Tiger Tracks: How the GHOF Maps Tiger Shark Migrations in the Western Atlantic

For the past two years, the Guy Harvey Ocean Foundation and the Guy Harvey Research Institute at Nova Southeastern University have been sponsoring and conducting an ongoing project to tag and track tiger sharks in the western Atlantic. The goal of this long-term study is to gain a better understanding of the migration of the tiger sharks in this region and to use that data to aid conservation efforts.

BERMUDA

The research program initially started in Bermuda in August 2009 in collaboration with Dr. Neil Burnie and Choy Aming of the Bermuda Shark Project and with generous satellite tag donations from Microwave Telemetry Inc. This study then continued with another tagging session in Bermuda this past July. Many of the sharks are regularly reporting in via their satellite tag, including two of the seven sharks from the original tagging session – 18 months ago! Tracking the same two sharks for this length of time is an unprecedented feat, so the team from the GHOF/GHRI is now leading a project that is producing groundbreaking research – very exciting!

Most of the sharks from the second tagging session appear to be following the same general movement patterns as the sharks tagged in 2009, which is a migration south to the warmer Caribbean waters during the winter months. We don’t know yet why they are moving – it could be due to changes in the water temps, or maybe the sharks are following food sources south. Perhaps it’s some combination of the two, or it could be due to reasons we do not yet know…

BAHAMAS

After the successes in Bermuda, the tagging and tracking process has now expanded to the Bahamas in an area known as Tiger Beach. After several trips to scout and document the area’s tiger shark population over the past two years, the GHOF/GHRI in collaboration with Jim Abernethy’s Scuba Adventures began tagging tigers at this location in December 2010. Like Bermuda, the tigers in the Bahamas are regularly “phoning in” their locations.

The satellite tracking shows that most are still in the same general vicinity as when they were tagged in December, and this was witnessed firsthand in mid-January when several members of the expedition returned to Tiger Beach and were able to photograph one of the tagged sharks.

WHAT NEXT?

It will be interesting to see where these sharks go as the waters warm up in the spring and summer. Many of the sharks from the Bermuda populations headed to the warmer Caribbean waters when the western Atlantic cooled off in fall and winter, then returned “home” during the warmer months.

Are the sharks in Tiger Beach temporary residents as well, just wintering in the Bahamas until they return to the upper Atlantic with warming temps, or is this population more or less a permanent fixture at Tiger Beach? Hopefully, our tagged tigers will call us in the coming months and let us know!

Given the exciting and unprecedented findings obtained thus far, the GHOF/GHRI have expanded their tiger shark research to sites in the Cayman Islands, USVI and Western Australia. This work is being done in close collaboration with colleagues from Marine Conservation International, Save Our Seas Foundation, Cayman Islands Department of Environment, the UK Overseas Territories Environment Programme, the University of the Virgin Islands and Florida International University.

The initial results are already hinting at even more novel findings about tiger shark behavior. Stay tuned for updates as the sharks “phone in”.

Expedition Summaries, Photos/Tracking Maps and Updates:

Bermuda – August 2009 Summary

Bermuda – August 2009 Photos/Tracking Maps

Update #1

Update #2

Update #3

Update #4

Bermuda – July 2010 Summary

Bermuda – July 2010 Summary by Jessica Harvey

Bermuda – July 2010 Photos/Tracking Maps

Bahamas – May 2009 Photos

Bahamas – December 2010 Photos/Tracking Map

Cheers!

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