Species substitution and mislabeling in the swordfish (Xiphias gladius) market in Santiago, Chile: Implications in shark conservation

Food fraud and the conservation and trade of threatened species are topics of high concern. Some shark species are considered in this category by IUCN and CITES, and can enter as mislabeled or substituted in the commercialization chain. In Chile, three shark species are present as by-catch in the swordfish (Xiphias gladius) fisheries; these are sold headless, gutted, and finned, hindering their identification by morphological traits. Locally, the commercial designation for swordfish is Albacora, while the unofficial name, Albacorilla, is used in the shark products trade. Thus, DNA barcoding was used for taxonomic identification to assess food fraud incident (FFI) percentage in the swordfish market in Santiago. Muscle samples (n = 47) sold under Albacora or Albacorilla designations were obtained from supermarkets, fish markets, and open-air markets. We predicted the fraud probability by a fitted logistic regression model. The majority (91.48%) of the samples were identified as swordfish, while 6.39% were identified as porbeagle shark (Lamna nasus) and 2.13% as shortfin mako (Isurus oxyrinchus). These shark species are classified as vulnerable and endangered (IUCN), respectively, and listed in Appendix II (CITES). The FFI was 8.52%, including mislabeling (2.13%) found only in fish markets and substitution which was reported in fish markets (4.26%) and open-air markets (2.13%). No FFI were detected in supermarkets. The sales price was significant to explain FFI in the logistic model. We conclude that it is necessary to increase stakeholder awareness about shark conservation status, developing specific labelling legislation containing the scientific names and commercial designations for each shark species, and carry out effective enforcement programs of the labelling regulations using DNA-based methods.

Automated summary

Research in Chile identified food fraud incidents in the swordfish market, with vulnerable shark species being mislabeled or substituted. It is recommended to raise stakeholder awareness on shark conservation, establish specific labeling regulations, and enforce them effectively with DNA-based methods.