Multiple drivers behind mislabeling of fish from artisanal fisheries in La Paz, Mexico

Abstract

Seafood mislabeling has the potential to mask changes in the supply of species due to overfishing, while also preventing consumers from making informed choices about the origin, quality and sustainability of their food. Thus, there is a need to understand mislabeling and analyze the potential causes behind it to propose solutions. We conducted a COI DNA barcoding study in La Paz, Baja California Sur, Mexico, with 74 samples from fish markets and 50 samples from restaurants. We identified 38 species sold under 19 commercial names, from which at least ∼80% came from local small-scale fisheries. Overall, 49 samples, representing 40% (95% CI [31.4–48.3]) were considered mislabeled in our samples. Based on analyses where species were assigned to three price categories, economic incentives were associated with approximately half of the mislabeling events observed, suggesting that other motivating factors might simultaneously be at play. Using a network approach to describe both mislabeling (when species are mislabeled as the focal species) and substitution (when the focal species is used as substitute for others), we calculated proxies for the net availability of each species in the market. We found that local fish landings were a significant predictor of the net availability of the 10 most important commercial species at retail, but this true availability was masked to the eyes of the final consumer by both mislabeling and substitution. We hypothesize that the level of supply of each species could help explain mislabeling and substitution rates, where species in low supply and high demand could show higher mislabeling rates and rarely be used as substitutes, while species in high supply and low demand could be used as substitutes for the preferred species. Other factors affecting mislabeling include national regulations that restrict the fishing or commercialization of certain species and local and global campaigns that discourage specific patterns of consumption. We discuss how these factors might influence mislabeling and propose some solutions related to communication and education efforts to this local and global challenge.

DNA barcoding reveals global and local influences on patterns of mislabeling and substitution in the trade of fish in Mexico

“…We followed a recently developed framework based on network analysis to describe how a particular species is mislabeled and used as a substitute to other species to estimate its net availability in our sampling (See Table 1 for detailed definitions of each term) [ 20 ]. We defined focal species as a particular commercial name for which mislabeling or substitution is being estimated.…”

“…This effect referred to as “dilution”, occurs when declines in supply from individual fisheries are hidden from consumers through substitution with alternative species, including those from aquaculture [ 19 ]. Understanding the dilution effect requires the classical approach of explaining which species are mislabeled while looking at the complementary question of which species are used as substitutes [ 20 ]. Under this rationale, mislabeling could be explained as a balance between supply and demand of species in the market, where species with high demand and low supply can be expected to show higher levels of mislabeling and rarely be used as substitutes.…”

“…A study from fish markets in Mexico City, Gulf and Caribbean coasts of Mexico found 18% mislabeling and the commercialization of threatened species of bony fish and sharks according to the IUCN Red List criteria [ 37 ]. A recent study focused on small-scale fisheries reported 40% mislabeling in fish markets and restaurants from La Paz, Mexico [ 20 ].…”

Fish provision in a changing environment: The buffering effect of regional trade networks

“…Such examples of non-substitutability between fish species are common in fisheries [ 41 ]. For instance, in our case study, triggerfish (sold as processed fish in the regional market) and red snapper (sold as an entire fish to international and other high-value markets) are rarely substituted [ 42 ].…”

Falsificações por troca de espécies de peixes: uma revisão sistemática das espécies mais comumente substituídas

“…No que tange à prevalência das espécies em casos de falsificação, há algumas espécies mais propensas a serem rotuladas incorretamente do que outras 6,7 . Além disso, tal rotulagem errônea pode ocorrer de forma intencional ou não, ao longo de toda a cadeia de abastecimento 7,8 .…”