bass don't necessarily group together but they will stay in the same general water column, especially when feeding. This could be any kind of fish, however crappie will definitely stack straight up and cover a pretty big column of water(i.e. 5ft-15ft). Odds are you are looking at bass, or something else that may school in that body of water.

 

[Scott F]

I used to see things like that on my sonar and spent hours trying to catch the marks I saw on the screen. I got frustrated so I bought an Aqua Vu camera so I could see exactly what I was looking at. Almost every time I saw bunches of marks on the screen and dropped the camera down, what I was actually seeing was junk like leaves that were floating, suspended in the water. 

One thing about shallow water is that fish are often spooked by the boat and will swim off to the side away from the boat so marking fish is not very common. They could have been bass but not likely.

[Darren.]

29 minutes ago, Scott F said:

I used to see things like that on my sonar and spent hours trying to catch the marks I saw on the screen. I got frustrated so I bought an Aqua Vu camera so I could see exactly what I was looking at. Almost every time I saw bunches of marks on the screen and dropped the camera down, what I was actually seeing was junk like leaves that were floating, suspended in the water. 

One thing about shallow water is that fish are often spooked by the boat and will swim off to the side away from the boat so marking fish is not very common. They could have been bass but not likely.

 

I didn't buy the camera, but I did have very clear water
when I did this test. Same thing, leaves and debris all
the way tho they looked like fish on the monitor (not the
fish symbol).

 

Not doubting you may have been on top of a lot of fish,

@IgotWood, but I know some of the reservoirs you fish 

and there's a LOT of leaf clutter every fall/winter that

comes across this way on sonar. Granted I do not have

as nice a unit as you do, but I've been supremely frustrated

at times throwing everything at ghosts.

 

Once, though, I was following a school of running shad at
NNPK, got into a position where they went under my kayak
and my sonar did register them as a moving cloud - in
about 10 feet of water. So I know the sonar works  

[WRB]

Take a look at Doc Bruce Samson Sonar DVD tutorials.

Tom

[IgotWood]

I highly doubt they were any type of game fish. I would think they would spook quite easily before I could get on top of them in 3' of water. Yes, I know debris, sticks, leaves, etc. will register on the sonar. It could have been debris. However, I'm thinking that I may have located a good school of small bait. I went back there the other day, same conditions, same setting on the sonar, except increased ping speed, I found a large school of shad in the same area. With increased ping speed, and a slight breeze to keep me adrift, they were marking as small dots, schooled tight together.