This sign is at the Herdsman Drain into the ocean at path 12/13, Floreat beach (there may be others). Young freshwater turtles are sometimes washed down the drain, which is an overflow from Herdsman Lake. Marine turtles get swept south in the Leeuwin current. Both types will not survive on their own locally, and need veterinary care. The sign says to wrap them in a towel and to ring 0414 476 867 to arrange for this.