Other species such as blacktip reef sharks did not show this behaviour.

BBC: Sharks navigate using 'mental maps'

They also provide a habitat for fish and other species of ecological and commercial interest, such as orange roughy, swordfish, tuna, sharks, turtles and whales.

UNESCO: MEDIA SERVICES

In sharks with a usual head, such as the lemon shark (Negaprion brevirostris), the field of vision of each eye overlaps by just 10 degrees.

BBC: Earth News - Hammerhead shark mystery solved

Sharks regularly become impaled on hooks dragged by boats targeting high-value species such as tuna, or entangled in nets.

BBC: EU gives shark protection teeth

"Young people want to conserve sharks but their families feel that shark's fin must be served at important events such as wedding banquets, " says the executive director, Simon Wong.

BBC: Hong Kong shark fin trade declines