Dive Dry with Dr. Bill

#285: The Sharks and the Bees

Sharks have made big waves in the news recently with the fatal attacks on a swimmer off Solano Beach, a California surfer near Ixtapa, Mexico, and and attacks in Fiji and Australia. This will only add fuel to the fires stirred up by some in the media seeking another sensational news story. Of course none of us want to be lower on the food chain than any predator whether it be a shark, a tiger or a crocodile. My condolences go out to the families and friends of these victims. However, when we enter environments where we are not dominant... whether it be the ocean, the jungle or a swamp... we have to be prepared for the unexpected. But just what are the chances we will become victim of such an attack? Actually very, very small as you shall see.

When KNX radio called to interview me the morning of the first attack, I wanted to avoid many of the common statistics we biologists and "shark huggers" throw out about the probability of death from other sources such as honey bees, mosquitoes and coconuts. I also wanted to avoid fueling any possible sensationalism that might develop from this admittedly frightening news story. I explained to them that I was sitting many miles away from the site of the attack, and had no first-hand knowledge so I could only speculate. However, I should briefly touch on the likelihood that one of us would be attacked and killed by "the landlord" here in southern California.

Globally the number of shark attacks on humans by all species each year has ranged from 36 to 79 since 1990. However, fatal attacks were always less than a dozen and as low as just one (last year). Closer to home, there have been only 43 attacks total during that entire period, averaging less than half a dozen a year. Of those attacks, only two were fatal (one each in 2003 and 2004). When you consider how many million people entered the water during those 18 years, the odds of an attack are less than those of winning the lottery (at least for me, since I don't buy tickets). Although the number of great white sharks has probably increased during the last 100 years, the number of attacks per human being has not. In fact, the number relative to our population has decreased and the number of those attacks that are fatal has fallen even more.

During the KNX interview, I speculated that the shark must have been a great white based on the mode of attack. It came from behind and below, forcing the swimmer partially out of the water. Another clue was the fact that the shark had apparently taken both of the swimmers legs into its maw, and nearly severed at least one of them. That suggested a shark in the 12 to 15 foot range to me, and it was later confirmed to be about 15-16 feet by Dr. Richard Rosenblatt of Scripps who was on the scene. Following my segment, some lifeguards suggested it was a blue or mako shark which was highly unlikely. Although blue sharks have been implicated in many attacks, these generally occur in the central and South Pacific where this species may reach 12-18 feet in length. We usually only see the 3-6 foot "young 'uns" in our waters. Based on the International Shark Attack File website, only about 3% of all California fatalities dating back to 1580 were due to blues or makos. Great whites were responsible for 75% of the 96 recorded attacks in that 427-year period, with another 20% by unidentified shark species.

While I feared great whites when I first moved to Catalina in the late 1960's (we had none back in Lake Michigan), and actually stopped diving for about three years after seeing "Jaws," I have had enough experience to realize the fear is largely unfounded. Of the 66 known attacks occurring in California during the entire 20th century, the vast majority of them were on swimmers or surfers. Needless to say, I don't surf! When I dive, I am almost always near the bottom filming critters. Apparently I've had at least one great white swim past me as I filmed giant sea bass with marine artist Wyland. Fortunately, I haven't gained enough weight yet to resemble a seal or sea lion. Until great whites adopt a stealth strategy of burying into the sand and popping out to bite unwary divers, I feel pretty safe since great whites attack from below.

Other statistics are very interesting, albeit a bit skewed. I often tell the lovely lady divers on the King Neptune not to worry since most sharks are "man eaters." Apparently there is some "truth" to that since attacks on males are 15 times those on females. The number of great white attacks are much, much higher for 15-29 year olds than they are for those of us living in the "new 40's" (at least those of us not already in nursing homes where attacks only occur from "land sharks"). The majority of attacks occur from 1:00 to 3:00 pm, although that is also the time of peak human recreational activity and therefore of human exposure.

Oh, and in case you really wanted to know... more people are killed each year by honey bees, mosquitoes jellyfish, falling coconuts, and even falling vending machines (whether you favor Coke, or of the Pepsi generation). The fatality rate from alligator attacks is three times that from sharks. At least we're safe from that here in southern California! The number of fatalities from lightning strikes is 80 times that for shark attacks so I still have reason to fear electrical storms (which were too common in Chicago during my youth).

Compare all this to the odds of attacks against the poor sharks by humans. Various estimates put the number of sharks killed worldwide each year at between 20 and 100 million. Please don't think that you can reduce this number just by avoiding shark fin soup. Although a finger is often pointed at Asian countries for consuming this delicacy, shrimp and other fishing fleets kill a large number of sharks caught as bycatch, especially those using longlines, gill nets or trawls. Keep that in mind when you eat your next wild shrimp cocktail or fish 'n' chips.

Only recently, with the loss of so many sharks and shark species globally, have scientists begun to understand the serious impacts of their absence on ecological systems such as coral reefs. Sharks play critical roles in maintaining the health of many of our biological communities. Without them, ecosystems can sicken and become radically imbalanced.

I'm sure there are many who have seen "Jaws" or watched the increasingly sensationalized "Shark Week." I wish an equal number would watch Rob Stewart's documentary "Sharkwater" which details the serious implications from the over fishing of sharks. I'm very tempted to buy a copy on DVD and invite my friends up to the house to watch this well-received documentary to get "fair and balanced" reporting on my finny friends. Oh, and while you're at it, why not buy a copy of my "Sharks and Rays of Southern California" DVD as well. Yes, I know, a shameless commercial plug... but even I have to eat, and I can assure you it won't be shark fin soup, or even thresher shark steak.

© 2008 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles," "Gentle Giants: Giant Sea Bass," "Common Fish and Invertebrates of the Sea of Cortez" or the new "Sharks and Rays of Southern California" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

The landlord... just a pussy cat compared to the honey bee!

This document maintained by Dr. Bill Bushing.
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