The efforts of enthusiastic scientists off the coast of Nova Scotia are raising ethical questions over methods used to attract and study great white sharks

Ocearch is best-known in Nova Scotia for tagging Hilton, a celebrity great white shark who regularly reveals his location in a wry and charming Twitter feed that has almost 45,000 followers.

According to new scientific research, the population of the Marko shark — one of the apex predators in the region — is in severe decline in regions of the North Atlantic Ocean.