Fish Finder Training – Screenshots & Interpretations

[MrGiggles]

I snapped some photos of my Sonar on my last outing and could use some interpretations from more experienced eyes.

I'm thinking this is a tree trunk with some scattered crappie/bluegill along the bottom?
 

More panfish?

I drifted over this and wasn't sure what it was. By the time I got my phone out it had mostly passed over, but it looked maybe like a pile of lay downs or brush? Just the end of it is on the graph.

I apologize for the blurriness of this photo. Bass or other game fish suspended?

 

These were taken last Sunday on Stockton.

[J-Doc]

Definitely small gamefish probably bluegill or small crappie as you suspected. I did not see a stump however.

The fatter football arches are most likely crappie in 2nd photo.

In the 3rd photo, the arches appear as "streaks" or long arches.  This means the boat was either sitting relatively still or the fish were active and moving quickly.

In the 4th photo, yes this appears to be bass.  Again, sitting relatively still again?

 

Always remember, your sonar feeds images like a printer or on a scroll.  Think of an image like a polygraph test you've seen in movies/TV.  The roll of paper rolls out at a constant speed while the needle jumps and moves showing the testee was either lying or telling the truth.  When it detects a heartbeat increase the needle moves. 

Sonar is just like that.  It sends a cone shaped signal and returns an echo.  If nothing, it reads bottom only.  When it comes across a fish, it echos a signal back to the transducer and reads a fish like a "football" because of the shape of the fish and turned downwards at the ends due to a weaker return at the ends of the fish itself.  Upward sloping marks means the fish were probably looking upwards and crappie typically do this but bass do also.

 

Hope that explanation helped.

[MrGiggles]

The third set of numbers on screen is speed in mph. Most were taken while drifting or idling in gear.

The tree I was talking about is in the first photo, the red cylindrical mark just off center. Not sure why it didn't mark where it attaches to the bottom?

[J-Doc]

I failed to see the mph.  THanks.

Yes, when reading "0.00mph", the long streaks reflect that.  The faster you go, the shorter the arches due to the explanation I have earlier.

The red spot as you are referring to as a stump could be just that.  If not reading as connected to the bottom that indicates the scan shows the stump is at an angle.  You could go back over that spot from a different direction and clearly see it at an angle.  Hope that makes sense.

Think of sonar this way...

If you took a road cone, cut the top off or drilled a hole in the top of it and stuck it in the water and looked through it like you were looking through a telescope, that's how sonar works.  In a cone shape.  The deeper the water, the more you can see because of the cone.   You are strictly limited to the cone angle.  The lower the frequency, the wider the cone angle.  You are using a dual beam 200khz so your beam is pretty wide compared to 455khz and 800khz structure scan. 

See attached link.  Good reading here.

http://www.thetechnologicalangler.com/sonar.html

[mmirg]

Here's what I was seeing below the pothole on Bull Shoals. What do you think this is?  It went was like that for about 1/2 mile.  I was trolling and deep diving crank bait. I never got a bite.  Thanks for the info on this thread I've read the whole thing.  I'm trying to learn what my electronics are showing me. 

[J-Doc]

Based on the depth you are at, I'd say a mix of baitfish.  Could be juvenile gizard shad or threadfin.  Looks more like gizard because threadfin are usually 3" in length.  Gizard can get up to the length of a 20oz bottle of soda. 

[mmirg]

It's seeing stuff  like this that makes me  think my sonar is acting up.

[176champion]

Would this be bait fish by chance in these pictures...Helix 7

Also there are vertical lines up and down the screen, kind of looks like bubbles coming from the bottom and streaming upward at times..what does that indicate?

 

[J-Doc]

Really hard to say.  

 

Lines drifting upward at a steady pace and frequently sometimes indicate an underwater spring or upflow. Sonar can pick that up. 

[LittleRedFisherman]

J doc.  My lab chewed the cable into that goes to the transducer on my helix 9.   There are several wires in there.  Gonna try to splice and shrink wrap it.  Should I be concerned about doing this and being water proof and all.