Sharks are evolutionary survivors that have existed for more than 400 million years.
Sharks have been fished commercially in the USA waters only since the 1970s. That caused stocks to plummet by as much as 80 percent for some Atlantic species. In 1997, 22 species of coastal sharks were classified as overfished or fully fished, meaning no additional increases in fishing could be tolerated without endangering the health of the population.
In Costa Rica, a company that marketed crushed shark cartilage to western pharmaceutical firms as a cancer remedy saw its monthly production soar from 1,400 to 10,000 kilograms in 1997.