need help in understanding NOC & its prerequisites

[Canadaluck]

Hello Experts !

Please help me understand how to confirm the correct NOC relevant to my qualification and experience. I hold a doctorate degree(PHD) in chemistry and have 6 years of oil field experience in R & D area.

I tried below link and found it matches to 2112 Chemists , and have chemistry research scientist in the list

http://noc.esdc.gc.ca/English/NOC/SearchNocCodeResult.aspx?val17=2112&val18=0&val19=0

infact when I search the details under Employment requirements it says :

Licensing by a provincial association of chemists is required in Quebec, and available but voluntary in Nova Scotia, Ontario, Alberta and British Columbia.

please explain what does it mean ?

Thanks