Despite their size, bad reputation, and Hollywood stardom, there’s still a lot we don’t know about great white sharks. That’s especially true regarding their Atlantic Ocean migration. A new study has looked into this mysterious facet of their behavior, only to consolidate their place on the list of the world's most awesome creatures.
It turns out that Atlantic great white sharks swim way farther offshore than we thought, sometimes making 3,701-kilometer (2,300-mile) trips from Cape Code in the US to the Portuguese islands of Azores.
They also frequently dive to insanely deep depths of 1,128 meters (3,700 feet). Only a small amount of sunlight penetrates beyond 200 meters (656 feet), and by 1,000 meters (3,280 feet) there is no light at all in most parts of the world. That means great whites are swimming around in the pitch-black aphotic, or “midnight”, zone of the Atlantic.
However, it is still a mystery as to why they swim such great distances, although it's likely associated with some kind of offshore foraging facilitated by the thermal physiology of the species. The researchers are also looking into how climate change could be affecting the shark's migration routes.
"These sharks moved daily to depths of up to 1,128 meters, spending significant time at specific mesopelagic depth zones through a temperature range of 1.6 to 30.4°C [35 to 87°F]," the study authors write in the journal Marine Ecology Progress Series.
The research was done by scientists from the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, as reported by the Associated Press (AP).
“Everything we knew previously indicated that the white shark in the Atlantic is more coastally-oriented, moving north-to-south and remaining on the continental shelf," Gregory Skomal, the study's lead author, told the AP. "So what we're now describing is this other component, this offshore movement into open ocean."
They came to these findings after tracking 32 sharks with satellite-based tags between 2009 and 2014. They found that these Atlantic sharks follow a north-south migration path along the eastern coast of the Americas, heading up north in the warmer summer months, then down south to South Carolina, Florida, Georgia, and the Bahamas for the winter.