Conservation groups said 80 species were known to have gone extinct, 16 in the last year alone. Millions of people rely on freshwater fish for food and as a source of income through angling and the pet trade. But numbers have plummeted due to pressures including pollution, unsustainable fishing, and the damming and draining of rivers and wetlands. The report said populations of migratory fish have fallen by three-quarters in the last 50 years. Over the same time period, populations of larger species, known as “megafish”, have crashed by 94%.