Years of study tracking sharks in the Atlantic Ocean may have revealed a warm-weather aggregation point for great white sharks, according to OCEARCH. Researchers have dubbed this region as the Northwest Atlantic Shared Foraging Area (NASFA).
Satellite tracking data from the OCEARCH Tracker database system revealed, since 2012, the Atlantic continental shelf waters off North Carolina, South Carolina, Georgia, and the east coast of Florida are a winter hot spot for large white sharks. Just this year, eight sharks that have been affixed with a satellite tracking device during OCEARCH research missions have “pinged” in in this area, the waters off Charleston, South Carolina, and Cape Canaveral, Florida having the highest concentration of detections.
Nearly all sharks tagged during OCEARCH expeditions — from Nova Scotia, Canada to the Florida Keys — have made there way to the NASFA at some point during their migrations, with most visiting in the winter.
“The body of colder water trapped between the Gulf Stream and the coast is a key feature of this region,” says Assistant Professor of Marine Science at Jacksonville University and OCEARCH collaborating scientist Dr. Bryan Franks. “This ‘wedge’ of cold water extends from the Outer Banks in North Carolina down to Cape Canaveral in Florida. This feature results in a range of water temperatures in a relatively short horizontal distance from the coast out to the Gulf Stream.
“In addition, there is the potential for abundant prey in the migrating populations along the coastlines and in the dynamic mixing zone on the Stream edge.”
A Familiar Phenomena
A similar aggregation of white sharks has been observed in the Pacific Ocean where different shark populations migrate from the Farallon Islands and Guadalupe Island to a Shared Foraging Area (SOFA).
In October, a team of researchers were able to take a closer look by using satellite tags and deep-water remote operated vehicles at what has been dubbed as a “White Shark Cafe” in open water between California and Hawaii. The month-long expedition, which was a joint effort by scientists from Stanford University’s Hopkins Marine Station, the Monterey Bay Aquarium Research Institute, and the Schmidt Ocean Institute, used a multitude of research methods to better understand a mysterious gathering point in the middle of otherwise barren ocean.
OCEARCH previously tracked this behavior in 2007-2009 and conducted a 30-day expedition to the SOFA in 2009.
Continued Research
OCEARCH will launch another expedition to the NASFA in February with two other expeditions planned for Massachusetts and Nova Scotia later in 2019. These expeditions aim to increase the sample size of tagged white sharks to get a clearer picture of white shark movements in the Northwest Atlantic and test scientific hypotheses about white shark movement and migration.
“This is the beauty of OCEARCH’s North Atlantic White Shark Study,” said Dr. Bob Hueter, OCEARCH Chief Science Advisor. “The sharks lead us from one step to the next so that we can steer our ship to where we’re needed to fill in the gaps in our knowledge of this incredible predator. Each expedition builds on the previous ones to reveal the life of the white shark from birth to death in the North Atlantic. This is the best kind of science, and it’s exciting to be sharing these discoveries with our peers and the public.”
You can follow the OCEARCH tagged sharks, including those in the Atlantic, by accessing the near-real time, free online Global Shark Tracker, or by downloading the Global Shark Tracker App available for Apple and Android platforms. You can also follow all the latest OCEARCH-related news from Sharkophile here.
https://www.sharkophile.com/2018/11/27/great-white-katharine-returns-to-florida-waters/