Something else to ponder…

You know what amazes me most about these screen pics? The orientation of the fish to the transducer and therefore surface of the water. Stay with here: when we look at these pictures we are looking at them as if we were looking into an aquarium – from the side. That is not how conventional 2D or down imaging sonar looks at them though; they are looking at them from above. So while we see the side of the fish (if he is swimming normally), the sonar sees only the top of the fish. Try this: take your wallet and hold it up in front so that you can see the side of it. That is what you see looking into an aquarium. Now hold it so that you are looking down at it but hold it so that you can only see an edge. This is what the sonar should be seeing. Look at the picture that we have been discussing or even the School of LM Bass picture. Looks like we are looking into an aquarium doesn’t it? So doesn’t that mean that these fish were at least partially turned on their sides?

Now the last picture that Kosmo posted (should have grabbed a screen snapshot Kosmo, it would have been clearer!). This is a Di image from the Side Imaging sonar beams. These may be hitting the fish from the sides, due to being pointed at an angle, and so seeing the profile of the fish should happen more often.