A difficulty in obtaining information about wild animal behaviour is that detailed observations of different individuals is necessary over long periods of time, and this is especially hard to achieve with sharks. But in the shallow lagoons of French Polynesia, such observation was possible without the encumbrance of scuba gear, and without the problem of the shark disappearing into the depths.
The primary method of age estimation in fishes relies on counting growth increments in mineralized tissues, including otoliths, vertebrae, and fin rays.
Previously, researchers assumed that each stripe corresponded to annual growth, which isn't necessarily true throughout a shark's life. And because these bands can vary in width and colouration, it can be difficult to distinguish them.
The team analyzed the radiocarbon from the vertebrae of four female and four male great white sharks that were captured in the Atlantic Ocean from 1967 to 2010.
"We found that newborn sharks captured in the mid-1990s left the safety of the islands when they were between five and eight years old," explained Dr Kevin Feldheim, the A. Watson Armour III Manager of the Pritzker Laboratory for Molecular Systematics and Evolution at The Field Museum and the lead author of the study.
Jim Abernethy, owner and operator of Scuba Adventures, was the dive operator who showed all of the others that sharks are peaceful animals who want nothing to do with humans as a food source.
He spends most of his time with wild sharks during dives from his liveaboard ship, The Shear Water, at remote sites in the vicinity of the Bahamas, and is on land for only about 40 days a year.
Shark finning refers to the removal and retention of shark fins while the remainder of the living shark is discarded in the ocean.
NBA All-Star Yao Ming pledged to stop eating shark fin soup at a news conference on August 2, 2006. However at that time Yao's comments were largely unreported in the Chinese media.
Underwater photographer Peter Verhoog of the Dutch Shark Society is on a mission—a mission to save sharks. He wants to raise awareness for sharks and their fate among a wide audience. One of the ways to do this is to show people not only the beauty of sharks but also shark behaviour and their sometimes worldwide migration and feeding patterns.