Far Fewer Great Whites than Scientists Expected
Researcher:
Taylor Chapple.
Post-doctoral Researcher
Max Planck Institute
E.: tkchapple@ucdavis.edu
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Revised:
April 1, 2011
A researcher takes photos of the dorsal fin of a great white shark. Photo: Stanford University
April 1, 2011
Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334
Far fewer great white sharks are cruising the waters of the northeast Pacific Ocean than previously thought, according to NOAA-funded researchers who conducted a first of a kind census of the iconic predators.
“The low number was a real surprise,” said Taylor Chapple, who was a NOAA Fisheries-Sea Grant Fellow in Population Dynamics and graduate student at UC Davis at the time of the study. “It was lower than we expected, and also substantially smaller than populations of other large marine predators, such as killer whales and polar bears.”
White sharks in the northeast Pacific are one of three known white shark populations in the world. The others are in Australia/New Zealand and South Africa.
Figures a and b show the fin of the same shark in 2007 and 2008; Figure c shows a different shark in 2008, illustrating how distinctive the fin shape can be. PHOTO: Global Tagging of Pelagic Predators
Tagging studies have shown that more than half of the northeast Pacific population aggregates in the same regions off Central California year after year.
Using photographs of individual sharks and statistical methods, the scientists estimated that there are 219 adult and near-adult white sharks in the region off Central California.
The estimate represents a baseline for gauging whether shark populations are viable or critically in danger of collapse or something in between, said Chapple who is now a post-doctoral researcher at the Max Planck Institute in Germany.
The study was published in the March 9 online issue of the journal Biology Letters.
To learn more about how the shark population was estimated, visit:http://www.csgc.ucsd.edu/BOOKSTORE/Resources/PP2011/C-P-1-Chapple.pdf
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