A study tracking the migratory patterns of tiger sharks across the Southwest Pacific reveals that coastal marine parks provide only brief protection for these important marine predators, while oceanic reefs, vital to their ecology, are overlooked.
Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions.
A four-year study by shark research scientist, Dr Jonathan Werry, in collaboration with the French government, followed the movement of tiger sharks across the Coral Sea. The study looked at migratory movements and fidelity to specific reefs for tiger sharks tagged in New Caledonia, the east coast of Australia (the Great Barrier Reef) and oceanic reefs in the centre of the Coral Sea. Thirty-three tiger sharks (1.54 to 3.9m in total length) were tagged with passive acoustic transmitters and their localized movements monitored on receiver arrays.
Understanding the habitat-use and migration patterns of large sharks is extremely important for assessing the effectiveness of Marine Protected Areas.
From 2009 to 2013, 14 sharks with satellite and acoustic tags undertook wide-ranging movements up to 1,114km across the Coral Sea. One 3.7m female tiger shark was recorded to a previously unknown depth of 1,136m. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks.
Tiger sharks are often considered to be a reef-associated "coastal" species that exhibits seasonal and diel visits to coral reef lagoons when traversing between coral shoals and atolls. On coastal reefs, however, all of the monitored tiger sharks were found to be transient.