Dunedin Causeway Etiquette

I'd like to make a suggestion to bikers on our beautiful stretch of the trail leading to Honeymoon Island.  Until the time comes when a seperate lane is established for bikers and walkers/runners, please please alert walkers when you are about to pass them.  As a frequent walker on the causeway, I am always appreciative of a bell or verbal alert that you are about to pass.  However, many times bikers aproach quickly from behind with no notice.  I've witnessed many near misses between bikes and pedestrians.  Thank You!