Probability of a shark attack - a statistical fallacy?

[Saturation]

Therefore, I think the actual probability of a shark attack should be based on those who assume the risk - those who dive in areas where sharks are known to make appearance. Again, I would need help from a statistical wiz, but shouldn't the probability be something like the number of fatalities (or injuries) per year divided by the aggregate number of diving hours spent per year by the divers worldwide in shark-appearing areas, thus the result being something like 0.00** percent per each hour you spend under water in a shark-appearing area? Of course, I'm not assuming there would be readily available data on the amount of time the divers spend each year worldwide, but isn't that also part of statistics - making a reasonable assumption?

Has there been an effort to come up with this kind of numbers? Whatever the result, it will not stop me from making my next diving trip, but I want to put things in perspective and see what are the real odds that I'm facing.

Its been difficult to establish the denominator, the population at risk, in terms of more factual numbers. How many divers, swimmers, snorkelers, surfers etc., are there in the water that are exposed to the risk of attack.

However, this much is certain , there are under 80 attacks in the US annually. This is almost the same number of deaths reported in DAN's accident report annually. A rough risk for dying via scuba, all causes, is around 1/10,000 divers or 1/100,000 dives, depending on the denominator.

It would seem that at most the risk of shark attack related fatality is at least that amount.

Then look at whom the sharks attacks, and you'll see that under 25% of reported attacks are on scuba divers. Thus, you can reduce the risk number by at least 75%.

In reality, it must be modified substantially as not all bodies of water have sharks ... such as fresh water bodies like quarries and rivers [although there is a risk of alligator bite in Florida.]

The risk rubric you suggests would be a nice statistical exercise, like a once popular Failure Analysis estimate for risk of death in various activities related to per-hour of activity. That is the risk is estimated for every hour or any unit of time one engages the activity and is an even more difficut estimate ... useful for comparing say the risk of scuba versus skydiving, or BASE jumping.

http://www.afn.org/~savanna/risk.htm

As you can see from the numbers, it makes for interesting statistical anomalies needing 'interpretation.'

 

[HammerNoMore]

Actually, to be honest with you, I think the skew goes in the other direction. If you look at the group of people most likely to get struck by lighting or attacked by a shark, i.e. golfers vs. beachgoers, I think you'd find that the number of people hitting beaches far outweighs the number on golf courses.


James

 

[ReefGuy]

Another thing worth looking at is the ratio to spearing vs non spearing divers bitten.

 

[oversea]

We could calculate the statistic based upon divers and people who carry large steel poles during storm!! would that help Sorry, thought it was funny

 

[H2Andy]

well, seeing as how sharks (the sine qua non of a shark attack) keep dwindling in numbers, the likelihood of attack should, ipso facto, be declining as well from its already infinitsemely low rate

 

[Mako Mark]

someone should poll the board on who has been bitten by sharks.

I personally have not, thaough I have fed them on numerous occasions over the years (dont flame me for that please), but I do have a mate that was.

He was diving on a coral reef that was supposedly within the national park, and found a fishing net there with a live grey nurse shark stuck in it.

A couple of his buddies and him tried to rescue it and in the process, the shark attached itself to his belly and removed a hamburger sized chunk of skin.

The shark was saved.

 

[H2Andy]

good idea

 

[getwet2]

Here's something else to think about!

As you are lounging on the beach contemplating wether to go in the water or not, do not do this under a coconut palm. I read an article about coconut fatalities vs shark fatalities and the coconuts were in the lead.

 

[DivePartner1]

An actuary is going through the security to board a plane. They find he has a bomb. When they ask why:

Actuary: "To make sure the plane is safe"
Security: "You mean you don't want to blow it up?"
Actuary: "Hardly, that's the LAST thing I'd want."
Security: "So why carry a bomb on board?"
Actuary: "Well, from your experience what are the chances of someone bringing a bomb onto a plane? About a million to one?"
Security: "That's about right."
Actuary: "Then what do you think the odds are of TWO people bringing a bomb onto the same plane? . . . ."

 

[getwet2]

I see the logic!