Sunday, April 27, 2014

Where do "our" great white sharks give birth to their young?

Back in 2000, when we started diving with great white sharks at Isla Guadalupe, we knew very little about where the sharks were going, when they are not at the Island. I remember the days, when the scientists thought that they went to Shark cafe/Sofa to mate. Thanks to satellite tagging by Dr. Domeier and his team at MCSI, we now know that males and females are not in the same place, same time in that area. Based on tracking data and the white sharks gestation period of 14-18 months, we now think that they are actually mating at Guadalupe Island.
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific. - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific. - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Domeier M. L. and N. Nasby-Lucas. 2012. Sex specific migration patterns and sexual segregation for adult white sharks in the northeastern Pacific. - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf


The next question of was, where do they give birth? Again, thanks to the long term SPOT tags, (we just talked about the improvements to those tags here) we now have a better idea of where that is taking place. For the females that aggregate at Guadalupe Island, it seems to be off the coast of Baja California MX as well as the Sea of Cortez. (Two-year migration of adult female white sharks (Carcharodon carcharias) reveals widely separated nursery areas and conservation concerns)
Two-year migration of adult female white sharks (Carcharodon carcharias) reveals widely separated nursery areas and conservation concerns - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf
Two-year migration of adult female white sharks (Carcharodon carcharias) reveals widely separated nursery areas and conservation concerns - See more at: http://www.marinecsi.org/publications/#sthash.pCmg6BvH.dpuf

Gill Raker's latest location.
For all of us that don't want to read scientific papers, but still want to know what our sharks are up to, MCSI has this nifty little app. here.

This is the latest post on the MCSI facebook page today, showing what Gill Rakers is up to!

"We have been waiting nearly 17 months to see where Gill Rakers will give birth. Now that we think she is heading for the Sea of Cortez, we must prepare for a stressful 4-6 weeks. The Sea of Cortez is a narrow body of water with intense commercial shark fishing. She will be running the gauntlet, through longlines and gill nets...gear that kills. Our biggest question: Will She Survive?? Watch with us on the Expedition White Shark App...and stay tuned to our FB page."

We all share their concern for Gill Rakers safety. The Sea of Cortez is not a safe place to be, for a great white shark. We hope that we'll see and get to dive with her once again this fall, at Isla Guadalupe.

Cheers,
Martin Graf
CEO Shark Diver 

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com
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