Swordfish
Average mercury at 0.995 ppm; among the highest commercially sold. FDA advises pregnant women and children to avoid entirely.
Bluefin Tuna
Atlantic populations down ~72% since the 1970s. Southern Bluefin still Endangered. Recovery remains fragile and uneven.
Atlantic Cod
Gulf of Maine and Georges Bank stocks both overfished. Populations at historic lows despite rebuilding plans and strict quotas.
Red Snapper
Mislabeling rates documented as high as 87%. Sushi restaurants in one study served non-snapper species 100% of the time.
Vietnamese Catfish
70–80% of tested samples showed Vibrio bacterial contamination. Also frequently sold under false names on menus.
Farmed Atlantic Salmon
Research found farmed salmon had significantly higher PCB concentrations than wild-caught counterparts across multiple studies.
Vietnamese Catfish: Bacterial Contamination and Seafood Mislabeling in Plain Sight
Vietnamese catfish — scientifically known as pangasius, and sometimes referred to as tra fish — has become a common and inexpensive white fish filler appearing on restaurant menus across the United States and Europe, often under borrowed identities. This species is almost exclusively farmed, typically raised in densely stocked freshwater ponds along the Mekong River delta, where environmental controls are inconsistent and antibiotic use is widespread. Studies have reported that between 70 and 80 percent of pangasius samples tested positive for Vibrio bacterial contamination — the same class of bacteria responsible for the majority of shellfish-associated food poisonings. Raw or undercooked pangasius can therefore pose genuine hazards to consumers who have no idea they are eating it.
Making matters worse is the documented pattern of deceptive labeling. Investigations have confirmed that pangasius is regularly sold at restaurants under the name of more desirable and expensive species — grouper and sole being among the most common substitutions. A 2015 investigation in Atlanta alone found that more than a third of restaurants examined were serving pangasius as grouper. The Monterey Bay Aquarium’s Seafood Watch program, one of the most respected consumer seafood guides in North America, places pangasius in its lowest tier — a formal recommendation to avoid the species. Beyond bacterial risk, the farming method raises significant environmental concerns: waste and contaminated water from pangasius ponds is routinely discharged into the Mekong River and its tributaries, polluting waterways that sustain local ecosystems and communities. Diners who specifically want catfish are better served by requesting domestically farmed catfish from certified U.S. operations, which are subject to more stringent environmental and food safety regulations.
Farmed Atlantic Salmon: PCB Levels and the Case for Wild-Caught Alternatives
Farmed Atlantic salmon is one of the most widely consumed fish in the world, and its ubiquity on restaurant menus contributes to the popular perception that it is uniformly healthy. Research has complicated that picture considerably. A comprehensive analysis of more than two metric tons of salmon samples from North America, South America, and Europe found that farm-raised Atlantic salmon contained significantly elevated levels of multiple toxins compared to their wild-caught counterparts. In studies comparing farmed salmon from Maine and Canada to wild Alaskan Chinook, total PCB concentrations in farmed fish were measurably higher than in wild samples — a pattern that extended to other organochlorine compounds including dioxins and banned agricultural pesticides. One summary of the evidence noted that for virtually every toxin tested across a global sampling effort, farmed salmon recorded higher concentrations than wild-caught fish.
Multiple independent studies have found that farmed Atlantic salmon tends to carry higher PCB burdens than wild Pacific salmon — a difference attributed largely to the high-fat feeds used to accelerate growth in aquaculture environments, which concentrate lipophilic contaminants. Wild salmon also delivers a substantially more favorable omega-3 fatty acid profile, with studies showing that the marine long-chain omega-3 proportion in wild fish can be roughly three times higher than in farmed counterparts. Skin removal from farmed salmon fillets does not reliably reduce contaminant exposure, as contaminant levels in de-skinned samples have at times remained elevated.
It is important to note that the scientific literature is not entirely one-sided: some more recent Norwegian studies of farmed versus wild Atlantic salmon have found lower contaminant levels in some farmed fish, reflecting ongoing industry efforts to reformulate feed. The debate continues in research circles, and contaminant levels can vary significantly by farm region, feed source, and production year. That nuance notwithstanding, the consistent recommendation from nutritionists and food safety researchers is that when salmon is on a restaurant menu, wild-caught Alaskan species — sockeye, coho, or pink — are nutritionally superior choices. They carry meaningfully lower saturated fat content, higher concentrations of beneficial marine omega-3 fatty acids, and, across most published studies, a lower chemical burden.
