What exactly is the fish in a Filet-O-Fish sandwich? It’s a bug-eyed creature from New Zealand called the hoki, and it is apparently under pressure from overfishing, the New York Times reports. New Zealand—while not specifically citing that cause—has been cutting the allowable catch as conservation groups express concerns about sustainability. McDonald's alone uses 11 million pounds a year, down from 15 million, and chains such as Denny's and Long John Silver's also like it.
New Zealand once allowed fishermen to bring in 275,000 tons of hoki yearly, under the belief that the fish’s relatively quick life cycle (25 years) made that workable. The ceiling has since been lowered to 100,000 tons as hoki numbers have fallen. The fishery has been certified as sustainable by a group in London whose seal of approval is sought by restaurants, but environmental groups such as the World Wildwife Fund have "major concerns," says a spokesman.