Happy Sharktober.
Sharktober is the fall months when the adult great white sharks reappear on the west coast of North America after around six months of absence. After migrating thousands of miles roundtrip between North America and an oceanic area east of Hawaii called the “White Shark Cafe”, the mature white sharks return in late summer to their feeding grounds off the Central California coast.
This is also a period of maximum probability to see or encounter an adult white shark along the west coast, and the time of peak human-white shark interactions (e.g. attacks). It is also a time when Shark Stewards celebrates sharks and hosts Sharktoberfest celebrations, and motivates the public to embrace their importance and help protect endangered sharks and rays from extinction.
Surfers along the coast have been observing more sharks for years during the months of September- November, and we call these months Sharktober. Most of the human- white shark encounters occur in our area during these months and the press generates a lot of negative attention, so we decided to celebrate, not hate, sharks, and branded our outreach efforts Sharktober. The Bay Area is centered in what is called the Red Triangle– where a large number of white shark attacks on humans occur in California- mostly in the fall months.
Shark Stewards uses this season to raise awareness that the white sharks live here, and that people should be aware of increased risk and act in a safe and rational manner when recreating or working in the ocean. This period is a time of higher risk of an encounter between ocean-goers and large white sharks along the coast of California and Baja. It is also a time to learn more about the role of sharks in the ocean, threats to sharks globally, and how humans can live near sharks, reduce risk of an attack, and help us protect other, and the less famous species of sharks that are critically endangered.
WHERE DID THE SHARKS GO?
With satellite tagging, scientists have demonstrated that in late August and early September the mature white sharks return to our coastline after an incredible migration from over 1200 miles west. Previously, researchers with the Point Reyes National Bird Observatory (now Point Blue) on Southeast Farallon Island (SEFI) started documenting an increase in white shark observations about twenty five years ago. Early observations of shark- elephant predation events began at SEFI in the early 90s, and tagging and identifying individual sharks by photo ID established the sharks disappear for long periods of time from winter to fall. But it wasn’t until Stanford’s TOPP lab started tagging sharks using pop-up satellite (PSAT) tags around 2005 that we learned the large sharks leave our coastal feeding areas and swim offshore to what is called the White Shark Cafe. This region a several hundred miles west of Hawaii serves as a mixing area between the mature white sharks off the Farallon islands, Ano Nuevo, Pt Reyes and the Baja sub population south including Guadalupe Island. From diving profiles collected on a 2021 expedition to the White Shark Cafe’, it appears the sharks are diving deeper than previously considered, and potentially feeding on giant squid but also opportunistically on other marine mammals. It is also likely that the sharks are breeding there. This region is on the high seas where there is very little protection for these and other sharks, from incidental take as bycatch and IUU fishing, particularly for the shark fin trade.
DONT BE AFRAID OF SHARKS, BE AFRAID FOR THEM
Today one third of sharks and rays are threatened with extinction. In my lifetime we have seen some populations decline to less than 10% of many of the large oceanic sharks original population. Some predictions place outright extinction in another thirty years at the rate we are fishing. This is driven largely by overfishing and the shark fin trade. As a result of overfishing, shark numbers have declined by more than 70% over the last 50 years, with an associated loss to the biodiversity and ocean ecosystems.
WHY SAVE SHARKS?
Sharks play an integral role in keeping our ocean healthy and ecosystems intact. Sharks eat the sick, the stupid and the slow, maintaining other species populations, controlling disease and shaping healthier genes in their prey populations. Learn about trophic cascades in our film Sharks Stewards of the Reef. The mere presence of sharks can cause prey to act differently. The threat of a shark causes prey to be healthier, as sick and dying fish are easily removed from the ecosystem via sharks, stopping the spread of disease amongst the fish population. In turn, this makes fisheries more bountiful. Sharks also stop prey from becoming overpopulated, directly contributing to the health of the entire ecosystem. If you remove these key predators from their environment, it will have a rippling, catastrophic effect down the entire food chain. They also are a factor in the carbon cycle for the ocean. Aside from eating and processing carbon, sharks and other large marine animals sequester large amounts of carbon in their bodies. When sharks are removed, there is that much less carbon kept in the ocean, furthering the effects of global warming. It is essentially impossible to have a healthy ocean without having healthy populations of sharks.
Sharks are worth more alive than dead. Divers and photographers from around the world are seeking sharks, and supporting local economies, including people who might make a living fishing them.
Like many sharks, we don’t know exactly how large the population is. Many population estimates of sharks come from fishing. Fishing records suggest that the Northeast Pacific population prior to industrial fishing was much greater than now, but we don’t know what that level was. We don’t really know how many white sharks exist in this population today or their complete range. Sharks are very difficult to study and count. One recent study based on photographic observations and a statistical model suggests less than 300 adult and subadult white sharks in the two major aggregations in California. Coupled with a similar prediction of about 150 off Guadalupe Mexico, this low population estimate raises concern among conservationists and fisheries managers. Although this doesn’t include baby and young sharks, and the sharks that are not mature enough to migrate, it suggests the Northeast Pacific population is small. Although we know this population has had impacts from fishing, and is still experiencing losses in gill nets, off shore in longlines and the depredations of the shark fin trade, we still don’t know how many there are, or how many we are losing. It raises conservation concerns, because as apex predators, sharks are critical for the balance and health of fish and marine ecosystems. We also know that most populations of large sharks have plummeted in the past 50 years, and many species are threatened or endangered. Globally it has been estimated that white sharks number around 3000-5000 between the main population site, with perhaps 1500 in our population, or an extreme high of 3000 by another estimate. Protected in California since 1994 and in all US waters since 1997. As a result of fifty years of protection, the population in the Northeast Pacific has been slowly increasing.
Risk of Shark Attack
The increase in large white sharks correlates with the calving season of their favorite prey- elephant seals and we see hot spots of sharks around these seal colonies e.g. the Farallones, Ano Nuevo, and the Channel Islands. Human – white shark interactions also increase during these months. (We prefer to call them encounters or interactions and not attacks.) Water enthusiasts should practice caution- especially around seal colonies. Surfing or diving in buddy pairs is advisable. There is now a warning system when sharks are seen near the coast. Through community science we are encouraging public observations through our Shark Watch database, and we started an iNaturalist shark project. Though our outreach activities, we have developed recommendations to avoid shark encounters and communicate risk reduction.
However, the risk of shark attack is very, very low. A Stanford study estimated that the risk of a white shark attack fatality on a surfer- the highest risk activity- is around 1 in 17 million. In California, on average a person is bit once every three years by a white shark, with mortality around one in every 14 years, according to data compiled by the California Department of Fish and Wildlife since 1950. In contrast number of humans killed by handguns in California is 3500 in a single year, according to the National Center for Health Statistics.
What really is Sharktober then?
Sharktober is a celebration of white sharks, but it is a time to reflect on the importance of sharks and the health of the ocean we share. Shark Stewards launched Sharktober and Sharktoberfest celebrations in 2008 to celebrate the return of the white sharks to our Sanctuary offshore, and to educate and motivate the public to protect sharks. The first campaign was to drive support for the successful California Shark Fin Ban introduced by Shark Stewards. Since that time we have used these events with our partners at the California Academy of Sciences, the Gulf of the Farallones National Marine Sanctuary, the California Coastal Conservancy and other NGOS and agencies to reach over 100,000 people in the Bay Area and Southern California.
Sharktober is also a time for ocean goers in the central coast region to practice caution. We use Sharktober to turn the negativity of the press and the poor impression the public has about white sharks and instead try to bring awareness around the importance of sharks to marine ecosystems, and why we should protect them. That’s why we use Sharktoberfest events as a celebration of sharks and to increase protection for endangered species.
White sharks are elegant, and consummately adapted to their ecological niche. To see them in their natural environment is truly a gift from nature.
Each Sharktober, Shark Stewards leads unique wildlife viewing opportunities in the Greater Farallones National Marine Sanctuary to SE Farallon Island. Passengers on these day-long tours learn about the history and natural history of the Farallon Sanctuary and Islands, and observe and photograph seabirds, sunfish, blue, fin, gray, humpback whales, orcas and several species of sharks, including a rare sighting of a great white shark!
Learn more and join us at www.sharkstewards.org.