Great whites store up fat for travel

PACIFIC GROVE (USA)- Researchers at the Hopkins Marine Station in Pacific Grove said they have discovered that great white sharks store oil in their liver and then deplete it as they travel monumental distances.

Where the sharks go is pretty well documented thanks to all the tagging programs. But how and why they travel is still not certain.

Researcher Gen Del Raye of the Hopkins Marine Station came up with the idea to test how the density of fat stored in the great white shark’s massive liver affected its buoyancy.

Great white sharks use a swim-glide pattern. They swim and then let themselves slide throught the water. A shark with more fat sinks more gradually, Del Raye found out.

He did part of his research at the Monterey Bay Aquarium where a captive juvenile great white was held.. With the aid of aquarium research scientist Sal Jorgensen, Del Raye observed and recorded how its swim-glide pattern was affected by the luxury diet provided by the aquarium’s husbandry staff.

After observing the captive shark, Del Raye compared his observations with Hopkins’ data on tagged great whites migrating in the Pacific Ocean.

By comparing these data sets using mathematical analyses, Del Raye discovered that migrating great white sharks sank at quicker rates as they migrated, suggesting they were using the fats in their liver to fuel their long journey.

Read more at Monterey Herald

http://www.montereyherald.com/ci_23675030/hopkins-marine-station-study-sheds-light-shark-migrations