Some questions about fish finders readings?

Question

Hi, i recently bought the garmin 400c fishfinder. I have a few questions on how to translate the readings. The manual I have does not answer my questions below.

1. Is there a way to figure which direction the fish are heading?

2. Say i am in a stationary position and if i am on top of a school of fish how that would translate on screen? Would it show it as a long line because the screen updates from right to left

3. How can i distinguish the difference between a fish and object at the very bottom?

4. is there a website / book / dvd that shows you with detail on how to translate the readings?

Thanks

Answer 1

I'm no help but we have one of those also, and we have caught fish when the screen has been blank

Answer 2

I am a commercial fisherman and we very rarely ever use a sounder to track fish. they are only really any good at finding out what the ground is like that you are fishing on ie if its banky rough ground or flat sandy ground. if you go over say a shoal of mackerel it will show you like a big patch of red or blue or whatever but this could also be many other things like sea weed or very small whitebait, if you find a wreck and its showing you lots of readings then it is probably cod or pollack or even bass. but you never no for sure. Good luck

Answer 3

i`m also a commercial fisherman & with all these things only by using the devise will u determine what is what! i`v seen the screen full of red for a full watch (4hrs+) and when u haul nothing like what u thought would be there!

Answer 4

I am not familiar with the Garmin 400 but the principle is the same with all sounders. 1.Fish (apparently) face uptide in a body of water that is moving downtide.(know the tidal flows in your area) 2.Yes 3.Many sounders have a function called white(or gray)line and bottom lock which help differentiate between objects on the seabed and fish just off it.4. Not that I know of.

Answer 5

1. you need to know what direction your transducer is facing, this will help you know after a few passes you can figure it out

2.yes & they would show at different depths too

3. you can't really except with long term use experiance, and sometimes it is still not possible.

4. unknown, but if there is I am interested in it too

ANSWERERS?