Environmentally friendly sea shell collections available for purchase?

[winstonlove2005]

Hello,  
I am wary of purchasing shells from dealers or gift shops because I have no idea how the vendor has procured the specimens they are selling.  I'm only interested in purchasing sea shells that have been collected using "environmentally friendly" methods. I don't want to support a business/person that is harvesting these beautiful creatures without regard to the impact this activity has on the ocean's ecosystems and on the species themselves.

Is there a list of 'environmentally conscious' vendors available on this website, or on a similar website?  Or, is there a way that vendors denote which specimens were harvested alive vs. found after natural death has occurred?