Everyone who enters the ocean, from surfers to swimmers, at some point thinks about sharks. There is something morbidly enchanting about them, something rooted in the part of our psyche that thirsts for a good scare. And whether its 100 times an hour or once a month that our mind comes back to the terrifying prospect, every so often, frequent ocean-users are reminded sometimes in the worst way that we, as a species, are entirely at the mercy of marine predators when in the water. This year, more than any other, there have been an abundance of these reminders.
On November 11, Brian Kang became the ninth person to be attacked off the Pacific coast of North America in 2004, when a huge great white shark, estimated to be 18 feet in length, clamped down on his legs while he was surfing off the North Jetty in Humboldt Bay, California. Thankfully Kang was released and was able to catch a wave back to shore and survive, but the incident made 2004 the most active year ever recorded for great white shark attacks along the Pacific coast, or anywhere in the world.
Surfermag.com thought it would be a good time to talk with a specialist about the factors involved with the rise in attacks, general information about white sharks, and some tips to help us keep next years numbers to a minimum. Ralph S. Collier, author of Shark Attacks of the Twentieth Century, has been monitoring and investigating interactions between humans and sharks since 1962, first with the Office of Naval Research and the Smithsonian Institute, then with the California Department of Fish and Game, and now for his own Web site, www.sharkresearchcommittee.com. What follows is an edited version of our conversation.
SURFERMAG.COM: A more than triple increase in the average of attacks in the past four years is rather alarming to most of us who spend a lot of time in the water. It is probably extremely difficult to pinpoint the factors that contributed to the increase, but what are some of the possibilities?
Ralph S. Collier: First of all, the tripling is in reference to the number of white shark attacks. We have averaged just slightly more than one white shark attack per year during the 20th century. During the first four years of this century we have experienced 16 white shark attacks, which is an average of four shark attacks per year. Which is more than triple in average. But as far as what some of the possibilities are for this increase it could be the result of a number of factors. One is that there could have been an increase in population of ocean-user groups; i.e. there are more divers, swimmers, surfers and kayakers going to the beaches utilizing the ocean, therefore we have more people being placed in a position where they might have an interaction with a shark. The other thing that could be taking place is that the white shark has been protected for the past 10 years. This protection, although not infallible, probably has allowed a larger survivable population, annually, of juveniles. Gill net fishing is much more restricted today than it was 10 or 20 years ago. There are lots of other factors, like an increase in ocean-user groups could mean that there are more people around to observe and report shark activity than before. More sharks being closer to shore this year might have been a result of unusual or anomalous oceanographic conditions.
SURFERMAG.COM: On your Web site you mentioned that the nine attacks on the Pacific coast of North America were the most ever recorded for great white shark attacks anywhere in the world. Are there generally more attacks on the Pacific coast of North America than other places in the world?
Ralph S. Collier: Let me give you a few statistics. From 1852 to 2004, 93 white shark attacks were authenticated from South Africa. Now that's a period of 152 years. Now if we look at Australia, where everyone thinks that you have the highest incidence of white shark interactions with humans, there have been this is according to an e-mail I received from a colleague in New South Wales, who is the head of the South Australian Shark Attack File he informed me that they have, in a period of 213 years, recorded a grand total of 79 authenticated white shark attacks in Australia. In North America, we have a total of 110 authenticated white shark attacks from 1926 to the present.
SURFERMAG.COM: Do you have any theories on why this is?
Ralph S. Collier: The reason that we have more interactions is probably again a multiple faceted reason. Number one, marine mammals have been protected now for right around 30 years. So the marine mammal population is growing, and has been growing by leaps and bounds.
SURFERMAG.COM: And I would assume then that in other places they aren't?
Ralph S. Collier: Other locations, they're probably protected but I don't know that their numbers are as great as they are here. I don't know where the juveniles are pupped in Australia. To be honest with you, I've never been able to get a firm handle on where they catch juvenile white sharks in the 3- and 4-foot range. There just isn't any data on that. But I do know that they've [fishermen] been catching juvenile white sharks from Point Conception down into Mexico since the early 1930s. The adults are being brought into this area because it's a good place for them to give birth. Now, the parent leaves after giving birth because you have to have segregation between the adult and the juvenile, otherwise within a few days of giving birth, the mother will start feeding and shell eat her own young. So the females, generally we see them out at the islands. There are frequently large numbers of them in the spring, in San Clemente, Catalina, the Southern California islands. Then the sharks seem to move northward. We don't have as many reports of sightings down here and they start showing up in Central and Northern California. Well, this is all movement associated with prey. Animals follow their prey. Sharks do what they do based on food and/or mating, and/or giving birth, and when the sharks move north that happens to be the time of the year when we start getting spawns of salmon and steelhead. And these things start occurring along the coastal rivers of Central and Northern California and now we start seeing more white sharks along these areas, because white sharks eat salmon and they also eat seals which come in close to shore to feed on the salmon. So you basically have a circular chain where you have fish coming ashore to go upriver to spawn, you have seals coming in to feed on those fish and then you have white sharks coming in to feed on the fish and the seals. And in the middle of all this, a lot of good places to surf are near rivermouths because the river brings down silt, which creates sandbars, which causes the waves to have nice shape. So its unfortunate that all of these places that these animals go to do what Mother Nature has taught them, happen to be the same places that are good for us to go enjoy our favorite sport.
SURFERMAG.COM: In your book you mention that 60% of great white attacks were from a recurring location. What are some of these locations?
Ralph S. Collier: Some of the recurring locations off the top of my head are the Farallon Islands. Tomales Point in Northern California. In Southern California, some of the recurring locations would be Paradise Cove, Malibu. La Jolla, we've had several attacks in La Jolla. One fatal. There was a fatal attack in Malibu, Paradise Cove, on a kayaker in 1989.
SURFERMAG.COM: I think there's a common misconception that sharks primarily hunt with their sense of smell. What is the primary sense that makes sharks such efficient predators?
Ralph S. Collier: It's an efficient use of a number of sensory systems. Sharks have a lateral line, which for things like explosions or splashing, they can sense displacement of water at quite a distance, using a lateral line and hearing as well. When they get close to an object, lets say they smell blood in the water from a dead whale, they will follow that back to the animal. Depending on water clarity, when they get close enough, vision takes over. Short distances, we believe based on water visibility, white sharks are probably more of a visual predator within 20 to 30 meters of their prey. And that is probably best emphasized by the fact that if you microscopically examine the retina of a white shark eye, you will notice that they have the same ratio of rods to cones as a human. Which means, not only do they have the same acuity that you and I have to determine finite detail on objects, not only up close, but also at distances, but they also have the ability to see colors.
SURFERMAG.COM: What is the largest adult white shark you've observed?
Ralph S. Collier: 19 feet, 3.5 inches, and it weighed 4,680 pounds, I think. The heaviest great white I've ever worked with was a female that was 16 ft., 9 in. and weighed 4,745 lbs.
SURFERMAG.COM: Is there anything you can suggest to surfers who might encounter a great white shark?
Ralph S. Collier: The first thing I would suggest if a shark comes upon you, and you see him, odds are pretty good that its not going to strike you. The reason is that usually predators do not announce themselves to an unsuspecting prey, so he's probably more curious than anything. If you see the animal, try to remain calm; if it's at the surface, try to keep sight of it. Do not make any sudden, quick moves. Keep sight of the animal. When the opportunity presents itself, I would make for shore. Do whatever you have to do to remove yourself from the water as quickly, as quietly, as smoothly as possible. Don't do any excessive splashing. Don't flail your arms in the water and start digging like crazy for the shore. Because that sudden burst of energy and noise might attract the animal and make it a little more curious and think that you might be something that is trying to flee. You basically just need to remain calm and let it check you out. I cant tell you how many dozens upon dozens of reports I get every year of a white shark coming up alongside a surfer and circling the board a couple times and then just swimming off. They're more curious about surfers than they are intent on eating them. White sharks, because of their vision, I do not believe, based on my research, that attacks on surfers are the result of mistaken identity, as it is referred to, which is really a predatory attack. I think some of the attacks on surfers are predatory, but I think the majority of interactions are more out of investigation and curiosity.