By Mexican law, each restaurant has to have documents proving the legality of their fish. In case of marlin, dorado, sailfish and rooster fish, these are all fish that cannot be traded, unless the restaurant has a proof that the fish has been legally caught by an angler. If the restaurants have such fish stored in their freezers without proof to verify that it is legal, they can be fined.
Many restaurants in Los Cabos provide a “You hook it, we cook” service. In case of the above mentioned fish you don’t need a licence in case the restaurant will prepare the fish at the moment you bring it to them. But if the customer brings his fish in the morning to come to have a dinner from it in the evening, they do need to provide a copy of their license to support the restaurant, in case the authorities come to do an inspection, so they can see that fish is caught legally by a client. Please note that if the fish is caught from the shore, you do not require a fishing license, and you won’t be asked to show the license when you bring it to the restaurant.