Cathay Pacific consulted the Marine Stewardship Council (MSC) - which certifies sustainable fisheries - early on as part of its plan to establish guidelines for sustainable fisheries.
The council certifies only two fisheries producing shark fin as sustainable: spiny dog fisheries in the US Atlantic and British Columbia. "The fins are by-products and can be used to prepare shark fin soup," spokeswoman Agnes Heng said.
However, she added: "They are not as popular because the fins are a lot smaller."
Cathay's decision not to simply align its policy with MSC guidelines - which some green groups consider not strict enough - has exasperated some environmentalists.
Kari Thomas, a New Zealand-based oceans campaigner for Greenpeace, said: "What the heck can Cathay mean by sustainable shark fin fisheries if the MSC has ruled it out?"
For its definitions of sustainable and traceable, Cathay Pacific is relying on the voluntary work of three marine experts.
Asked how credible the Cathay definitions would be compared to those of organisations like the MSC, expert Nick Dulvy said: "If you are asking if we are going to create another MSC, the short answer is no … All we can do is come up with some practical and defensible principles as to how we view sustainability and how we view traceability."