You did not specify which school.
when used without any further specification is taken to mean the Berkeley campus.
The first three I checked do all offer scuba certification. Those certifications were through PADI, NAUI, and SSI (in the order I checked them).
I assume you searched for: "University of California diving certification." When I search for "University of California diving certification", the first hit is for:
UC Berkeley - Scientific Diving Program, a site that says, somewhat confusingly, "The Diving Safety Program provides opportunities for students, faculty, and staff to pursue SCUBA certification or a scientific diver permit."
More typical of the programs is a statement like this one on the UCLA course description: "The course is based on the American Academy of Underwater Sciences (AAUS) Standards in order to dive under the auspices of UCLA or any other AAUS Organizational Members like the California Science Center, Scripps Institute of Oceanography, UCSB, etc.
In order to be fully certified as an AAUS/UCLA scientific diver, already certified divers must complete a check-out open water scuba dive with the DSO and at least 11 additional dives under the direction of the DSO or a delegate for a total of at least 12 open water dives. Depending on the individual diver's ability, additional dives might be required for those divers. Divers must demonstrate adequate scuba skills, knowledge of the local diving environment, successfully complete ALL pool work, lectures, and pass a written final exam. See below list of requirements for specific details.
Upon successful completion of the course and an additional 50 logged dives, divers will be eligible for a NAUI Master Diver Certification, NAUI's highest non-instructional certification." (bolding added).
About the same thing is true in all the U.C. programs that I've worked with:
Berkeley,
Davis,
Scripps,
Santa Barbara,
Santa Cruz, and
Los Angeles. I still often get tanks filled and get on dive boats with my Berkeley Card, circa 1973, that has no mention of any recreational agency on it, yet has been accepted everywhere I've traveled.