Endangered Status Sought for Great White Sharks off US West Coast
SAN FRANCISCO, CA- Oceana, the Center for Biological Diversity, and SharkStewards filed a scientific petition with the National Marine Fisheries Service in Washington DC seeking to protect the US West Coast population of great white sharks under the Endangered Species Act. This week, they will also seek protection under California’s Endangered Species Act. New findings show the numbers of adult great white sharks off the coast of California and Baja California, Mexico are alarmingly low. This unique population is on the brink of extinction because of its low population size and the ongoing threats it faces from human activities.
“The new science set off alarm bells for all of us, as no one expected the population to be so dangerously low,” said Oceana’s California Program Director, Dr. Geoff Shester. “Great White sharks are powerful allies keeping our oceans healthy, and they need us to protect them far more than we should fear them.”
Great white sharks found off the U.S. West Coast are part of the Northeastern Pacific population, genetically distinct and isolated from all other great white sharks around the globe. In 2011, new scientific studies by Taylor Chapple et al1 and Oscar Sosa-Nishizaki et al2 produced the first population estimates of West Coast adult and sub-adult great white sharks, together totaling fewer than 350 sharks– far lower numbers than researchers expected, presenting an inherently high extinction risk. The continued existence of white sharks is also hampered by their low reproductive output, slow growth rate, late maturity, and high mortality rates during the first year.
Deadly gillnets capture and kill great white sharks, and are presently the leading threat to their survival.
While their direct capture for sale is prohibited off the coasts of California and Mexico, young great white sharks are killed as incidental bycatch in commercial fishing. Set and drift gillnets–which together target California halibut, white seabass, thresher sharks and swordfish–are responsible for over 80% of the reported young white sharks caught in their nursery grounds. These fisheries have very low observer coverage, meaning more white sharks are caught than what is reported.
“The fierce great white shark is no match for gillnets that are like curtains of death for marine animals. There are so few of these majestic sharks left in our waters, they urgently need protections,” said Catherine Kilduff, attorney for the Center for Biological Diversity.
1 Chapple, et al. (2011). “A first estimate of white shark, Carcharodon carcharias, abundance off Central California.” Biology Letters 7(4): 581-583.
2 Sosa-Nishizaki, et al. (2012). “Problems with Photo Identification as a Method of Estimating Abundance of White Sharks, Carcharodon carcharias: An Example from Guadalupe Island, Mexico”. In Domeier (Ed.): Global
Perspectives on the Biology and Life History of the White Shark, CRC Press.
Young great white sharks off the Southern California coast are also found to have the second highest mercury level on record for any sharks worldwide, six times higher than levels shown to cause physiological harm to other ocean fish species. In addition, these sharks had the highest levels of the contaminants PCB and DDT in liver tissue observed in any shark species reported to date globally.
“These majestic predators are vital for the health and balance of our ocean ecosystems,” said David McGuire, Director of SharkStewards. “Even the removal of one sexually mature individual from a population this small can have serious impacts on the population as a whole. They need stronger protection immediately.”
Great white sharks are a critical part of the ocean ecosystem, playing an important top-down role in structuring the ecosystem by keeping prey populations in check, like sea lions and elephant seals. The presence of great white sharks ultimately increases species stability and diversity of the overall ecosystem. An Endangered Species Act listing will afford the sharks protections from key threats and garner funding for research to better understand the status and threats to this distinctive population of white sharks.
Oceana is the largest international advocacy group working solely to protect the world’s oceans. Oceana wins
policy victories for the oceans using science-based campaigns. Since 2001, we have protected over 1.2 million square miles of ocean and innumerable sea turtles, sharks, dolphins and other sea creatures. More than 500,000 supporters have already joined Oceana. Global in scope, Oceana has offices in North, South and Central America and Europe. To learn more, please visit www.oceana.org.
The Center for Biological Diversity is a non-profit, public interest environmental organization dedicated to the protection of native species and their habitats through science, policy, and environmental law.