Sounder Readings... What do they mean?

[mini696]

Can anyone point me to a place I might find detailed descriptions of what different objects look like on a fishfinder/sounder??

[SeaHunt]

Start here .
http://www.ausfish.com.au/cgi-ausfish/board/YaBB.cgi?board=Tackle;action=display;num=108798090 9
And can also read this ,
http://www.lowrance.com/Tutorials/Sonar/sonar_tutorial_01.asp
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