More than six out of every ten fish purchases in Los Cabos turn out to be a different species than what the label or menu claims. That is the finding of a new report by Oceana, the global ocean conservation group, which tested 1,262 seafood samples across Mexico’s ten largest cities and found a national fraud rate of 38%. Los Cabos topped the chart at over 60%, making it the worst city in the study for fish fraud, and nearly triple the roughly 20% global average cited by the United Nations Food and Agriculture Organization (FAO).
Los Cabos Fish Fraud Rate Is Triple the Global Average
The Oceana report, titled Gato X Liebre: engaño vigente, solución pendiente (a play on the Spanish idiom gato por liebre, meaning to pass off something inferior as something better), sampled restaurants and markets in cities including Culiacán (53% substitution), Mazatlán (36%), and Los Cabos (over 60%). Researchers used DNA testing to verify whether the species on the label matched the species on the plate.
The results for specific fish types are striking. Every single sample sold as sailfish (pez vela) turned out to be a different species, a 100% substitution rate. Marlin (marlín) came in at 91% substitution. Sea bass (lobina) was mislabeled 89% of the time. And red snapper (huachinango), one of the most popular fish on Los Cabos menus, was substituted in 54% of cases.
The replacements were often far cheaper species. Restaurants and vendors sold tilapia or catfish (bagre) in place of red snapper, grouper (mero), and marlin. In some cases, red snapper was swapped with up to 16 different species. Marlin, a trophy fish that draws thousands of sport anglers to Los Cabos each fall during tournament season, was replaced in certain samples with shark species listed as at risk.
That last detail carries ecological weight. Los Cabos sits at the southern tip of the Baja California peninsula, where the Sea of Cortez meets the Pacific Ocean. The region’s marine biodiversity is one of its primary draws. Jacques Cousteau famously called the Sea of Cortez “the world’s aquarium.” Selling at-risk shark meat under a marlin label means consumers unknowingly fuel demand for threatened species while believing they are eating something abundant.
No Traceability System Exists From Boat to Plate
Mexico currently lacks a national seafood traceability standard. Once a fish leaves the boat, no mandatory system tracks it through processing, distribution, and final sale. “There are no measures that give us complete information about the journey of fish products from boat to plate,” said Esteban García-Peña, coordinator of Research and Public Policy at Oceana.
This gap means that even well-intentioned restaurants may not know what they are serving. Fish can change hands several times between the dock and the kitchen, and each handoff introduces an opportunity for relabeling. The problem is not unique to Mexico. A 2021 Oceana study found 26% mislabeling in restaurants across the United States. But Mexico’s 38% national rate, and Los Cabos’s 60%-plus rate, sit well above that benchmark.
The irony is hard to miss. Los Cabos hosts major international sport fishing tournaments, including the Bisbee’s Black and Blue, which awarded over $5.5 million in prize money in its 2024 edition. The city markets itself as a world-class fishing destination. Yet its restaurants and fish markets are, by this measure, the least reliable places in Mexico to get the species you pay for.
Practical Steps for Buying Fish in Los Cabos
Oceana’s central recommendation is systemic: Mexico needs a traceability standard that follows each product from catch to consumer. That kind of regulation takes years. In the meantime, buyers in Los Cabos can take a few steps to reduce the odds of getting swindled.
Whole fish is harder to fake than fillets. A whole red snapper has distinctive features (reddish skin, a specific head shape) that are easy to verify. A fillet on a plate is just white or pink protein. Buying from fishermen directly at the dock, or from established pescaderías (fish shops) with visible supply chains, improves your odds. Some restaurants in Cabo San Lucas and San José del Cabo now list the boat or cooperative that supplies their catch. That transparency is a good sign, even without a formal certification program.
Be skeptical of menu items priced suspiciously low. If a marlin entrée costs 180 pesos (about $10 USD), it is likely not marlin. Grouper, red snapper, and marlin command premium prices because they are premium fish. A bargain may mean you are eating tilapia at grouper markup, or catfish dressed up as snapper.
Oceana is pushing for legislation that would require Mexican seafood sellers to document the species, catch method, and origin of their products. No timeline for such a law has been announced. The full Oceana report, published in Spanish, is available through the Zenodo open-access research repository. Reporting on the study was published by López Dóriga Digital, El Debate, and El Heraldo de San Luis Potosí.