A bluefin tuna weighing 222 kilograms sold for ¥155 million (US$1.7 million) in Tokyo last month. This is an all-time record price for a single fish, driven skywards by increasing demand and dwindling supply.

Populations of bluefin tuna (Thunnus spp.) are a fraction of what they were 50 years ago (see, for example, go.nature.com/5advqj), in large part because of the increasing value of the high-end sushi and sashimi market. Individuals are caught long before they reach full size (around 650 kg).

Conservation is being delayed as economic and political interests override biological concerns. The Convention on International Trade in Endangered Species of Wild Flora and Fauna helps to protect imperilled species, but has evaluated barely 3% of described species since it came into force in 1975. Similarly, the International Union for Conservation of Nature (IUCN) lists fewer than 100 fish species out of a total of 25,000 in any of the categories of its Red List of threatened species.

Even when complete information is available for heavily affected marine species (giant flatfish and billfish, for example), the IUCN's worldwide voting procedures impose delays on ranking in the list.