I don't know if you fishermen are aware of this, but fish species have
a preferred temperature range.

Of course the problem is that temperatures in fresh and salt water can
vary with depth/current/tide in that order. You can correlate some
temperatures based on surface readings - it's not to hard to do.

How many of you folks do that? I ask because a friend of mine sent me
an email about his experience with his transducer which was reading
four degrees too low. That can affect a fishing trip big time.

Personally, I never even considered it thinking that four degrees
wouldn't have any effect, but apparently it does - four degrees can
take you right out of the preferred temp range for a lot of fish.

http://home.cfl.rr.com/floridafishing/temp.htm

Something to think about when your getting ready in the Spring - check
the accuracy of your transducer for temperature.