Striped bass are known to be line shy.  When you couple this with the need to use a strong and impact resistant setup due to
the power hitting nature of their strike, choosing monofilament for striped bass fishing can be tricky.

In particular for downline fishing, we use about a 15 pound test main line.  We prefer either the clear Berkley Big-Game line in
15 pound test or the red Cajun Lightnin' in 14 pound test.  

The red Cajun line is interesting as red is the first visible color to disappear underwater (sometimes as little as three or four
feet underwater).  We sometimes like to use it for this reason and the phenomenon has been confirmed by divers we know.  
The red Cajun Lightnin' is a copolymer formulation which makes it quite easy to work with.  By the way, the Gamakatsu hooks
we use are red for the same reason.  It's this low visibility advantage that the red color provides in line and terminal tackle that
is the motivation for using it.  The concept that the red color simulates a "bleeding bait" is of course unsupported and not likely
a factor.

For leader material, a clear fluorocarbon material specifically designed for leader material is preferred.  A seven foot leader
joined to the main line with a barrel swivel serves the purpose.  See our link on the Fishing Page to How To Rig A Downrod for
more details.
Line Considerations for Striped Bass Fishing