as a pharmacist (NOC 3131):
if you need a license to practice (for example, providing patient care in a community pharmacy, hospital pharmacy, long term care facility or other practice settings) the Pharmacy Examining Board of Canada (PEBC) must do your ECA,
if you are in a position where you do not need a license (organizations such as the pharmaceutical industry and government which require a pharmacy degree because of the education or skill set, but may not require a licence to practice pharmacy), you can have your credentials assessed by one of the other designated ECA organizations. Contact the regulatory authority in the province where you plan to live to find out if you need a licence to practice your intended occupation.
I assume your experience falls into later category with no licence required so WES is fine.