Depth finder question

[MN Mike]

I have to ask this question just to see if it is just me or is this something other people expierence too.

I have a Raytheon 365L DepthFinder, when I use it on my local lake, which is very clear, and for the most part, a firm bottom lake with sand points and what not, I can mark fish in the water pretty good, I can usually watch the fish move from deep water in the late afternoon to the shallows in the evening when they begin to feed.

When I take the unit to Lake of the Woods, I can still mark a few fish BUT not near the numbers a person would expect, especially when your catching bunchs of fish but hardly anything is showing up on the finder. I mean we will be getting double headers and what not but not a fish is showing up on the screen?!

So I guess for the most part my question is this, Would there be something in the make-up of the lake that would cause this?

Just curious.....

[Surface Tension]

There are a lot of things that can effect your readings. Water temp,Depth,cone angels, bottom hardness,gain setting, speed,suspended particals ,time of day.
Fish lay tight on the bottom to rest and because the bottom is cool. Thus making them hard to ping with your sonar. They are there you just cant see um.