Even with tougher fishing quotas it will take years to restore shark stocks. One reason is the lack of an international treaty on shark fishing, similar to the global accords that limit commercial catches of blue-fin tuna. Another factor is biological. Sharks are slow to reproduce, having long gestation periods and small litters.
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.