The Great White Sharks of the Farallones
White Sharks in the Sanctuary (Carcharodon carcharias)
Gulf of the Farallones Marine Sanctuary
The Farallon Islands have one of the world’s more significant populations of great white sharks. Located 28 miles off the coast of San Francisco, Southeast Farallones Island is actually comprised of two islands separated by a narrow crevasse. (Southeast Farallon and Maintop or West Island). These islands provide a major nursery for Northern Elephant Seals and other pinniped populations (seals and sea lions). Each fall adult great white sharks return to the islands to feed on the sea lions and seals gathering to pup and reproduce at the islands. This is essential habitat for marine mammals and white sharks and both should be respected when observing from a vessel.
About Sea Stewards Whale and White Shark Sharktoberfest Natural History Tours
These tours are a new development building on the exciting whale watch and Natural History tours conducted through the late summer and fall. As the summer wanes we experience a changing of the guard among the aquatic wildlife near the islands. In the late fall from September through December the islands become the visiting grounds of our local population of Great White Sharks.
It’s the months local surfers call Sharktober!
Our tours are geared towards awareness and education and to celebrate the beauty and importance of white sharks. We book our tours through San Francisco Whalewatch tours in the vessel Outer Limits. The Sharktoberfest Natural History Tours do not chum the waters or otherwise attract white sharks at the Farallones. There is no guarantee of seeing a shark- although we have seen sharks at the surface. What we can guarantee is an unforgettable experience witnessing and learning about the rich wildlife and history of the Gulf of the Farallones. We have seen white sharks at the surface and if we are fortunate we will observe natural feeding events and can approach as close as the regulations permit us. Leading the tours will be our local shark expert David McGuire of Sea Stewards. In addition to conducting a study on several local species of sharks with the California Academy of Sciences, David has been trained under the White Shark Stewardship Project.
About the Sanctuary
Designated in 1981 because of its rich biological diversity, the Gulf of the Farallones National Marine Sanctuary (GFNMS) surrounds the wind-swept peaks of the Farallon Islands off of the Golden Gate. The Sanctuary encompasses over 1,200 square miles of open ocean and coastal waters as well as bays and estuaries—from Bodega Head in Sonoma County all the way down along the San Mateo County coast. The islands in its midst serve as breeding grounds for more seabirds than any other area in the contiguous United States. The Sanctuary contains vital nursery and spawning grounds for many fish and shellfish. At least 36 species of marine mammals have been observed within its borders, including 25 endangered species, such as the blue and humpback whales.
One of the most famous visitors to the Sanctuary is the Great White Shark.
To see the Farallones from the web cam
White Shark Stewardship Project
Resource managers of the Gulf of the Farallones National Marine Sanctuary have developed guidelines for white shark viewing. Our white sharks gather at the islands to feed, and possibly mate. The Shark Watch program has reported pregnant sharks around the islands. Improper tourism practices such as those witnessed in the past and at other locations cause potentially harmful impacts on the sharks including energy loss or physical damage to the animal. The goal of the White Shark Stewardship Project is to protect and conserve the white shark population that uses sanctuary waters.
In March 2009, these regulations went into effect prohibiting white shark attraction and approach in Gulf of the Farallones National Marine Sanctuary. Additionally, the existing white shark attraction prohibition in state waters of the Monterey Bay National Marine Sanctuary was expanded to the entire Monterey Bay Sanctuary.
The regulations for Gulf of the Farallones Sanctuary prohibit, “attracting a white shark in the Sanctuary; or approaching within 50 meters of any white shark within the line approximating 2 nautical miles around the Farallon Islands” external link15 C.F.R. Section 922.82(a)(13). The regulations and supporting rationale are published in the external link Federal Register (73 FR 70499).
The White Shark Stewardship Project is the umbrella for all white shark programs of the Sanctuary, and includes the following project components: 1) Public and boater outreach, 2) Naturalist training, 3) School education programs, 4) Permitting, 5) Monitoring, and 6) Coordinating with the NOAA Office of Law Enforcement
Shark Research in the Sanctuary
Ground breaking research is being conducted on white sharks and other predators by the TOPP program (tagging of Pacific Predators). TOPP consists of a team of Marine biologists, oceanographers, engineers, computer programmers, journalists, graphic designers, educators and others, who are interested in sustainable oceans. NOAA’s Pacific Fisheries Ecosystems Lab, Stanford’s Hopkins Marine Lab, and University of California, Santa Cruz’s Long Marine Laboratory manage the program.
In 2009, the TOPP white shark published a landmark publication Philopatry and migration of Pacific white sharks http://rspb.royalsocietypublishing.org/content/early/2009/10/29/rspb.2009.1155.full The TOPP study utilized satellite tagging, passive acoustic monitoring and genetic tags to study the migration and population structure of white sharks in the northeastern Pacific over the years from 2000-2008.
The tagging study reveals that although these sharks undergo long seasonal migrations covering thousands of miles, and indicate an intriguing dive profile. Data transmitted from the tags indicate the sharks they return to the same local hotspots like the Farallones, Ano Nuevo and a separate sub population down at Guadalupe Island year after year. Comparison of mitochondrial DNA to white sharks from Australia, New Zealand and South Africa suggest that the sharks off northern California are genetically distinct with little or no mixing between the Guadalupe population. It appears that this sub population has become isolated from the rest of the Pacific population some time in the past 150-200 thousand years.
By using acoustic tags, which are detected by stationary receivers scattered around various places in the ocean and San Francisco Bat, the researchers are able to detect more fine-scale movement patterns that are possible with satellite tags. These results showed that the sharks appear at some surprising places – among the Hawaiian Islands and even under the Golden Gate Bridge and into the Bay itself. Yes, there are White shark who visit the Bay.
The Shark Watch Program on the Farallones
One of the longest white shark monitoring studies in the world was initiated by biologists residing on the Farallones as part of the Point Reyes Bird Observatory, a branch of the Fish and Wildlife Service. In 1987 PRBO biologists Peter Pyle, Scot Anderson and others began documenting and observing shark attacks from atop the island at the Farallon lighthouse. After a brief hiatus, thanks to one semi fictional kiss and tell novel, the Sharkwatch has resumed, taking photographs to compare individuals and observing feeding incidents.
The two main focus areas of PRBO’s White Shark Research at the Farallon Islands in the past included Individual Shark Identification and Shark Watch and Population Monitoring. Currently, PRBO is only continuing the Shark Watch and Population Monitoring Project.
In 1987 PRBO biologists began documenting and observing shark attacks from atop the island at the Farallon lighthouse. Here is a paragraph from an article that appeared in PRBO’s Observer in 1992.
Successful biological inquiry requires a healthy combination of both focused technical research and ample field observation of a subject species. Turning our attention to the latter, we standardized and expanded our observation program in 1987 by stationing one to two observers at the lighthouse during all daylight hours in fall, specifically to search for shark activity. Initiated by Scot Anderson, the shark watch has now produced five years of fall surveillance. During this time we have witnessed 40-60 predatory events per year, an increase from a previous maximum of twelve in 1986. By standardizing our observations, we can determine whether this perceived increase in shark activity is real or simply the artifact of enhanced observer awareness at Southeast Farallon Island It will also enable us to compare the occurrence of attacks with oceanic conditions, such as temperature, salinity, and clarity, which show wide inter-annual variation in the vicinity of the Farallones. Preliminary analyses suggest, for example, that attack frequency increases with colder sea surface temperatures in fall, disputing a widely believed theory that warmer waters (such as those associated with El Nino) bring more sharks into our region. Our findings also suggest that white shark attacks are positively correlated with water turbidity: perhaps the lack of visibility impairs the ability of pinnipeds to detect and escape the sharks. As both colder water and higher turbidity result from coastal upwelling, though, one or both of these correlations may be coincidental. We will soon perform multivariate analyses to see which oceanic conditions have the greatest effect on shark behavior.
Using a standardized method, biologists continue to monitor shark attacks, recording frequency and location. This provides us with information on environmental effects, population trends, and behavior patterns of prey and predator.
One of the goals of our research is to minimize shark/human attacks. Here are some suggestions that may help to prevent shark attacks on humans. (these are speculations based on our research and observations of shark/human encounters):
PRBO TIPS FOR SURFERS TO AVOID BEING CHOMPED
- Avoid rocky drop-offs beyond break. (e.g. Davenport, Salmon Creek)
- Stay in water < 20ˇ˝ deep (sharks prefer hunting in 20-90′ depths)
- Avoid areas near pinniped haul-outs (Aˇ˝o Nuevo, Jenner)
- Look for large boils (not wave/rock related) caused by the sharks powerfultails.
- Pay attention to spooked feelings (we may have a 6th sense about sharks)
- Wear a pin-striped wetsuit (i.e., look as little like a seal as possible)
- Surf with a buddy
White Shark Natural History
Although we know more about white shark attacks from the media, Shark Week and Jaws, we know very little about the shark itself. Sharks in general are difficult to study and until the last few decades have not been a focus of research. Recent studies have revealed exciting new revelations on the behavior and adaptations of sharks. White Sharks White sharks (Carcharodon carcharias) are the ocean’s largest predatory sharks. The occasional encounter with humans (and movie producers) has made them the most famous. Although they can grow to almost 21 feet (7 meters), the length of an average shark is closer to 15 feet (5 meters); they weigh about 1,500 pounds (700 kg). White sharks, like some other fish such as salmon sharks and tuna, are warm-bodied — that is, parts of their bodies can be warmer than the cold water in which they swim.
In the eastern Pacific, white sharks can be found from Alaska to Mexico, but you don’t often see them north of Washington State. These sharks frequent haul-out sites for marine mammals, their primary food. We used to believe they roamed only along the California coast. But the Topp tags show that they travel regularly from California to Hawaii and back each year in an extraordinary migration. Juvenile white sharks are found in the Southern California Bight, which appears to be an important nursery ground.
The World Conservation Union lists white sharks as vulnerable. Concerns for white shark populations have led to their protection in Californian and Mexican waters, and there are protections in South Africa, New Zealand and Australia. However, these species cross international borders and are know to fall prey as bycatch and by shark finning. To ensure their long-term survival, we need much more information about where these sharks go to feed and breed. The recent tagging results indicate how little is actually known about white sharks. Also, white sharks will also provide a valuable comparison to results from salmon and mako sharks that are also capable of elevating their body temperature.