Differences between a trout and bass
I'm certainly not the one to answer this question but perhaps if you went to the black bass sites where they discuss their fish finders to the similar level that we trout fisherman discuss the finer points of wire dimensions for Copper Johns. A few fish finder sales representative have told me that something about an air bladder that exists for a bass that trout don't have which makes the difference of a fish getting picked up on the finder. Check those message board to get a more definitive answer.