Elasmobranchs first evolved over 400 million years ago. They are superbly adapted to their environment, showing remarkable diversity and variation in their physical appearance, their biology, and their behaviour. They inhabit every ocean on the planet and yet, they are under ever-increasing pressures which challenge their ability to survive.
Commercial over-fishing is by the far the greatest threat to elasmobranchs. They are targeted for their meat, fins and liver oil. Additional pressures such as the destruction and pollution of their habitat, the demand for shark cartilage (although usually taken from sharks already killed by fisheries), poor angling practices, ocean acidification and climate change as well as poorly managed wildlife tourism are all factors contributing to the decline of shark populations worldwide. Collectively these threats result in an estimated figure of between 63 and 273 million sharks being killed every year by humans.
As most elasmobranch species grow slowly, mature late and give birth to relatively few pups, they simply cannot sustain these pressures, thus many species have been severely depleted, with population numbers recovering very slowly if at all. The need for effective management practices and crucially the enforcement of these, are essential to safeguard sharks.