Granbury and Cottonmouths

Question
I have property on Lake Granbury.  The property is heavily wooded and has 300 feet of shoreline.  I have waded the entire shoreline many times pulling out debris and making improvements.  I have swum it often.  Part of the shoreline is undeveloped with native cattails and grasses.  You can imagine that it appears to be heaven for Cottonmouths, or, as we called them where I grew up in East Texas, Water Moccasins. I am very familiar with these snakes and I know where they live.  If they were on my property I would have run onto them.  Yet in ten years of exploring not only my property but the entire lake, I have never seen a Cottonmouth.  I have no explanation for it, but someone once told me that Lake Granbury is slightly saline because the Brazos River flows through salt deposits on its way to the coast.  They told me that the Cottonmouth does not like the slightly salty water and so does not hang out there.  Is there any truth to this?  Ever heard it before?  People tell me that they are present in the creeks and tributaries that run into the lake, and that would make sense because that water flows into the Brazos, not out of it. What do you think?

Answer
Hi George

I would say that the local explanation is plausible but I know very little about the area.  Lake Paunchatrain in New Orleans is also lacking in most snake life around its shore line and it is completely brackish water but to be very truthful with you I never paid it much attention.  I always figured the high human traffic around the area was a good reason so I left it a that.  This is one of the reasons I love answering questions here, every now and then someone asks a question that I have never ran up against before and I learn something new.
I am going to call the county extension and forest service for New Orleans Parish and put this question to them and see what they think.  If you have time, do the same for your area lake, one of us will get the answer and inform the other.

              Thank you so much.
                   Joel