Shark Deception: Molecular Tech Uncovers Widespread Mislabeling of Shark Meat as Corvina in Ecuador

A recent study utilizing advanced molecular technology has revealed a disturbing trend in Ecuador: shark meat is frequently being sold to consumers under the guise of corvina. This practice not only deceives the public but also raises significant concerns for the conservation of vulnerable shark species, some of which are protected.

Key Takeaways

• Nearly half of fish samples labeled as corvina in Ecuadorian markets were found to be shark meat.
• Vulnerable and protected shark species, including the silky shark and smooth hammerhead, were identified among the mislabeled samples.
• Molecular techniques like PCR offer an accessible and effective method for species identification and market regulation.
• The study highlights potential loopholes in regulations regarding incidentally caught sharks, which may facilitate the sale of protected species.

The Shocking Discovery

Researchers revisited a study from ten years prior that first identified mislabeled fish in Ecuadorian markets. The initial investigation found that over 26% of samples sold as corvina were actually shark meat. Suspecting the problem persisted, a new study was conducted in 2023. The results were alarming: almost 47.42% of the fish fillets purchased and labeled as corvina in markets across Quito, Cuenca, Ibarra, Ambato, Manta, and Guayaquil turned out to be shark meat.

The positive identifications were concentrated in the Andean cities of Quito, Cuenca, and Ibarra, where consumers may have less familiarity with distinguishing fish species due to lower fish consumption rates.

Molecular Technology: A Powerful Tool

The study employed Polymerase Chain Reaction (PCR) techniques, a method familiar to many from its use during the COVID-19 pandemic. This technology allows scientists to amplify small fragments of DNA, making it possible to identify species even from tiny tissue samples, especially when visual identification is difficult. Researchers first used a PCR test to confirm if the meat was from a shark. If positive, a second test identified the specific shark species with a reported 97.8% accuracy.

Vulnerable Species at Risk

Among the shark species identified were the silky shark (Carcharhinus falciformis) and the smooth hammerhead shark (Sphyrna zygaena), both listed as vulnerable on the IUCN Red List. The pelagic thresher shark (Alopias pelagicus) and the blue shark (Prionace glauca) were also detected. The smooth hammerhead shark is fully protected in Ecuador, meaning its capture and sale are prohibited, even if caught incidentally.

Regulatory Concerns and Consumer Rights

Ecuadorian regulations permit the sale of sharks caught "incidentally" – meaning unintentionally during fishing for other species. However, the study’s authors suggest this provision could inadvertently lead to the sale of over two million sharks annually and increase the risk of protected species entering the market. "Although regulations exist, the capture of fully protected species is evident," noted researcher Gabriela Pozo. She emphasized the need for greater regulation and public discussion surrounding the sale of incidentally caught sharks.

Scientists stressed the importance of traceability and consumer awareness. Juan José Guadalupe, a researcher involved in the study, stated, "Simple tools like PCR allow us to perform this type of analysis… and this is key to regulating the market and contributing to the conservation of vulnerable species."

Moving Forward

The researchers recommend expanding these analyses to more cities and conducting them at different times to better understand the scope and persistence of the mislabeling trend. They also advocate for the public sector to adopt these accessible molecular methods to ensure consumers know what they are purchasing and to bolster conservation efforts for marine species facing significant pressure.

Sources

• Molecular technology reveals that shark meat is being sold as corvina in Ecuador | Science, EL PAÍS English.