Apple doesn't support Blu-ray
and (from hardmac.com):
"Steve did not change his mind and still think that BD DRM are just inacceptable for mass and consumer market due to restrictions that make advantages look like non competitive. He admitted that retrospectively he feels ashamed that Apple’s name is associated to Blu-ray, as he thinks that BD supporting associations look today more like M*fia than anything else. Concerning authoring on Blu-ray, it seems impossible to provide software supporting such format for consumer market. In addition to DRM, here it is the cost of licenses that slow down the entire process; one would have to start paying 3,000 USD to AACS, then 80,000 USD to Sony, 40,000 USD to Sonic, etc. HE considers the Blu-ray as a “bag of hurt”."
(* = a The full M word is rejected.)
but there is player software
MCE includes a trial version of Blu-ray player software with their drive. (It's out of date but will update to the current version.)
It works fine on my Mac Pro. Enable Deinterlacing and set it to Auto in its Video preference.