Northern,
Since the transducer is underwater, you typically
don't have ice build up problems. Ice can build up
on the cable where the air meets the top of the water.
It can be left on the cable since it does not affect the
dept finder operation normally. This ice build up can
usually be broken off with your hand quite easily.
You may experience ice build up if you move from
hole to hole on a cold day.
A tip might be to spray some silicon spray on
the transducer and cable where it enters the water. I
have not needed to do this, so I am not sure these sprays
can degrade a transducer or cable.
Good Luck,
BATMAN