They are found throughout the world's oceans, although one species, the bull shark, can live in fresh water. The largest species, basking and whale sharks, feed by filtering plankton out of the water, while the majority of sharks are predators feeding on the top of the food chain.
Most sharks are long-lived, grow slowly, mature late and produce few offspring.
Consequently, they are particularly susceptible to overfishing, and very slow to recover once depleted. Large coastal sharks have been popular sport fish since the 1970s, but most of the decline in their population took place in the 1980s, when a commercial fishery developed in response to the Asian market for shark fin soup. Atlantic pelagic sharks, such as mako sharks, are probably depleted also, but there is very little information on their status. In the Pacific, the status of sharks is unknown, although there are several fisheries. On both coasts, there is a need for better data and better management in order to stop the depletion of sharks and help depleted populations to rebuild.