Seven categories. One shared language for seafood fraud.

Illegal, Unreported and Unregulated (IUU) fishing accounts for a significant share of global seafood volume. The fraud isn't just the catch itself — it's the laundering pathway that transforms IUU product into apparently-legal commerce. Vessels transhipment at sea, paperwork is rewritten in flag-of-convenience ports, and the catch enters processing facilities indistinguishable from licit product.

Why it persists: the price differential between legal and IUU product covers the cost of laundering many times over, and prosecutions are rare even where laws exist.

Counterfeit fraud creates the appearance of certification or premium origin where none exists. This includes forged sustainability certifications, fabricated geographic-indication labels, and manufactured "boutique" brands that have no link to any real harvest, vessel, or producer.

Why it persists: certification marks add real price premiums, and verification at the point of sale is rare. A consumer almost never verifies a label against a certifier's database.

Adulteration adds substances to seafood that weren't disclosed on the label. This includes water-binding phosphates that increase pack weight by 20–30%, sulphites that prevent black-spot in prawns but trigger allergic reactions in sensitive consumers, and a range of undisclosed brines and preservatives.

Why it persists: labelling laws often allow "moisture added" or carrier statements without quantification, and consumer testing of specific additives is functionally impossible at the counter.

Dilution makes the pack appear larger or more premium than it is. Frozen prawn glazing — a thin protective ice coating — can legitimately be 5–10% by weight; industry surveys regularly find 30–40%. Species mixing blends cheaper fish into a premium-labelled product so the average species composition still matches the label, but the consumer paid premium prices for filler.

Why it persists: "net weight after deglazing" is rarely declared, and species mixing requires DNA testing to detect.

Misrepresentation falsifies country-of-origin, harvest method, or sustainability claims while leaving the species itself accurate. This is the fraud behind "Australian prawns" that were processed in Australia but caught elsewhere, "wild-caught" salmon that was farmed, and "sustainable" claims unsupported by any actual certification.

Why it persists: origin labelling rules vary across jurisdictions, and "processed in" loopholes let importers technically meet the letter of the law while violating its intent.

Unreported product moves through informal supply chains that bypass standard traceability. This isn't necessarily illegal at the point of catch — but at some point the documentation breaks, the species is recombined with traceable product, and the original chain of custody is lost. The practical result: nobody can answer where this fish came from.

Why it persists: small-volume informal trade fills genuine gaps in regulated supply, and enforcement against grey channels is resource-intensive relative to the per-incident value.