how to calculate the distance between multiple points along the coastline?

Discussion created by 122032948 on Jan 5, 2013
Dear all,
I have a multiple records (over 100) of marine organism along or near the coastline. Now I am trying to calculated the pariwise distance between them along the coastline. How can I do that? Any suggestion will be appreciated. thx a lot!!

I attachment a sample file. the red line is the distance I would like to calculate.
thx again!