Here are a few seahorse locations found on a few of the most recent releases....
HL367
Sankaty Head, MA: Just to Right of Electrical Jack on Cliff (Only head and torso visable)
HL482
Baltimore Harbor, MD: Just Right of Flag in Water
HL724
Perkins Island, ME(2008 Christmas): Left of Electrical Jack between Jack and Bell Tower in Rocks
HL800
Loon Island, NH(2008 Store Event): Adjacent to, and right of, Flag in Cliff above Water (Only head visable)