Nav: Home

Great white shark population in good health along California coast, UF study finds

June 16, 2014

GAINESVILLE, Fla. --- The Great White Shark is not endangered in the Eastern North Pacific, and, in fact, is doing well enough that its numbers likely are growing, according to an international research team led by a University of Florida researcher.

George Burgess, director of the Florida Program for Shark Research, said the wide-ranging study is good news for shark conservation. The study, to be published June 16 in the journal PLOS ONE, indicates measures in place to protect the ocean's apex predator are working.

Scientists reanalyzed 3-year-old research that indicated white shark numbers in the Eastern North Pacific were alarmingly low, with only 219 counted at two sites. That study triggered petitions to list white sharks as endangered.

"White sharks are the largest and most charismatic of the predator sharks, and the poster child for sharks and the oceans in general," said Burgess, whose research program is based at the Florida Museum of Natural History on the UF campus. "If something is wrong with the largest, most powerful group in the sea, then something is wrong with the sea, so it's a relief to find they're in good shape."

The National Marine Fisheries Service (NMFS) was petitioned to add white sharks to the endangered species list but declined, based on its own research, bolstered by a preview copy of the study by the international team, said Heidi Dewar, a fisheries research biologist. NMFS estimated the Eastern North Pacific population at about 3,000 sharks.

"We determined there were enough animals that there was a low to very low risk of extinction, and in fact, most developments suggest an increasing population," Dewar said.

Burgess and his colleagues assembled a 10-member team with expertise in all facets of shark biology: demography, population dynamics, life history, tagging and movements, fishery biology and conservation, and mathematical modeling. The team has studied sharks from Florida to California, Alaska to Hawaii, and around the globe.

White sharks can be notoriously difficult to count. They are highly mobile and migratory and group themselves by age, sex and size. Unlike marine mammals, they do not surface to breathe. Some gather at aggregation sites to dine on seals, others stay at sea, dining on fish. Most tagging studies use photographic tags - pictures of unique markings, such as nicks on fins or scars - and those markings can change over time.

Population estimates, however, are important to conservation. Sharks are sensitive to overfishing, both as bycatch for fisherman seeking other fish and as targets for sport or in areas where shark meat is a delicacy. White sharks are protected in many areas internationally, including the west coast of the United States, but because they swim in and out of jurisdictions, they are still vulnerable, and the older study raised concerns.

For their reanalysis, the international team examined the two aggregation sites where the earlier count was obtained, the Farallon Islands and Tomales Point, which attract seals and the sharks that feed on them. They found that the sub-populations at both sites were so fluid, with both resident and transient sharks, that it would not be possible to extrapolate a total population number. To get a better picture of the white shark population in the Eastern North Pacific, the team decided to examine several other known aggregation sites, from Mexico into British Columbia and Alaska.

The team also conducted a demographic analysis to account for all life stages for the sharks at Farallon Islands and Tomales Point and found that the total population is most likely at least an order of magnitude higher - rather than just over 200 sharks there likely were well over 2,000.

"The listing of a species as 'endangered' places substantial demands on governments," Burgess said. "Listing species that are not under the threat of biological extinction diverts resources away from species genuinely at risk. We want to use our resources for the neediest species."

The earlier study also compared shark population numbers with other apex predators, such as polar bears and killer whales. That study, however, ignored the differences in the community structures for those three species and the fact that polar bears and whales, as mammals, are easier to count.

"That we found these sharks are doing OK, better than OK, is a real positive in light of the fact that other shark populations are not necessarily doing as well," said Burgess, a co-founder of the Shark Specialist Group of the International Union for the Conservation of Nature. "We hope others can take our results and use them as a positive starting point for additional investigation."
Writer: Cindy Spence,, 352-846-2573

Source: George Burgess,, 352-318-3812

University of Florida

Related Conservation Articles:

Targeted conservation could protect more of Earth's biodiversity
A new study finds that major gains in global biodiversity can be achieved if an additional 5 percent of land is set aside to protect key species.
Conservation endocrinology in a changing world
The BioScience Talks podcast ( features discussions of topical issues related to the biological sciences.
Marine conservation must consider human rights
Ocean conservation is essential for protecting the marine environment and safeguarding the resources that people rely on for livelihoods and food security.
Mapping Biodiversity and Conservation Hotspots of the Amazon
Researchers have used remote sensing data to map out the functional diversity of the Peruvian Andes and Amazon basin, a technique that revealed hotspots for conservation.
Mapping biodiversity and conservation hotspots of the Amazon
Researchers have used remote sensing data to map out the functional diversity of the Peruvian Andes and Amazon basin, a technique that revealed hotspots for conservation.
Internet data could boost conservation
Businesses routinely use internet data to learn about customers and increase profits -- and similar techniques could be used to boost conservation.
Why conservation fails
The only way for northern countries to halt deforestation in the South is to make sure land owners are paid more than it costs them to conserve the forest.
Visitors to countryside not attracted by conservation importance
Countryside visitors choose where to go based on the presence of features such as coastline, woodland or abundant footpaths, rather than a site's importance to conservation, according to new research.
In communicating wildlife conservation, focus on the right message
If you want people to care about endangered species, focus on how many animals are left, not on the chances of a species becoming extinct, according to a new study by Cornell University communication scholars.
New partnership to boost Asia-Pacific conservation
The University of Adelaide and global organization Conservation International (CI) today announced a strategic partnership that will help boost conservation efforts in the Asia-Pacific region, including a global conservation drone program.

Related Conservation Reading:

Resurrection Science: Conservation, De-Extinction and the Precarious Future of Wild Things
by M. R. O'Connor (Author)

**A Library Journal Best Book of 2015 **
**A Christian Science Monitor Top Ten Book of September**

In a world dominated by people and rapid climate change, species large and small are increasingly vulnerable to extinction. In Resurrection Science, journalist M. R. O'Connor explores the extreme measures scientists are taking to try and save them, from captive breeding and genetic management to de-extinction. Paradoxically, the more we intervene to save species, the less wild they often become. In stories of sixteenth-century galleon excavations,... View Details

The Future of Conservation in America: A Chart for Rough Water
by Gary E. Machlis (Author), Jonathan B. Jarvis (Author), Terry Tempest Williams (Foreword)

This is a turbulent time for the conservation of America’s natural and cultural heritage. From the current assaults on environmental protection to the threats of climate change, biodiversity loss, and disparity of environmental justice, the challenges facing the conservation movement are both immediate and long term. In this time of uncertainty, we need a clear and compelling guide for the future of conservation in America, a declaration to inspire the next generation of conservation leaders. This is that guide—what the authors describe as “a chart for rough water.”

... View Details

The Rise of the American Conservation Movement: Power, Privilege, and Environmental Protection
by Dorceta E. Taylor (Author)

In this sweeping social history Dorceta E. Taylor examines the emergence and rise of the multifaceted U.S. conservation movement from the mid-nineteenth to the early twentieth century. She shows how race, class, and gender influenced every aspect of the movement, including the establishment of parks; campaigns to protect wild game, birds, and fish; forest conservation; outdoor recreation; and the movement's links to nineteenth-century ideologies. Initially led by white urban elites—whose early efforts discriminated against the lower class and were often tied up with slavery and the... View Details

An Introduction to Conservation Biology
by Richard B. Primack (Author), Anna Sher (Author)

New coauthor Anna Sher joins longtime author Richard Primack in creating a book that combines the readability of Primack's A Primer of Conservation Biology with the depth and coverage of his larger textbook, Essentials of Conservation Biology. The result is a book well suited for a wide range of undergraduate courses, as both a primary text for conservation biology courses and a supplement for ecological and environmental science courses.

Using the chapter framework of the current Primer as a springboard, the authors have added three chapters focused on... View Details

Conservation: Linking Ecology, Economics, and Culture
by Monique Borgerhoff Mulder (Author), Peter Coppolillo (Author)

Nearly 90 percent of the earth's land surface is directly affected by human infrastructure and activities, yet less than 5 percent is legally "protected" for biodiversity conservation--and even most large protected areas have people living inside their boundaries. In all but a small fraction of the earth's land area, then, conservation and people must coexist. Conservation is a resource for all those who aim to reconcile biodiversity with human livelihoods. It traces the historical roots of modern conservation thought and practice, and explores current perspectives from evolutionary... View Details

2015 International Energy Conservation Code
by International Code Council (Author)

For the most current information on energy conservation code requirements, refer to the 2015 INTERNATIONAL ENERGY CONSERVATION CODE. This highly beneficial resource fosters energy conservation through efficiency in envelope design, mechanical systems, lighting systems, and through the use of new materials and techniques. In the residential provisions, the inclusion of the Energy Rating Index Compliance Alternative as another compliance path adds more flexibility to the 2015 IECC. With this comprehensive and cutting edge coverage, it is a critical component of a user's code books. View Details

2018 International Energy Conservation Code
by International Code Council (Author)

The IECC addresses energy efficiency on several fronts including cost savings, reduced energy usage, conservation of natural resources and the impact of energy usage on the environment. Key changes include: Log homes designed in accordance with the standard ICC 400, Standards on the Design and Construction of Log Structures, are exempt from the building thermal envelope requirements of the IECC. The maximum allowable fenestration U-factors in Table R402.1.2 (for the prescriptive compliance path) for climates zones 3 through 8 have been reduced from the values in the 2015 edition. The... View Details

Conservation Science: Balancing the Needs of People and Nature, Second Edition
by Prof. Peter Kareiva (Author), Prof. Michelle Marvier (Author)

Now is the time for conservation science―a mission-oriented scientific enterprise that seeks to protect nature, including Earth’s animals, plants, and ecosystems, in the face of unprecedented human demands upon the planet. Conservation scientists apply principles from ecology, population genetics, economics, political science, and other natural and social sciences to manage and preserve nature. The focus of this textbook is first and foremost on protecting nature and especially Earth’s biota. It also contains a heavy emphasis on highlighting strategies to better connect the practice... View Details

Conservation Is Our Government Now: The Politics of Ecology in Papua New Guinea (New Ecologies for the Twenty-First Century)
by Paige West (Author)

A significant contribution to political ecology, Conservation Is Our Government Now is an ethnographic examination of the history and social effects of conservation and development efforts in Papua New Guinea. Drawing on extensive fieldwork conducted over a period of seven years, Paige West focuses on the Crater Mountain Wildlife Management Area, the site of a biodiversity conservation project implemented between 1994 and 1999. She describes the interactions between those who ran the program—mostly ngo workers—and the Gimi people who live in the forests surrounding Crater Mountain.... View Details

Essentials of Conservation Biology
by Richard B. Primack (Author)

Essentials of Conservation Biology, Sixth Edition, combines theory and applied and basic research to explain the connections between conservation biology and ecology, climate change biology, the protection of endangered species, protected area management, environmental economics, and sustainable development. A major theme throughout the book is the active role that scientists, local people, the general public, conservation organizations, and governments can play in protecting biodiversity, even while providing for human needs.

Each chapter begins with general ideas and... View Details

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Consequences Of Racism
What does it mean to be judged before you walk through the door? What are the consequences? This week, TED speakers delve into the ways racism impacts our lives, from education, to health, to safety. Guests include poet and writer Clint Smith, writer and activist Miriam Zoila Pérez, educator Dena Simmons, and former prosecutor Adam Foss.
Now Playing: Science for the People

#465 How The Nose Knows
We've all got a nose but how does it work? Why do we like some smells and not others, and why can we all agree that some smells are good and some smells are bad, while others are dependant on personal or cultural preferences? We speak with Asifa Majid, Professor of Language, Communication and Cultural Cognition at Radboud University, about the intersection of culture, language, and smell. And we level up on our olfactory neuroscience with University of Pennsylvania Professor Jay Gottfried.