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Wednesday, October 01, 2008

Are More Mid-Size White Sharks Remaining in Malibu Waters?

• Theory Suggests that Increased Sea Lion Numbers Mean More 7-to-12-Footers Do Not Leave the Area •

BY ANNE SOBLE


The traditional thinking about the presence of great white sharks off Malibu is that the warmer water temperatures and paucity of larger members of the pinniped family meant that the species headed for more hospitable climes at the end of the juvenile stage of about six feet or so in length.
However, there is growing support for the notion that an increased local pinniped population—aquatic carnivorous mammals with finlike flippers, in Malibu’s case, predominately sea lions and seals—results in greater likelihood that white sharks will remain in the area through adolescence, when they can grow to 12 feet in length and pose increased risks in human encounters.
Adult whites, 13 to 21 feet in size, prefer a diet of the larger pinnipeds, especially elephant seals, which are farther offshore and north of Malibu in a constant environment that provides optimum conditions for survival, the apex predator’s primary goal.
The latest flurry of public exchanges about the sea lion population’s connection to increased mid-size white shark presence off Malibu was triggered by a recent posting on the Shark Research Committee Web site, regarding an alleged sighting of the taking of a sea lion by a white in local waters two weeks ago.
The Shark Research Committee is a tax-exempt nonprofit founded in 1962 with an emphasis on shark behavior, especially the recording of attacks on humans. Sharks are respected as evolutionary marvels of marine predation. Their feedings are termed “predatory attacks.”
SRC is overseen by Ralph Collier, who is generally acknowledged to have extensive expertise on whites, although some academic research scientists think his emphasis on human encounters is occasionally sensationalized. However, because of his knowledgeability and ongoing research, they are reluctant to be openly critical.
Collier, who spoke at length with the Malibu Surfside News this week, says the “Jaws” component is inevitable in any great white shark discussion because the 1974 novel and 1975 film sparked intense interest in great white sharks, and activated the public perception of them.
He said the best-seller and movie also spurred intensive hunting of the whites that led to the need for laws to protect them.These laws have been in effect for the last 17 years.
Discussed in conjunction with the Marine Mammal Protection Act that he says led to the growth of the sea lion population, Collier thinks that “only in time will we see the actual cause and effect of this legislation on the balance of nature.”
Collier is fascinated with sharks and can metamorphose into a human encyclopedia when questioned about them. SRC relies on grants and fund-raising. Volunteers provide most of the sightings and other incidents posted on his blog.
The post of the Malibu sighting on SRC’s Pacific Coast Shark News Web site was subsequently picked up by a number of outdoor and marine-related blogs.
It follows verbatim:
“On September 21, 2008 Gina S. and her husband were walking along the beach below the RV park located between Pepperdine University and Paradise Cove near Malibu. It was about 5 p.m. with a sunny sky and a slight breeze. Gina reported: ‘While walking along the beach, my husband and I observed three sea lions 30–40 yards from shore with a small pod of dolphins about 20 yards to the east of the sea lions. The dolphins seemed to be remaining in the same location, possibly feeding. There was one lone sea lion at the surface about 30 yards south of the others. While looking at the lone sea lion, suddenly the huge head of a great white shark surfaced next to the seal and took a large bite out of the animal. The shark was dark grey and at least 10–12 feet in length with a dorsal fin 12–16 inches high. The attack occurred just beyond the forming waves and lasted only a minute or less. Following the initial bite, there was a lot of splashing and then all went quiet. Sea gulls began diving on the attack site, as if they were feeding. The shark submerged, and neither the shark, nor the bitten sea lion, were observed again.”
Collier postscripts the observation, as he does all of his shark reports, with, “Caution should be exercised when utilizing this location for your ocean water activities. Please report any shark sighting, encounter, or attack to the Shark Research Committee.”
When The News emailed Collier to inquire whether it was possible to speak with the woman who filed the report, he emailed back, “I have contacted Gina S. about your request and have provided your contact information.”
When Collier called The News offices this week, he expressed disappointment that the woman had not called, and said he would contact her again because he wants to eliminate any doubts people might have about the authenticity of the sighting.
Collier said, “There’s no doubt in my mind that she witnessed what she said she did.” Although most of the posted reports on his blog include last names, he said she did not want hers used.
If there are still skeptics, he said, “People need to get over the fact that white sharks are out there. They don’t want anything that upsets their notion of how things should be.”
Collier reiterated that “historically, adult white sharks have been infrequent visitors to Southern California, excluding adult females pupping in early spring.” These larger females then head north.
However, he is a booster of the theory that the growth of the pinniped population in Southern California now provides a year-round source of food supply for the apex predators in the mid-size range.
Collier directly correlates the growth with the passage of the Marine Mammal Protection Act in 1972.
Then when the movie “Jaws” came out and white shark numbers were decimated by hunting (a jaw might fetch $25,000), laws were passed in 1993 and 1997 to protect them.
Collier says, however well intentioned, these artificial protections are throwing off natural checks and balances.
The SRC founder said, “The white shark attack on Vic Calandra’s surfboard last year off Malibu suggested that at least some of the larger sharks are remaining in our area.”
The “Calandra attack” involved two paddleboarders at a competition in July 2007 who fought off a mid-size white by hitting it on the head and the nose with their paddles.
At the time, some Malibu officials expressed concern that the Monterey Bay Aquarium shark holding pen, which appears off Point Dume every summer, might be attracting larger sharks, but MBA scientists do not bait the water and obtain live juvenile whites caught by area fishers.
There were a number of witnesses to the Calandra incident, but that is not always the case with Pacific Coast Shark News postings, as the Sept. 21 Malibu sighting illustrates.
One previous posting that was challenged involved Orange County lifeguards who said a shark posting that alleged a white shark attack occurred off Huntington Beach last March was a hoax. But Collier says, “I stand by the reliability of that account.”
Collier doesn’t waver from his position that the local nutritional environment is keeping larger sharks off the Malibu coast longer. He says a recent census count for the state’s pinniped population puts it at over 300,000.
Until a white reaches about nine feet in length, it is primarily a fish feeder, with occasional carrion added to the menu. After that the pinnipeds become the menu item of choice.
The founder of the Shark Research Committee is the author of “Shark Attacks of the 20th Century: From the Pacific Coast of North America,” in which he details more than 100 attacks between 1926 and 1999.
The book includes data indicating that shark attacks can occur at any time of the day or the year, but there are months, water temperatures and activities that make them more likely. This month is one of those times.
Still, witnessed feeding attacks by white sharks are rare, let alone witnessed attacks on humans, especially in Southern California waters.
Monterey Bay Aquarium research indicates that the adolescent sharks it has released have headed south of California to warmer waters with ample food supplies.
But Collier thinks there are probably 100 encounters with white sharks every month off the Southern California coast. The humans who are involved are just not aware that they are taking place.
He urges people to trust their instincts in the ocean. ”If you’re in the water and you get an uneasy feeling, act accordingly. In my 45 years of research, attack victims nearly always say they sensed something before an encounter.”
Collier believes that no one should ever go in the ocean alone, and adds, “Don’t set yourself up to be a target; don’t wear bright colors or jewelry that flashes. Sharks have very good visual acuity.”
But as one local surfer told The News, “We know that larger sharks are out there. But considering all of the other risks in life, that’s not going to keep us out of the water.”

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