[BrownstoneNorth]

Originally Posted by Outdoorsman

Duck itch is not exclusive to any body of water and it is not specific years that it happens.... it just does

As to your request for "proof"
3 beaches in laconia
http://www.wmur.com/news/nh-news/3-l...teria/21178832

Too many to mention in various towns last year
http://www.wmur.com/escape-outside/b...indge/35086910

8 more public beaches closed last year
http://www.wmur.com/escape-outside/s...aches/34333244

There must be another reason for the bedbugs

The beach advisories you cited are for E-coli and Cyanobacteria and very different from swimmers itch/duck itch, which, though extremely obnoxious, are not considered "health hazards" by the DES. The OP is correct that NH beaches are neither signed with warnings nor closed for evidence of swimmers itch/duck itch.

http://www.nhstateparks.com/swimmersitch.html

As an example, Wolfeboro's Carrie Beach has one of the cleanest DES records but is notorious among people in the know for swimmers itch/duck itch.